Senaro Personal Finance

before
{"properties":{"age_65_plus_count":{"default":null,"description":"Number of filers aged 65 or older, each adding the additional standard deduction. Integer from 0 to 2. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["integer","null"]},"annual_gross_income":{"default":null,"description":"Annual gross income, the MAGI proxy for the bracket and the SALT cap. Decimal from 0 to 1,000,000,000. Required when apply_tax_benefit is true; otherwise not used.","type":["number","null"]},"apply_tax_benefit":{"default":null,"description":"Whether to apply the federal tax benefit model (TY2025/TY2026 SALT caps, mortgage interest deduction, PMI deductibility). When true, filing_status, tax_year and annual_gross_income are required. Optional; defaults to false when omitted. The §121 home-sale gain exclusion applies only at sale points 24 months or more after purchase (IRC §121(a) 2-of-5-year test); year 1 of yearly_series, months 1-23 in monthly_series, and any horizon under 24 months use no exclusion. Separately, IRC §1222(3) makes a holding period of 12 months or less short-term, taxed at ordinary rates instead of the long-term rates otherwise applied, on the home-sale gain and the renter's portfolio gain alike (24 months vs. 12 months are two different thresholds); this tool applies that split exactly to the home-sale gain, and to the renter's portfolio at annual grain: prior years' contributions are compounded together as one long-term lot rather than aged individually, so months inside a year understate short-term gain.","type":["boolean","null"]},"basis_capitalizable_pct_override":{"default":null,"description":"Percentage of the buy-side closing cost that is capitalizable into the §121 adjusted basis (IRS Pub 523 split: abstract fees, title search, recording fees, survey fees, transfer taxes, owner's title insurance). Decimal from 0 to 100; 0 means a HomePrice-only basis, 100 means the full closing cost is in basis. Optional; defaults to 50% (Senaro deterministic midpoint) when omitted. Supply your actual HUD-1 split when available.","type":["number","null"]},"blind_count":{"default":null,"description":"Number of blind filers, each adding the additional standard deduction. Integer from 0 to 2. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["integer","null"]},"charitable":{"default":null,"description":"Charitable contributions. Decimal from 0 to 1,000,000,000; TY2026 and later apply a 0.5%-of-AGI floor per OBBBA §70425. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["number","null"]},"chart_title":{"default":null,"description":"Override for the chart title. Must not contain em-dashes or en-dashes. Max 120 characters. Optional.","maxLength":120,"type":["string","null"]},"down_payment_pct":{"default":null,"description":"Down payment as a percentage of the home price. Decimal from 0 to 100; 0 is valid (zero-down programs). Optional; defaults to 20% when omitted.","type":["number","null"]},"filing_status":{"default":null,"description":"Tax filing status: 'Single', 'MFJ', 'MFS' or 'HoH'. Required when apply_tax_benefit is true; otherwise not used.","type":["string","null"]},"hoa_monthly":{"default":null,"description":"Monthly HOA dues on the BUY path. Decimal from 0 to 1,000,000,000. Optional; defaults to 0 when omitted.","type":["number","null"]},"home_appreciation_pct":{"default":null,"description":"Annual home price appreciation as a percentage. Decimal from -50 to 50. Optional; defaults to the cited 4.25% (FHFA HPI) when omitted; override for your market.","type":["number","null"]},"home_insurance_pct":{"default":null,"description":"Annual home insurance as a percentage of home value. Decimal from 0 to 15. Optional; defaults to 0.65% when omitted; override for your market.","type":["number","null"]},"home_price":{"description":"Home purchase price. Decimal, greater than 0 and at most 1,000,000,000. REQUIRED, no default.","type":"number"},"horizon_years":{"default":null,"description":"Projection horizon in years. Integer from 1 to 40. Optional; when omitted, the response returns snapshots at years 5, 10 and 30.","type":["integer","null"]},"inflation_pct":{"default":null,"description":"Inflation as a percentage, for the real_terms toggle. Decimal, at least 0 and less than 100. Optional; when omitted, a nominal run uses 2.5%, and a real_terms run uses the horizon-based default: 2.0% for a horizon of 7 years or less, 2.6% for 8 to 19 years, 2.5% for 20 years or more.","type":["number","null"]},"investment_return_pct":{"default":null,"description":"RENT path annual return as a percentage, an EFFECTIVE ANNUAL rate; the monthly compounding step is (1+pct/100)^(1/12)-1. Decimal from -50 to 30. Optional; defaults to 10.0% when omitted.","type":["number","null"]},"loan_origination_date":{"default":null,"description":"Mortgage origination date, YYYY-MM-DD. Selects the mortgage interest deduction cap: on or before 2017-12-15 the $1M cap, after it the $750k cap (Single and MFJ; MFS caps are half). Only used when apply_tax_benefit is true. Optional; omitting it uses the post-2017 cap.","type":["string","null"]},"loan_term_months":{"default":null,"description":"Mortgage term in months. Integer from 1 to 480. Optional; defaults to 360 (a 30-year fixed) when omitted.","type":["integer","null"]},"maintenance_pct":{"default":null,"description":"Annual maintenance as a percentage of home value. Decimal from 0 to 20. Optional; defaults to the cited 1.5% (Harvard JCHS) when omitted; override for your market.","type":["number","null"]},"monthly_rent":{"description":"Monthly rent on the RENT path. Decimal from 0 to 1,000,000,000; 0 is valid (a free-housing baseline). REQUIRED, no default.","type":"number"},"mortgage_rate_pct":{"description":"Mortgage annual rate as a percentage, e.g. 6.75 for 6.75%. Decimal, greater than 0 and at most 100. Never cached; provide the current rate. REQUIRED, no default.","type":"number"},"other_itemizable":{"default":null,"description":"Other itemizable deductions, such as medical expenses above 7.5% of AGI or casualty losses. Decimal from 0 to 1,000,000,000. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["number","null"]},"output":{"description":"Valid values: 'summary' (default), 'inline'. 'summary' returns headline scalars and per-horizon snapshots with the heavy series stripped. 'inline' returns the full payload including yearly_series[] and monthly_series[] for chart rendering.","enum":["summary","inline",null],"type":["string","null"]},"pmi_annual":{"default":null,"description":"Annual PMI premium in dollars while PMI is active. Decimal from 0 to 1,000,000,000. Only used when apply_tax_benefit is true. Optional; when omitted it is derived from pmi_pct and the original loan amount.","type":["number","null"]},"pmi_pct":{"default":null,"description":"Annual PMI rate as a percentage of the loan. Decimal from 0 to 5. Optional; defaults to 0.5% when omitted. The removal threshold is set by pmi_removal_ltv_pct.","type":["number","null"]},"pmi_removal_ltv_pct":{"default":null,"description":"Loan-balance trigger for PMI removal, as a percentage loan-to-value. Decimal from 50 to 100. Optional; omitted, it is the 78% HPA automatic-termination threshold; provided (e.g. 80), it is whichever of 78% or your value is reached first. The rejection guard applies only when down_payment_pct is below 20 and the resolved pmi_pct is above 0, the range where PMI applies: there, a value at or above the loan's own initial LTV is rejected, because the requested removal point would already be met at the first payment, so no PMI would be modeled for any month of the loan. When the resolved pmi_pct is 0, or down_payment_pct is 20 or more, no such check runs, whatever the LTV. Either way PMI also stops at the statutory amortization midpoint of the original term (12 U.S.C. §4901(7), §4902(c)), which this value cannot postpone.","type":["number","null"]},"property_tax_pct":{"default":null,"description":"Annual property tax as a percentage of home value. Decimal from 0 to 10. Optional; defaults to 0.88% when omitted; override for your market.","type":["number","null"]},"purchase_year_points":{"default":null,"description":"Discount points paid at origination, as a percentage of the loan. Decimal from 0 to 4. Counted as cash paid at closing on every call; when apply_tax_benefit is true they are also deducted in year 1. Optional; defaults to 0 when omitted.","type":["number","null"]},"real_terms":{"default":null,"description":"Whether to deflate the output series to a real-terms view. Optional; defaults to false when omitted.","type":["boolean","null"]},"rent_growth_pct":{"default":null,"description":"Annual rent escalation as a percentage. Decimal from -50 to 50. Optional; defaults to the cited 3.4% (BLS CPI ROPR) when omitted; override for your market.","type":["number","null"]},"sell_side_pct":{"default":null,"description":"Sell-side transaction cost as a percentage of the sale price. Decimal from 0 to 25. Optional; defaults to the cited 7.5% (Redfin post-NAR) when omitted; override for your market.","type":["number","null"]},"state_local_tax":{"default":null,"description":"State and local tax paid (state income or sales tax), for the SALT cap. Decimal from 0 to 1,000,000,000. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["number","null"]},"tax_year":{"default":null,"description":"Tax year: 2025 or 2026. Integer. Required when apply_tax_benefit is true; otherwise not used.","type":["integer","null"]}},"required":["home_price","monthly_rent","mortgage_rate_pct"],"type":"object"}

after
{"properties":{"age_65_plus_count":{"default":null,"description":"Number of filers aged 65 or older, each adding the additional standard deduction. Integer from 0 to 2. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["integer","null"]},"annual_gross_income":{"default":null,"description":"Annual gross income, the MAGI proxy for the bracket and the SALT cap. Decimal from 0 to 1,000,000,000. Required when apply_tax_benefit is true; otherwise not used.","type":["number","null"]},"apply_tax_benefit":{"default":null,"description":"Whether to apply the federal tax benefit model (SALT cap following the statute's year-by-year schedule, mortgage interest deduction, PMI deductibility). When true, filing_status, tax_year and annual_gross_income are required. Optional; defaults to false when omitted. The §121 home-sale gain exclusion applies only at sale points 24 months or more after purchase (IRC §121(a) 2-of-5-year test); year 1 of yearly_series, months 1-23 in monthly_series, and any horizon under 24 months use no exclusion. Separately, IRC §1222(3) makes a holding period of 12 months or less short-term, taxed at ordinary rates instead of the long-term rates otherwise applied, on the home-sale gain and the renter's portfolio gain alike (24 months vs. 12 months are two different thresholds); this tool applies that split exactly to the home-sale gain, and to the renter's portfolio at annual grain: prior years' contributions are compounded together as one long-term lot rather than aged individually, so months inside a year understate short-term gain.","type":["boolean","null"]},"basis_capitalizable_pct_override":{"default":null,"description":"Percentage of the buy-side closing cost that is capitalizable into the §121 adjusted basis (IRS Pub 523 split: abstract fees, title search, recording fees, survey fees, transfer taxes, owner's title insurance). Decimal from 0 to 100; 0 means a HomePrice-only basis, 100 means the full closing cost is in basis. Optional; defaults to 50% (Senaro deterministic midpoint) when omitted. Supply your actual HUD-1 split when available.","type":["number","null"]},"blind_count":{"default":null,"description":"Number of blind filers, each adding the additional standard deduction. Integer from 0 to 2. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["integer","null"]},"charitable":{"default":null,"description":"Charitable contributions. Decimal from 0 to 1,000,000,000; TY2026 and later apply a 0.5%-of-AGI floor per OBBBA §70425. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["number","null"]},"chart_title":{"default":null,"description":"Override for the chart title. Must not contain em-dashes or en-dashes. Max 120 characters. Optional.","maxLength":120,"type":["string","null"]},"down_payment_pct":{"default":null,"description":"Down payment as a percentage of the home price. Decimal from 0 to 100; 0 is valid (zero-down programs). Optional; defaults to 20% when omitted.","type":["number","null"]},"filing_status":{"default":null,"description":"Tax filing status: 'Single', 'MFJ', 'MFS' or 'HoH'. Required when apply_tax_benefit is true; otherwise not used.","type":["string","null"]},"hoa_monthly":{"default":null,"description":"Monthly HOA dues on the BUY path. Decimal from 0 to 1,000,000,000. Optional; defaults to 0 when omitted.","type":["number","null"]},"home_appreciation_pct":{"default":null,"description":"Annual home price appreciation as a percentage. Decimal from -50 to 50. Optional; defaults to the cited 4.25% (FHFA HPI) when omitted; override for your market.","type":["number","null"]},"home_insurance_pct":{"default":null,"description":"Annual home insurance as a percentage of home value. Decimal from 0 to 15. Optional; defaults to 0.65% when omitted; override for your market.","type":["number","null"]},"home_price":{"description":"Home purchase price. Decimal, greater than 0 and at most 1,000,000,000. REQUIRED, no default.","type":"number"},"horizon_years":{"default":null,"description":"Projection horizon in years. Integer from 1 to 40. Optional; when omitted, the response returns snapshots at years 5, 10 and 30.","type":["integer","null"]},"inflation_pct":{"default":null,"description":"Inflation as a percentage, for the real_terms toggle. Decimal, at least 0 and less than 100. Optional; when omitted, a nominal run uses 2.5%, and a real_terms run uses the horizon-based default: 2.0% for a horizon of 7 years or less, 2.6% for 8 to 19 years, 2.5% for 20 years or more.","type":["number","null"]},"investment_return_pct":{"default":null,"description":"RENT path annual return as a percentage, an EFFECTIVE ANNUAL rate; the monthly compounding step is (1+pct/100)^(1/12)-1. Decimal from -50 to 30. Optional; defaults to 10.0% when omitted.","type":["number","null"]},"loan_origination_date":{"default":null,"description":"Mortgage origination date, YYYY-MM-DD. Selects the mortgage interest deduction cap: on or before 2017-12-15 the $1M cap, after it the $750k cap (Single and MFJ; MFS caps are half). Only used when apply_tax_benefit is true. Optional; omitting it uses the post-2017 cap.","type":["string","null"]},"loan_term_months":{"default":null,"description":"Mortgage term in months. Integer from 1 to 480. Optional; defaults to 360 (a 30-year fixed) when omitted.","type":["integer","null"]},"maintenance_pct":{"default":null,"description":"Annual maintenance as a percentage of home value. Decimal from 0 to 20. Optional; defaults to the cited 1.5% (Harvard JCHS) when omitted; override for your market.","type":["number","null"]},"monthly_rent":{"description":"Monthly rent on the RENT path. Decimal from 0 to 1,000,000,000; 0 is valid (a free-housing baseline). REQUIRED, no default.","type":"number"},"mortgage_rate_pct":{"description":"Mortgage annual rate as a percentage, e.g. 6.75 for 6.75%. Decimal, greater than 0 and at most 100. Never cached; provide the current rate. REQUIRED, no default.","type":"number"},"other_itemizable":{"default":null,"description":"Other itemizable deductions, such as medical expenses above 7.5% of AGI or casualty losses. Decimal from 0 to 1,000,000,000. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["number","null"]},"output":{"description":"Valid values: 'summary' (default), 'inline'. 'summary' returns headline scalars and per-horizon snapshots with the heavy series stripped. 'inline' returns the full payload including yearly_series[] and monthly_series[] for chart rendering.","enum":["summary","inline",null],"type":["string","null"]},"pmi_annual":{"default":null,"description":"Annual PMI premium in dollars while PMI is active. Decimal from 0 to 1,000,000,000. Only used when apply_tax_benefit is true. Optional; when omitted it is derived from pmi_pct and the original loan amount.","type":["number","null"]},"pmi_pct":{"default":null,"description":"Annual PMI rate as a percentage of the loan. Decimal from 0 to 5. Optional; defaults to 0.5% when omitted. The removal threshold is set by pmi_removal_ltv_pct.","type":["number","null"]},"pmi_removal_ltv_pct":{"default":null,"description":"Loan-balance trigger for PMI removal, as a percentage loan-to-value. Decimal from 50 to 100. Optional; omitted, it is the 78% HPA automatic-termination threshold; provided (e.g. 80), it is whichever of 78% or your value is reached first. The rejection guard applies only when down_payment_pct is below 20 and the resolved pmi_pct is above 0, the range where PMI applies: there, a value at or above the loan's own initial LTV is rejected, because the requested removal point would already be met at the first payment, so no PMI would be modeled for any month of the loan. When the resolved pmi_pct is 0, or down_payment_pct is 20 or more, no such check runs, whatever the LTV. Either way PMI also stops at the statutory amortization midpoint of the original term (12 U.S.C. §4901(7), §4902(c)), which this value cannot postpone.","type":["number","null"]},"property_tax_pct":{"default":null,"description":"Annual property tax as a percentage of home value. Decimal from 0 to 10. Optional; defaults to 0.88% when omitted; override for your market.","type":["number","null"]},"purchase_year_points":{"default":null,"description":"Discount points paid at origination, as a percentage of the loan. Decimal from 0 to 4. Counted as cash paid at closing on every call; when apply_tax_benefit is true they are also deducted in year 1. Optional; defaults to 0 when omitted.","type":["number","null"]},"real_terms":{"default":null,"description":"Whether to deflate the output series to a real-terms view. Optional; defaults to false when omitted.","type":["boolean","null"]},"rent_growth_pct":{"default":null,"description":"Annual rent escalation as a percentage. Decimal from -50 to 50. Optional; defaults to the cited 3.4% (BLS CPI ROPR) when omitted; override for your market.","type":["number","null"]},"sell_side_pct":{"default":null,"description":"Sell-side transaction cost as a percentage of the sale price. Decimal from 0 to 25. Optional; defaults to the cited 7.5% (Redfin post-NAR) when omitted; override for your market.","type":["number","null"]},"state_local_tax":{"default":null,"description":"State and local tax paid (state income or sales tax), for the SALT cap. Decimal from 0 to 1,000,000,000. Only used when apply_tax_benefit is true. Optional; defaults to 0 when omitted.","type":["number","null"]},"tax_year":{"default":null,"description":"Tax year for year 1 of the horizon: 2025 or 2026. Integer. Required when apply_tax_benefit is true; otherwise not used. Horizon year y uses tax year (tax_year + y - 1) on both the tax benefit and the sale-side capital-gains tax; the SALT cap follows the statute's own schedule for that year, and every other indexed amount holds at its last-loaded table value beyond it.","type":["integer","null"]}},"required":["home_price","monthly_rent","mortgage_rate_pct"],"type":"object"}

before
{"properties":{"apply_rate_cap":{"default":null,"description":"Whether to cap each card's APR at the regulatory ceiling before simulating. Optional; defaults to false when omitted.","type":["boolean","null"]},"cards":{"description":"Credit cards to pay off, 1 to 20. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"cards is required and must be an array.\"); the two are not the same rejection. Every card may carry segments[]. Max 100 segments total across all cards in the request. Per-card, per-type caps: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan.","items":{"properties":{"annual_fee":{"description":"Annual fee in dollars, $0 to $1,000,000,000. Optional; defaults to 0. Charged at month 1 and every twelfth month after, while the card carries a balance.","type":["number","null"]},"cash_advance_apr_pct":{"description":"Cash advance APR as a percentage, greater than 0 and up to 100. Required when cash_advance_balance is greater than 0: cash advances have no promotional 0% product, so a 0% rate on a real advance balance is a data-entry error.","type":["number","null"]},"cash_advance_balance":{"description":"Cash advance balance in dollars, $0 to $1,000,000,000. Optional; defaults to 0 when omitted. A POSITIVE value alongside a non-empty segments[] is rejected, the same way purchase_balance is. An explicit 0 is accepted.","type":["number","null"]},"minimum_payment":{"description":"Minimum payment in dollars, $0 to $1,000,000,000 (optional, omit or set 0 to auto-calculate). Where it binds, the card is locked at max(minimum_payment, that card's issuer minimum computed at month 1), and that locked amount is paid every month. On calculate_cc_payoff it binds ONLY when fixed_payments = true; on the DEFAULT path (fixed_payments = false) it is NOT used, because the plan recomputes each card's issuer minimum from its current balance every month, and the response discloses that as MINIMUM_PAYMENT_NOT_BINDING. On compare_strategies there is no fixed_payments parameter and supplying one is rejected: the avalanche and snowball arms ALWAYS run locked, so the value DOES bind and moves both arms, while the minimum-payments-only baseline always recomputes and ignores it, disclosed as MINIMUM_PAYMENT_NOT_BINDING_IN_BASELINE.","type":["number","null"]},"monthly_spend":{"description":"Recurring monthly purchase amount charged to this card's purchase balance before interest accrues, $0 to $50,000 per month. Optional; defaults to 0. Use the segment-level monthly_spend instead when supplying segments[].","type":["number","null"]},"name":{"description":"Card label, e.g. 'Chase Sapphire', 120 characters or fewer. Optional; a card without a name is auto-numbered ('Card 1', 'Card 2', and so on). Echoed into per-card results and warning text. A name over the cap is replaced in error field paths by a key built from its zero-based card index, written as '#0 (name over cap)', '#1 (name over cap)' and so on.","type":["string","null"]},"plan_fees_monthly":{"description":"Recurring monthly card fee in dollars, $0 to $1,000,000,000, e.g. a pay-over-time plan fee. Optional; defaults to 0. Charged every month while the card carries a balance.","type":["number","null"]},"purchase_apr_pct":{"description":"Purchase APR as a percentage, 0 to 100, e.g. 24.99 not 0.2499. Required when purchase_balance is greater than 0: an omitted APR would silently compute $0 interest.","type":["number","null"]},"purchase_balance":{"description":"Purchase balance in dollars, $0 to $1,000,000,000. Required unless segments[] carries at least one segment: an omitted purchase_balance would silently report a $0, 0-month payoff. Supplying a POSITIVE value alongside a non-empty segments[] is rejected, since the two would be competing sources for the same balance. An explicit 0 is accepted.","type":["number","null"]},"segments":{"description":"Per-segment breakdown of this card's balances. Optional; when it carries at least one segment it SUPERSEDES purchase_balance and cash_advance_balance, and a POSITIVE value in either of those is rejected. An empty segments[] is treated as absent, so purchase_balance is then required. At most 100 segments across the whole request. Per card, per type: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan. Each item carries its own type, balance, rate and payment priority; see the type field on the item for the per-type field matrix.","items":{"properties":{"apr_pct":{"default":null,"description":"Annual percentage rate for this segment, 0 to 100, e.g. 24.99 not 0.2499. Required when balance is greater than 0 on purchase, cash_advance, balance_transfer and promotional. On cash_advance it must be greater than 0 whenever a balance is carried. Must be 0 on installment_plan, which uses monthly_fee instead, so omitting it there is the correct shape.","type":["number","null"]},"balance":{"description":"Segment balance in dollars, $0 to $1,000,000,000. REQUIRED on every segment type: an omitted balance would silently report a $0, 0-month payoff, so it is rejected instead. An explicit 0 is valid, for example a paid-off balance_transfer segment kept for schedule continuity.","type":"number"},"extra_payment_order":{"default":null,"description":"Extra-payment tie-break priority, 0 or more, where 0 means this segment never receives extra payment. Optional on every type, and the default for installment_plan. Only breaks a tie between segments sharing the exact same current APR, since the Credit CARD Act (TILA §164(b), 15 U.S.C. §1666c(b)) / 12 CFR 1026.53(a) always pays the highest-current-APR segment first regardless of this value.","type":["integer","null"]},"merchant_name":{"default":null,"description":"Label for an installment plan's merchant, 120 characters or fewer. Optional on installment_plan, ignored on every other type.","type":["string","null"]},"min_payment_order":{"default":null,"description":"Minimum-payment tie-break priority, 1 or more. Optional on every type. The minimum first pays any installment_plan's locked plan_payment_due in full, then the lowest-current-APR segment; this value only breaks a tie between segments sharing both the same current APR and the same installment-plan status.","type":["integer","null"]},"monthly_fee":{"default":null,"description":"Fixed fee charged each month while an installment plan's term is active, $0 or more and no greater than plan_payment_due. Optional on installment_plan. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"monthly_spend":{"default":null,"description":"Recurring monthly purchase amount posted to this segment before interest accrues, $0 to $50,000 per month. Optional on purchase. A negative value is rejected as NEGATIVE_BALANCE on every type. On every type other than purchase a positive value is rejected with FIELD_NOT_ALLOWED_HERE, since those balances do not accept new purchases; an explicit 0 is accepted.","type":["number","null"]},"plan_payment_due":{"default":null,"description":"Locked monthly payment for an installment plan, principal plus monthly_fee. Required on installment_plan, greater than $0, at least monthly_fee, and no more than $1,000,000,000. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"promo_expires_month":{"default":null,"description":"Month at which apr_pct flips to revert_apr_pct, 1 to 480. Required on balance_transfer and promotional. Ignored on purchase, cash_advance and installment_plan.","type":["integer","null"]},"remaining_payments":{"default":null,"description":"Payments left in an installment plan's stated term, 0 or more. Optional on installment_plan, ignored on every other type. 0 means the term has ALREADY ended and is valid with any balance, including a positive residual. From 1 up, the balance must be clearable within the stated term and must not be clearable a month early.","type":["integer","null"]},"revert_apr_pct":{"default":null,"description":"Rate this segment reverts to once its promo expires, 0 to 100, and at least apr_pct. Required on balance_transfer and promotional. Ignored on purchase and cash_advance. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate rather than repricing.","type":["number","null"]},"stop_spend_month":{"default":null,"description":"Month index at which recurring spend stops, 0 or more. Read on purchase only, and range checked on every type. Omit to spend for the whole projection.","type":["integer","null"]},"type":{"description":"Segment type. REQUIRED on every segment: omitting it is rejected. Per-type field matrix. Every field below is classified for every segment type: REQUIRED (omitting it is rejected), OPTIONAL (accepted either way and read), IGNORED (accepted and never read for this type, though a value can still fail the field's own range check), or REJECTED (supplying a disallowed value is an error; the field's own rule below says exactly which values are disallowed). Value rules are stated separately from applicability, because a field can be accepted on a type and still be restricted there. The validators are the authority; this matrix describes them.\n- type: REQUIRED on every type. Values: one of purchase, cash_advance, balance_transfer, promotional, installment_plan.\n- balance: REQUIRED on every type. Values: $0 to $1,000,000,000; above $50,000 returns a HIGH_CARD_BALANCE warning, not an error.\n- apr_pct: REQUIRED on purchase, cash_advance, balance_transfer, promotional; OPTIONAL on installment_plan. Values: 0 to 100 as a percentage, e.g. 24.99 not 0.2499. The REQUIRED classification above applies when balance is greater than 0; a zero-balance segment may omit it. Must be greater than 0 on cash_advance carrying a balance. Must equal 0 on installment_plan, where omitting it is the correct shape.\n- revert_apr_pct: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance; REJECTED on installment_plan. Values: 0 to 100, and at least apr_pct. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate.\n- promo_expires_month: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance, installment_plan. Values: 1 to 480.\n- monthly_fee: OPTIONAL on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: $0 or more, and no greater than plan_payment_due, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- plan_payment_due: REQUIRED on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: greater than $0, at least monthly_fee, and no more than $1,000,000,000, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- remaining_payments: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 0 or more. 0 means the stated term has ALREADY ended and is valid with any balance. From 1 up, balance must be clearable within the stated term.\n- min_payment_order: OPTIONAL on every type. Values: 1 or more; breaks a tie only between segments sharing both the same current APR and the same installment-plan status.\n- extra_payment_order: OPTIONAL on every type. Values: 0 or more; 0 means skip. Breaks a tie only between segments sharing the exact same current APR.\n- merchant_name: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 120 characters or fewer.\n- monthly_spend: OPTIONAL on purchase; REJECTED on cash_advance, balance_transfer, promotional, installment_plan. Values: $0 to $50,000 per month. A negative value is rejected as NEGATIVE_BALANCE on every type, purchase included. On every type other than purchase a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; an explicit 0 is accepted.\n- stop_spend_month: OPTIONAL on purchase; IGNORED on cash_advance, balance_transfer, promotional, installment_plan. Values: 0 or more; range checked on every type, read only on purchase.","type":"string"}},"required":["type","balance"],"type":"object"},"type":["array","null"]},"stop_spend_month":{"description":"Month index at which this card's recurring spend stops, 0 or more. Optional; omit to spend for the whole projection.","type":["integer","null"]}},"type":"object"},"type":"array"},"chart_title":{"default":null,"description":"Override for the chart title. Optional; must not contain an em dash or en dash. Max 120 characters.","type":["string","null"]},"extra_monthly_payment":{"default":null,"description":"Extra monthly payment in dollars, $0 to $1,000,000,000, applied on top of the required minimums. Optional; defaults to 0 when omitted.","type":["number","null"]},"fixed_payments":{"default":null,"description":"Whether to hold each card's payment constant for the whole payoff. Optional; defaults to false when omitted. When true, each card's payment is locked at max(cards[].minimum_payment, that card's issuer minimum computed at month 1), and the total monthly budget (those locked amounts plus extra_monthly_payment) is held constant for the whole payoff, so once a card is paid off its freed-up payment rolls forward onto the remaining cards. This is the ONLY mode in which cards[].minimum_payment affects calculate_cc_payoff's result; compare_strategies has no fixed_payments parameter and binds minimum_payment on both of its strategy arms regardless.","type":["boolean","null"]},"full_schedule":{"default":null,"description":"Whether to return the full per-card month-by-month schedule. Optional; defaults to false when omitted. The per-card monthly_schedule is capped at 1000 rows total across cards and months, so later months are omitted on a long multi-card payoff; the portfolio-level monthly_totals series is always complete and is the one to read for the whole timeline.","type":["boolean","null"]},"include_card_timeline":{"default":null,"description":"Whether to add the card_timeline block, a per-card view of when each card clears. Optional; defaults to false when omitted.","type":["boolean","null"]},"output":{"description":"Valid values: 'summary' (default), 'inline'. summary returns a compact response with a data_preview block; inline returns the full payload.","enum":["summary","inline"],"type":"string"},"per_segment":{"default":null,"description":"Whether each schedule row carries its per-segment breakdown. Optional; defaults to true when omitted.","type":["boolean","null"]},"strategy":{"default":null,"description":"Payoff order: 'avalanche' pays the highest APR first, 'snowball' the smallest balance first. Optional; defaults to 'avalanche' when omitted. Matched case-insensitively, and the response echoes the canonical lowercase form actually simulated.","type":["string","null"]},"windfalls":{"default":null,"description":"One-time principal payments, at most 12, e.g. a tax refund or a year-end bonus. Optional; a JSON null is treated as omitted. When non-empty the response gains baseline, with_windfalls, months_saved_vs_baseline, interest_saved_vs_baseline, windfalls_applied[] and windfalls_unused[]; an empty array returns the same shape as omitting it.","items":{"properties":{"amount":{"description":"Dollar amount of the windfall, greater than 0. Required per entry.","type":["number","null"]},"label":{"description":"Optional label for this windfall, e.g. 'Tax refund' or 'Year-end bonus'. Max 120 characters.","type":["string","null"]},"month":{"description":"Month index the windfall is applied, 0 or more. 0 means applied before month 1's interest; N >= 1 applies at the end of calendar month N. Required per entry.","type":["integer","null"]}},"type":["object","null"]},"type":["array","null"]}},"required":["cards"],"type":"object"}

after
{"properties":{"apply_rate_cap":{"default":null,"description":"Whether to cap each card's APR at the regulatory ceiling before simulating. Optional; defaults to false when omitted.","type":["boolean","null"]},"cards":{"description":"Credit cards to pay off, 1 to 20. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"cards is required and must be an array.\"); the two are not the same rejection. Every card may carry segments[]. Max 100 segments total across all cards in the request. Per-card, per-type caps: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan.","items":{"properties":{"annual_fee":{"description":"Annual fee in dollars, $0 to $1,000,000,000. Optional; defaults to 0. Charged at month 1 and every twelfth month after, while the card carries a balance.","type":["number","null"]},"cash_advance_apr_pct":{"description":"Cash advance APR as a percentage, greater than 0 and up to 100. Required when cash_advance_balance is greater than 0: cash advances have no promotional 0% product, so a 0% rate on a real advance balance is a data-entry error.","type":["number","null"]},"cash_advance_balance":{"description":"Cash advance balance in dollars, $0 to $1,000,000,000. Optional; defaults to 0 when omitted. A POSITIVE value alongside a non-empty segments[] is rejected, the same way purchase_balance is. An explicit 0 is accepted.","type":["number","null"]},"minimum_payment":{"description":"Minimum payment in dollars, $0 to $1,000,000,000 (optional, omit or set 0 to auto-calculate). Where it binds, the card is locked at max(minimum_payment, that card's issuer minimum computed at month 1), and that locked amount is paid every month. On calculate_cc_payoff it binds ONLY when fixed_payments = true; on the DEFAULT path (fixed_payments = false) it is NOT used, because the plan recomputes each card's issuer minimum from its current balance every month, and the response discloses that as MINIMUM_PAYMENT_NOT_BINDING. On compare_payoff_strategies there is no fixed_payments parameter and supplying one is rejected: the avalanche and snowball arms ALWAYS run locked, so the value DOES bind and moves both arms, while the minimum-payments-only baseline always recomputes and ignores it, disclosed as MINIMUM_PAYMENT_NOT_BINDING_IN_BASELINE.","type":["number","null"]},"monthly_spend":{"description":"Recurring monthly purchase amount charged to this card's purchase balance before interest accrues, $0 to $50,000 per month. Optional; defaults to 0. Use the segment-level monthly_spend instead when supplying segments[].","type":["number","null"]},"name":{"description":"Card label, e.g. 'Chase Sapphire', 120 characters or fewer. Optional; a card without a name is auto-numbered ('Card 1', 'Card 2', and so on). Echoed into per-card results and warning text. A name over the cap is replaced in error field paths by a key built from its zero-based card index, written as '#0 (name over cap)', '#1 (name over cap)' and so on.","maxLength":120,"type":["string","null"]},"plan_fees_monthly":{"description":"Recurring monthly card fee in dollars, $0 to $1,000,000,000, e.g. a pay-over-time plan fee. Optional; defaults to 0. Charged every month while the card carries a balance.","type":["number","null"]},"purchase_apr_pct":{"description":"Purchase APR as a percentage, 0 to 100, e.g. 24.99 not 0.2499. Required when purchase_balance is greater than 0: an omitted APR would silently compute $0 interest.","maximum":100,"minimum":0,"type":["number","null"]},"purchase_balance":{"description":"Purchase balance in dollars, $0 to $1,000,000,000. Required unless segments[] carries at least one segment: an omitted purchase_balance would silently report a $0, 0-month payoff. Supplying a POSITIVE value alongside a non-empty segments[] is rejected, since the two would be competing sources for the same balance. An explicit 0 is accepted.","type":["number","null"]},"segments":{"description":"Per-segment breakdown of this card's balances. Optional; when it carries at least one segment it SUPERSEDES purchase_balance and cash_advance_balance, and a POSITIVE value in either of those is rejected. An empty segments[] is treated as absent, so purchase_balance is then required. At most 100 segments across the whole request. Per card, per type: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan. Each item carries its own type, balance, rate and payment priority; see the type field on the item for the per-type field matrix.","items":{"properties":{"apr_pct":{"default":null,"description":"Annual percentage rate for this segment, 0 to 100, e.g. 24.99 not 0.2499. Required when balance is greater than 0 on purchase, cash_advance, balance_transfer and promotional. On cash_advance it must be greater than 0 whenever a balance is carried. Must be 0 on installment_plan, which uses monthly_fee instead, so omitting it there is the correct shape.","type":["number","null"]},"balance":{"description":"Segment balance in dollars, $0 to $1,000,000,000. REQUIRED on every segment type: an omitted balance would silently report a $0, 0-month payoff, so it is rejected instead. An explicit 0 is valid, for example a paid-off balance_transfer segment kept for schedule continuity.","type":"number"},"extra_payment_order":{"default":null,"description":"Extra-payment tie-break priority, 0 or more, where 0 means this segment never receives extra payment. Optional on every type, and the default for installment_plan. Only breaks a tie between segments sharing the exact same current APR, since the Credit CARD Act (TILA §164(b), 15 U.S.C. §1666c(b)) / 12 CFR 1026.53(a) always pays the highest-current-APR segment first regardless of this value.","type":["integer","null"]},"merchant_name":{"default":null,"description":"Label for an installment plan's merchant, 120 characters or fewer. Optional on installment_plan, ignored on every other type.","type":["string","null"]},"min_payment_order":{"default":null,"description":"Minimum-payment tie-break priority, 1 or more. Optional on every type. The minimum first pays any installment_plan's locked plan_payment_due in full, then the lowest-current-APR segment; this value only breaks a tie between segments sharing both the same current APR and the same installment-plan status.","type":["integer","null"]},"monthly_fee":{"default":null,"description":"Fixed fee charged each month while an installment plan's term is active, $0 or more and no greater than plan_payment_due. Optional on installment_plan. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"monthly_spend":{"default":null,"description":"Recurring monthly purchase amount posted to this segment before interest accrues, $0 to $50,000 per month. Optional on purchase. A negative value is rejected as NEGATIVE_BALANCE on every type. On every type other than purchase a positive value is rejected with FIELD_NOT_ALLOWED_HERE, since those balances do not accept new purchases; an explicit 0 is accepted.","type":["number","null"]},"plan_payment_due":{"default":null,"description":"Locked monthly payment for an installment plan, principal plus monthly_fee. Required on installment_plan, greater than $0, at least monthly_fee, and no more than $1,000,000,000. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"promo_expires_month":{"default":null,"description":"Month at which apr_pct flips to revert_apr_pct, 1 to 480. Required on balance_transfer and promotional. Ignored on purchase, cash_advance and installment_plan.","type":["integer","null"]},"remaining_payments":{"default":null,"description":"Payments left in an installment plan's stated term, 0 or more. Optional on installment_plan, ignored on every other type. 0 means the term has ALREADY ended and is valid with any balance, including a positive residual. From 1 up, the balance must be clearable within the stated term and must not be clearable a month early.","type":["integer","null"]},"revert_apr_pct":{"default":null,"description":"Rate this segment reverts to once its promo expires, 0 to 100, and at least apr_pct. Required on balance_transfer and promotional. Ignored on purchase and cash_advance. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate rather than repricing.","type":["number","null"]},"stop_spend_month":{"default":null,"description":"Month index at which recurring spend stops, 0 or more. Read on purchase only, and range checked on every type. Omit to spend for the whole projection.","type":["integer","null"]},"type":{"description":"Segment type. REQUIRED on every segment: omitting it is rejected. Per-type field matrix. Every field below is classified for every segment type: REQUIRED (omitting it is rejected), OPTIONAL (accepted either way and read), IGNORED (accepted and never read for this type, though a value can still fail the field's own range check), or REJECTED (supplying a disallowed value is an error; the field's own rule below says exactly which values are disallowed). Value rules are stated separately from applicability, because a field can be accepted on a type and still be restricted there. The validators are the authority; this matrix describes them.\n- type: REQUIRED on every type. Values: one of purchase, cash_advance, balance_transfer, promotional, installment_plan.\n- balance: REQUIRED on every type. Values: $0 to $1,000,000,000; above $50,000 returns a HIGH_CARD_BALANCE warning, not an error.\n- apr_pct: REQUIRED on purchase, cash_advance, balance_transfer, promotional; OPTIONAL on installment_plan. Values: 0 to 100 as a percentage, e.g. 24.99 not 0.2499. The REQUIRED classification above applies when balance is greater than 0; a zero-balance segment may omit it. Must be greater than 0 on cash_advance carrying a balance. Must equal 0 on installment_plan, where omitting it is the correct shape.\n- revert_apr_pct: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance; REJECTED on installment_plan. Values: 0 to 100, and at least apr_pct. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate.\n- promo_expires_month: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance, installment_plan. Values: 1 to 480.\n- monthly_fee: OPTIONAL on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: $0 or more, and no greater than plan_payment_due, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- plan_payment_due: REQUIRED on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: greater than $0, at least monthly_fee, and no more than $1,000,000,000, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- remaining_payments: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 0 or more. 0 means the stated term has ALREADY ended and is valid with any balance. From 1 up, balance must be clearable within the stated term.\n- min_payment_order: OPTIONAL on every type. Values: 1 or more; breaks a tie only between segments sharing both the same current APR and the same installment-plan status.\n- extra_payment_order: OPTIONAL on every type. Values: 0 or more; 0 means skip. Breaks a tie only between segments sharing the exact same current APR.\n- merchant_name: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 120 characters or fewer.\n- monthly_spend: OPTIONAL on purchase; REJECTED on cash_advance, balance_transfer, promotional, installment_plan. Values: $0 to $50,000 per month. A negative value is rejected as NEGATIVE_BALANCE on every type, purchase included. On every type other than purchase a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; an explicit 0 is accepted.\n- stop_spend_month: OPTIONAL on purchase; IGNORED on cash_advance, balance_transfer, promotional, installment_plan. Values: 0 or more; range checked on every type, read only on purchase.","type":"string"}},"required":["type","balance"],"type":"object"},"type":["array","null"]},"stop_spend_month":{"description":"Month index at which this card's recurring spend stops, 0 or more. Optional; omit to spend for the whole projection.","type":["integer","null"]}},"type":"object"},"maxItems":20,"type":"array"},"chart_title":{"default":null,"description":"Override for the chart title. Optional; must not contain an em dash or en dash. Max 120 characters.","maxLength":120,"type":["string","null"]},"extra_monthly_payment":{"default":null,"description":"Extra monthly payment in dollars, $0 to $1,000,000,000, applied on top of the required minimums. Optional; defaults to 0 when omitted.","type":["number","null"]},"fixed_payments":{"default":null,"description":"Whether to hold each card's payment constant for the whole payoff. Optional; defaults to false when omitted. When true, each card's payment is locked at max(cards[].minimum_payment, that card's issuer minimum computed at month 1), and the total monthly budget (those locked amounts plus extra_monthly_payment) is held constant for the whole payoff, so once a card is paid off its freed-up payment rolls forward onto the remaining cards. This is the ONLY mode in which cards[].minimum_payment affects calculate_cc_payoff's result; compare_payoff_strategies has no fixed_payments parameter and binds minimum_payment on both of its strategy arms regardless.","type":["boolean","null"]},"full_schedule":{"default":null,"description":"Whether to return the full per-card month-by-month schedule. Optional; defaults to false when omitted. The per-card monthly_schedule is capped at 1000 rows total across cards and months, so later months are omitted on a long multi-card payoff; the portfolio-level monthly_totals series is always complete and is the one to read for the whole timeline.","type":["boolean","null"]},"include_card_timeline":{"default":null,"description":"Whether to add the card_timeline block, a per-card view of when each card clears. Optional; defaults to false when omitted.","type":["boolean","null"]},"output":{"description":"Valid values: 'summary' (default), 'inline'. summary returns a compact response with a data_preview block; inline returns the full payload.","enum":["summary","inline",null],"type":["string","null"]},"per_segment":{"default":null,"description":"Whether each schedule row carries its per-segment breakdown. Optional; defaults to true when omitted.","type":["boolean","null"]},"strategy":{"default":null,"description":"Payoff order: 'avalanche' pays the highest APR first, 'snowball' the smallest balance first. Optional; defaults to 'avalanche' when omitted. Matched case-insensitively, and the response echoes the canonical lowercase form actually simulated.","enum":["avalanche","snowball",null],"type":["string","null"]},"windfalls":{"default":null,"description":"One-time principal payments, at most 12, e.g. a tax refund or a year-end bonus. Optional; a JSON null is treated as omitted. When non-empty the response gains baseline, with_windfalls, months_saved_vs_baseline, interest_saved_vs_baseline, windfalls_applied[] and windfalls_unused[]; an empty array returns the same shape as omitting it.","items":{"properties":{"amount":{"description":"Dollar amount of the windfall, greater than 0. Required per entry.","type":["number","null"]},"label":{"description":"Optional label for this windfall, e.g. 'Tax refund' or 'Year-end bonus'. Max 120 characters.","maxLength":120,"type":["string","null"]},"month":{"description":"Month index the windfall is applied, 0 or more. 0 means applied before month 1's interest; N >= 1 applies at the end of calendar month N. Required per entry.","type":["integer","null"]}},"type":["object","null"]},"maxItems":12,"type":["array","null"]}},"required":["cards"],"type":"object"}

before
{"properties":{"additional_income":{"default":null,"description":"Additional monthly income: side income, rental income, or bonuses. Optional; defaults to 0 when omitted. Must be zero or more.","type":["number","null"]},"annual_income":{"default":null,"description":"Annual gross income in dollars, divided by 12 to get monthly income. Exactly one of gross_monthly_income or annual_income is required. Must be at least $0.01, one cent, the smallest amount of money.","type":["number","null"]},"existing_debts":{"default":null,"description":"Existing debts to include in the DTI calculation. Optional; omit it or send an empty array for no existing debts. A JSON null is rejected; omit the field instead. At most 50 debts are allowed.","items":{"properties":{"apr_pct":{"description":"Annual percentage rate, as a percentage (0-100), e.g. 18.5 for 18.5%. Optional.","type":["number","null"]},"balance":{"description":"Current balance in dollars. Optional; used for payoff cost analysis in what-if scenarios.","type":["number","null"]},"monthly_payment":{"description":"Monthly payment in dollars. Required per debt; must be positive.","type":["number","null"]},"months_remaining":{"description":"Months remaining on this debt. Optional; used for the 10-month rule exclusion.","type":["integer","null"]},"name":{"description":"Optional label for this debt, e.g. 'Car Loan'.","type":["string","null"]},"type":{"description":"Debt type: 'auto', 'student', 'credit_card', 'personal', 'mortgage', 'heloc', 'child_support', or 'other'. Optional, defaults to 'other' when omitted; an unrecognized value warns rather than rejects.","type":["string","null"]}},"type":["object","null"]},"type":["array","null"]},"family_size":{"default":null,"description":"Household size for the VA residual income guideline. Supply family_size and property_state together, or neither. Optional; must be between 1 and 20.","type":["integer","null"]},"gross_monthly_income":{"default":null,"description":"Gross monthly income in dollars. Exactly one of gross_monthly_income or annual_income is required. Must be at least $0.01, one cent, the smallest amount of money.","type":["number","null"]},"hoa_monthly":{"default":null,"description":"Monthly homeowners association dues in dollars. Optional; defaults to 0 when omitted. Must be zero or more.","type":["number","null"]},"home_insurance_annual":{"default":null,"description":"Annual home insurance in dollars. Optional; if omitted, estimated at 0.65% of the proposed home price. Must be zero or more.","type":["number","null"]},"include_what_if":{"default":null,"description":"Whether to generate what-if scenarios showing how paying off a debt, increasing income, or reducing the home price would improve DTI. Optional; defaults to true when omitted.","type":["boolean","null"]},"monthly_maintenance_and_utilities":{"default":null,"description":"Estimated monthly maintenance and utilities for the proposed property. 38 CFR 36.4340 calls for a realistic estimate of this figure for the property and local utility rates and sets no numeric multiplier itself, but VA underwriting guidance (the Lender's Handbook, Pamphlet 26-7) publishes a per-square-foot multiplier for this same estimate. Applying it needs the property's square footage, which this tool does not currently collect, so Senaro has no default to offer here and you supply the aggregate monthly amount instead. Supplying BOTH this field and monthly_taxes_and_retirement_withholding, together with proposed_home_price and a computable family_size/property_state, computes qualification.va.residual_income_comparison: your ACTUAL monthly residual income, its ratio to the va_residual_income_guideline figure, and whether residual_income_meets_review_waiver_margin (residual income at or above 120% of the guideline) is met. The shelter expense used here excludes any PMI (VA loans carry no monthly PMI; 38 CFR 36.4313(e) sets a funding fee instead, commonly financed into the loan; see va_funding_fee_financed_monthly for the financed-fee field). 38 CFR 36.4340(c)(3)'s review-waiver condition is CONJUNCTIVE: it also requires the back-end debt-to-income ratio (qualification.va.your_back_end) to exceed 41%, which this field does not by itself confirm. Check both fields together. Even when both hold, (c)(3) only WAIVES a second-level review requirement; it is not itself an approval. Whether this file is actually approved is an underwriting determination Senaro does not make and no input combination here determines. Missing any one of the needed inputs reads qualification.va.residual_income_comparison.status 'not_computable' with every reason named. Optional; must be zero or more.","type":["number","null"]},"monthly_taxes_and_retirement_withholding":{"default":null,"description":"Your federal, state, and FICA tax withholding, plus any amount paid or withheld for retirement, monthly. 38 CFR 36.4340(f)(13) treats these as one class of deduction from gross income. Optional; must be zero or more.","type":["number","null"]},"pmi_monthly":{"default":null,"description":"Monthly PMI (private mortgage insurance) in dollars. Optional; if omitted, auto-estimated at 0.5% of the loan annually when loan-to-value exceeds 80%. Feeds the conventional-basis PITI, so it moves with_proposed.front_end_dti, with_proposed.back_end_dti, with_proposed.front_end_breakdown, the conventional qualification row, and what_if.scenarios[].new_front_end_dti and new_back_end_dti. VA carries no PMI, and FHA and USDA always compute their own upfront-plus-annual mortgage insurance instead, at every loan-to-value, never this override. Must be zero or more.","type":["number","null"]},"property_state":{"default":null,"description":"Two-letter USPS state code, or 'DC'/'PR'/'GU'/'VI'/'AS'/'MP'. Supply family_size and property_state together, or neither. Together these compute the VA residual income guideline (38 CFR 36.4340(e)) in va_residual_income_guideline: the dollar amount VA's tables require for this family size, region, and loan amount (derived from proposed_home_price; not computable without it), plus the 38 CFR 36.4340(c)(3) review-waiver figure. Computed only for family_size 1-7 and a property_state among the 50 states, DC, or PR (not GU, VI, AS, or MP; 38 CFR 36.4340(e) assigns no region to those four); outside those bounds, or without proposed_home_price, va_residual_income_guideline.status reads 'not_computable' with the reason instead. This block alone is a LOOKUP, not a verdict: it never compares against your actual residual income by itself. Optional.","type":["string","null"]},"property_tax_annual":{"default":null,"description":"Annual property tax in dollars. Optional; if omitted, estimated at 0.88% of the proposed home price. Must be zero or more.","type":["number","null"]},"proposed_debt":{"default":null,"description":"A proposed new debt, as an alternative to proposed_home_price. Provide at most one of proposed_debt or proposed_home_price; providing neither computes the current DTI only. Optional; a JSON null is treated as omitted, the same as leaving the field out.","properties":{"includes_tax_insurance":{"description":"Whether monthly_payment already includes tax and insurance. Optional, defaults to true when omitted; if false and type is 'mortgage', warns that lenders use full PITI for DTI.","type":["boolean","null"]},"monthly_payment":{"description":"Monthly payment in dollars. Required; must be positive.","type":["number","null"]},"name":{"description":"Optional label for this proposed debt.","type":["string","null"]},"type":{"description":"Debt type: 'auto', 'student', 'credit_card', 'personal', 'mortgage', 'heloc', 'child_support', or 'other'. Optional, defaults to 'mortgage' when omitted; an unrecognized value is rejected.","type":["string","null"]}},"type":["object","null"]},"proposed_down_payment_pct":{"default":null,"description":"Down payment as a percent of the proposed home price, e.g. 20 for 20%. Optional; defaults to 20 when omitted. Must be between 0 and 99.9 (100% cash purchases are not supported).","type":["number","null"]},"proposed_home_price":{"default":null,"description":"Proposed home purchase price in dollars. Provide at most one of proposed_debt or proposed_home_price; providing neither computes the current DTI only. Auto-calculates full PITI (principal, interest, taxes, insurance). Optional; must be at least $0.01, one cent, the smallest amount of money.","type":["number","null"]},"proposed_rate_pct":{"default":null,"description":"Proposed mortgage interest rate as a percent, e.g. 7.0 for 7.0%. Optional; the 7.0% default applies whenever this field is omitted, whether the proposal is proposed_debt or proposed_home_price. The default-rate warning fires only when proposed_home_price is used. Must be between 0 and 20.","type":["number","null"]},"proposed_term_years":{"default":null,"description":"Proposed mortgage term in years. Optional; defaults to 30 when omitted. Must be between 1 and 40.","type":["integer","null"]},"transaction_purpose":{"default":null,"description":"Mortgage transaction purpose: 'purchase', 'refinance', or 'streamlined_assist'. Optional, defaults to 'purchase' when omitted. Affects USDA only, and only what is disclosed. USDA's 32% PITI and 44% Total Debt figures are purchase-transaction waiver conditions (HB-1-3555 11.3.A.2), disclosed rather than applied as ceilings: Senaro cannot observe how the file is underwritten, so a USDA ratio overage is never 'ineligible' on any transaction purpose. For a refinance, 11.3.B states debt ratios 'are not limited to the maximum purchase debt ratio thresholds', so where the note fires it names both figures and states that neither applies. Streamlined-assist refinances require no debt ratio calculation at all. Conventional, FHA and VA are unaffected.","type":["string","null"]},"va_funding_fee_financed_monthly":{"default":null,"description":"The additional monthly payment from financing a VA funding fee into the loan balance, if any. 38 CFR 36.4313(e)'s applicable percentage depends on down payment, prior VA-loan use, and service category, none of which Senaro collects, so there is no default. If omitted while any VA figure that depends on it is produced, meaning qualification.va.your_back_end and its verdict, any what_if VA ratio, what_if.max_affordable_home.va, or qualification.va.residual_income_comparison, a VA_FUNDING_FEE_NOT_MODELED warning discloses that no fee is assumed. The home-price-reduction what_if scenario's hypothetical price is fixed before the fee is considered, so a supplied fee is scaled to that EXACT hypothetical loan size, since 38 CFR 36.4313(e)'s fee is a percentage of loan principal. what_if.max_affordable_home.va is a two-pass approximation instead, so its supplied fee is scaled to an ESTIMATE of the hypothetical loan size, not the exact figure reported; the PMI, tax, and insurance reservation itself is an EXACT closed-form solve, so only this fee-scaling step is approximate. Without proposed_home_price there is no reference loan size to scale from either way, so the raw fee is reserved unscaled instead, and a VA_FUNDING_FEE_NOT_SCALED warning discloses it. This is mutually exclusive with VA_FUNDING_FEE_NOT_MODELED by construction, since one requires the fee omitted and the other requires it supplied. Optional; must be zero or more.","type":["number","null"]}},"type":"object"}

after
{"properties":{"additional_income":{"default":null,"description":"Additional monthly income: side income, rental income, or bonuses. Optional; defaults to 0 when omitted. Must be zero or more.","type":["number","null"]},"annual_income":{"default":null,"description":"Annual gross income in dollars, divided by 12 to get monthly income. Exactly one of gross_monthly_income or annual_income is required. Must be at least $0.01, one cent, the smallest amount of money.","minimum":0.01,"type":["number","null"]},"existing_debts":{"default":null,"description":"Existing debts to include in the DTI calculation. Optional; omit it or send an empty array for no existing debts. A JSON null is rejected; omit the field instead. At most 50 debts are allowed.","items":{"properties":{"apr_pct":{"description":"Annual percentage rate, as a percentage (0-100), e.g. 18.5 for 18.5%. Optional.","type":["number","null"]},"balance":{"description":"Current balance in dollars. Optional; used for payoff cost analysis in what-if scenarios.","type":["number","null"]},"monthly_payment":{"description":"Monthly payment in dollars. Required per debt; must be positive.","type":["number","null"]},"months_remaining":{"description":"Months remaining on this debt. Optional; used for the 10-month rule exclusion.","type":["integer","null"]},"name":{"description":"Optional label for this debt, e.g. 'Car Loan'. At most 120 characters.","maxLength":120,"type":["string","null"]},"type":{"description":"Debt type: 'auto', 'student', 'credit_card', 'personal', 'mortgage', 'heloc', 'child_support', or 'other'. Optional, defaults to 'other' when omitted. An unrecognized value of at most 120 characters warns rather than rejects; a longer one is rejected.","maxLength":120,"type":["string","null"]}},"type":["object","null"]},"maxItems":50,"type":["array","null"]},"family_size":{"default":null,"description":"Household size for the VA residual income guideline. Supply family_size and property_state together, or neither. Optional; must be between 1 and 20.","maximum":20,"type":["integer","null"]},"gross_monthly_income":{"default":null,"description":"Gross monthly income in dollars. Exactly one of gross_monthly_income or annual_income is required. Must be at least $0.01, one cent, the smallest amount of money.","minimum":0.01,"type":["number","null"]},"hoa_monthly":{"default":null,"description":"Monthly homeowners association dues in dollars. Optional; defaults to 0 when omitted. Must be zero or more.","type":["number","null"]},"home_insurance_annual":{"default":null,"description":"Annual home insurance in dollars. Optional; if omitted, estimated at 0.65% of the proposed home price. Must be zero or more.","type":["number","null"]},"include_what_if":{"default":null,"description":"Whether to generate what-if scenarios showing how paying off a debt, increasing income, or reducing the home price would improve DTI. Optional; defaults to true when omitted.","type":["boolean","null"]},"monthly_maintenance_and_utilities":{"default":null,"description":"Estimated monthly maintenance and utilities for the proposed property. 38 CFR 36.4340 calls for a realistic estimate of this figure for the property and local utility rates and sets no numeric multiplier itself, but VA underwriting guidance (the Lender's Handbook, Pamphlet 26-7) publishes a per-square-foot multiplier for this same estimate. Applying it needs the property's square footage, which this tool does not currently collect, so Senaro has no default to offer here and you supply the aggregate monthly amount instead. Supplying BOTH this field and monthly_taxes_and_retirement_withholding, together with proposed_home_price and a computable family_size/property_state, computes qualification.va.residual_income_comparison: your ACTUAL monthly residual income, its ratio to the va_residual_income_guideline figure, and whether residual_income_meets_review_waiver_margin (residual income at or above 120% of the guideline) is met. The shelter expense used here excludes any PMI (VA loans carry no monthly PMI; 38 CFR 36.4313(e) sets a funding fee instead, commonly financed into the loan; see va_funding_fee_financed_monthly for the financed-fee field). 38 CFR 36.4340(c)(3)'s review-waiver condition is CONJUNCTIVE: it also requires the back-end debt-to-income ratio (qualification.va.your_back_end) to exceed 41%, which this field does not by itself confirm. Check both fields together. Even when both hold, (c)(3) only WAIVES a second-level review requirement; it is not itself an approval. Whether this file is actually approved is an underwriting determination Senaro does not make and no input combination here determines. Missing any one of the needed inputs reads qualification.va.residual_income_comparison.status 'not_computable' with every reason named. Optional; must be zero or more.","type":["number","null"]},"monthly_taxes_and_retirement_withholding":{"default":null,"description":"Your federal, state, and FICA tax withholding, plus any amount paid or withheld for retirement, monthly. 38 CFR 36.4340(f)(13) treats these as one class of deduction from gross income. Optional; must be zero or more.","type":["number","null"]},"pmi_monthly":{"default":null,"description":"Monthly PMI (private mortgage insurance) in dollars. Optional; if omitted, auto-estimated at 0.5% of the loan annually when loan-to-value exceeds 80%. Feeds the conventional-basis PITI, so it moves with_proposed.front_end_dti, with_proposed.back_end_dti, with_proposed.front_end_breakdown, the conventional qualification row, and what_if.scenarios[].new_front_end_dti and new_back_end_dti. VA carries no PMI, and FHA and USDA always compute their own upfront-plus-annual mortgage insurance instead, at every loan-to-value, never this override. Must be zero or more.","type":["number","null"]},"property_state":{"default":null,"description":"Two-letter USPS state code, or 'DC'/'PR'/'GU'/'VI'/'AS'/'MP'. Supply family_size and property_state together, or neither. Together these compute the VA residual income guideline (38 CFR 36.4340(e)) in va_residual_income_guideline: the dollar amount VA's tables require for this family size, region, and loan amount (derived from proposed_home_price; not computable without it), plus the 38 CFR 36.4340(c)(3) review-waiver figure. Computed only for family_size 1-7 and a property_state among the 50 states, DC, or PR (not GU, VI, AS, or MP; 38 CFR 36.4340(e) assigns no region to those four); outside those bounds, or without proposed_home_price, va_residual_income_guideline.status reads 'not_computable' with the reason instead. This block alone is a LOOKUP, not a verdict: it never compares against your actual residual income by itself. Optional.","type":["string","null"]},"property_tax_annual":{"default":null,"description":"Annual property tax in dollars. Optional; if omitted, estimated at 0.88% of the proposed home price. Must be zero or more.","type":["number","null"]},"proposed_debt":{"default":null,"description":"A proposed new debt, as an alternative to proposed_home_price. Provide at most one of proposed_debt or proposed_home_price; providing neither computes the current DTI only. Optional; a JSON null is treated as omitted, the same as leaving the field out.","properties":{"includes_tax_insurance":{"description":"Whether monthly_payment already includes tax and insurance. Optional, defaults to true when omitted; if false and type is 'mortgage', warns that lenders use full PITI for DTI.","type":["boolean","null"]},"monthly_payment":{"description":"Monthly payment in dollars. Required; must be positive.","type":["number","null"]},"name":{"description":"Optional label for this proposed debt. At most 120 characters.","maxLength":120,"type":["string","null"]},"type":{"description":"Debt type: 'auto', 'student', 'credit_card', 'personal', 'mortgage', 'heloc', 'child_support', or 'other'. Optional, defaults to 'mortgage' when omitted; an unrecognized value is rejected.","enum":["credit_card","auto","student","personal","mortgage","heloc","child_support","other",null],"type":["string","null"]}},"type":["object","null"]},"proposed_down_payment_pct":{"default":null,"description":"Down payment as a percent of the proposed home price, e.g. 20 for 20%. Optional; defaults to 20 when omitted. Must be between 0 and 99.9 (100% cash purchases are not supported).","type":["number","null"]},"proposed_home_price":{"default":null,"description":"Proposed home purchase price in dollars. Provide at most one of proposed_debt or proposed_home_price; providing neither computes the current DTI only. Auto-calculates full PITI (principal, interest, taxes, insurance). Optional; must be at least $0.01, one cent, the smallest amount of money.","minimum":0.01,"type":["number","null"]},"proposed_rate_pct":{"default":null,"description":"Proposed mortgage interest rate as a percent, e.g. 7.0 for 7.0%. Optional; the 7.0% default applies whenever this field is omitted, whether the proposal is proposed_debt or proposed_home_price. The default-rate warning fires only when proposed_home_price is used. Must be between 0 and 20.","type":["number","null"]},"proposed_term_years":{"default":null,"description":"Proposed mortgage term in years. Optional; defaults to 30 when omitted. Must be between 1 and 40.","type":["integer","null"]},"transaction_purpose":{"default":null,"description":"Mortgage transaction purpose: 'purchase', 'refinance', or 'streamlined_assist'. Optional, defaults to 'purchase' when omitted. Affects USDA only, and only what is disclosed. USDA's 32% PITI and 44% Total Debt figures are purchase-transaction waiver conditions (HB-1-3555 11.3.A.2), disclosed rather than applied as ceilings: Senaro cannot observe how the file is underwritten, so a USDA ratio overage is never 'ineligible' on any transaction purpose. For a refinance, 11.3.B states debt ratios 'are not limited to the maximum purchase debt ratio thresholds', so where the note fires it names both figures and states that neither applies. Streamlined-assist refinances require no debt ratio calculation at all. Conventional, FHA and VA are unaffected.","enum":["purchase","refinance","streamlined_assist",null],"type":["string","null"]},"va_funding_fee_financed_monthly":{"default":null,"description":"The additional monthly payment from financing a VA funding fee into the loan balance, if any. 38 CFR 36.4313(e)'s applicable percentage depends on down payment, prior VA-loan use, and service category, none of which Senaro collects, so there is no default. If omitted while any VA figure that depends on it is produced, meaning qualification.va.your_back_end and its verdict, any what_if VA ratio, what_if.max_affordable_home.va, or qualification.va.residual_income_comparison, a VA_FUNDING_FEE_NOT_MODELED warning discloses that no fee is assumed. The home-price-reduction what_if scenario's hypothetical price is fixed before the fee is considered, so a supplied fee is scaled to that EXACT hypothetical loan size, since 38 CFR 36.4313(e)'s fee is a percentage of loan principal. what_if.max_affordable_home.va is a two-pass approximation instead, so its supplied fee is scaled to an ESTIMATE of the hypothetical loan size, not the exact figure reported; the PMI, tax, and insurance reservation itself is an EXACT closed-form solve, so only this fee-scaling step is approximate. Without proposed_home_price there is no reference loan size to scale from either way, so the raw fee is reserved unscaled instead, and a VA_FUNDING_FEE_NOT_SCALED warning discloses it. This is mutually exclusive with VA_FUNDING_FEE_NOT_MODELED by construction, since one requires the fee omitted and the other requires it supplied. Optional; must be zero or more.","type":["number","null"]}},"type":"object"}

before
{"properties":{"bt_apr_pct":{"default":null,"description":"Balance-transfer APR as a percentage, 0-100, e.g. 0 for a 0% promo. Required when include_balance_transfer is true and bt_offers is omitted. bt_offers, when supplied, overrides this and the other three bt_* scalars below. The 0-100 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["number","null"]},"bt_fee_pct":{"default":null,"description":"Balance-transfer fee as a percentage of the transferred balance, 0-10. Optional; defaults to 3.0 when omitted. bt_offers, when supplied, overrides this. The 0-10 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["number","null"]},"bt_manual_transfers":{"default":null,"description":"Exact per-card transfer amounts. Required when bt_transfer_strategy is 'manual'; each entry's card_name must match a name in cards[]. Optional otherwise; a JSON null is treated as omitted, the same as leaving the field out.","items":{"properties":{"amount":{"description":"Dollar amount to transfer from this card, greater than $0, up to $1,000,000,000. Required per entry.","type":["number","null"]},"card_name":{"description":"Card name; must match a name in cards[]. Required per entry. Max 120 characters.","type":["string","null"]}},"type":["object","null"]},"type":["array","null"]},"bt_offers":{"default":null,"description":"Balance-transfer offers to compare head-to-head, 1 to 10, preferred over the four scalar bt_* fields above when comparing two or more offers: when supplied, bt_offers overrides bt_apr_pct, bt_promo_months, bt_regular_apr_pct, and bt_fee_pct, and their range checks are skipped. The response includes a balance_transfer_offers block with per-offer simulation results, selected_offer_index, selected_offer_label, selected_offer_reason, and all_offers_trap. Optional; a JSON null is rejected, unlike bt_manual_transfers and windfalls below, where a JSON null is treated as omitted.","items":{"properties":{"apr_pct":{"description":"Offer APR as a percentage, 0-100, e.g. 0 for a 0% promo. Required per offer.","type":["number","null"]},"fee_pct":{"description":"Balance-transfer fee for this offer, as a percentage of the transferred balance, 0-10. Optional; defaults to 3.0 when omitted.","type":["number","null"]},"label":{"description":"Label for this offer. Optional; defaults to '<apr_pct>% / <promo_months>mo' when omitted. Max 120 characters.","type":["string","null"]},"promo_months":{"description":"This offer's promo period in months, 1-60. Optional; defaults to 18 when omitted.","type":["integer","null"]},"regular_apr_pct":{"description":"APR that applies after this offer's promo period ends, as a percentage, 0-100. Optional; defaults to 25.20 when omitted.","type":["number","null"]}},"type":["object","null"]},"type":["array","null"]},"bt_promo_months":{"default":null,"description":"Balance-transfer promo period in months, 1-60. Optional; defaults to 18 when omitted. bt_offers, when supplied, overrides this. The 1-60 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["integer","null"]},"bt_regular_apr_pct":{"default":null,"description":"APR that applies after the promo period ends, as a percentage, 0-100. Optional; defaults to 25.20 when omitted. bt_offers, when supplied, overrides this. The 0-100 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["number","null"]},"bt_transfer_limit":{"default":null,"description":"Cap on the total dollar amount transferred to the balance-transfer card, at least $0.01. When set, only this amount moves to the BT card; remaining balances stay on original cards, and a combined simulation runs both halves together, correctly redistributing freed minimum payments. Optional; when omitted, the entire balance is transferred (legacy behavior). Needs include_balance_transfer or bt_offers.","type":["number","null"]},"bt_transfer_strategy":{"default":null,"description":"How to choose which balances move when bt_transfer_limit is less than your total debt: 'highest_apr_first' (transfer from highest-APR segments first, maximizes interest savings), 'highest_balance_first' (transfer largest balances first), or 'manual' (use bt_manual_transfers to specify exact amounts per card). Optional; defaults to 'highest_apr_first' when omitted. Needs bt_transfer_limit.","type":["string","null"]},"cards":{"description":"Credit cards to include, 1 to 20. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"cards must be a JSON array.\"); the two are not the same rejection. segments and stop_spend_month are not supported by this tool and are rejected; a non-zero monthly_spend, annual_fee, or plan_fees_monthly is rejected too, but zero (including an explicit 0) is accepted and dropped for all three: this tool always reads the flat purchase_balance / cash_advance_balance fields on each card below, never segments[] balances, and card-level fees and ongoing spend are not modeled here. Those five fields are supported by calculate_cc_payoff and compare_strategies instead.","items":{"properties":{"cash_advance_apr_pct":{"description":"Cash advance APR as a percentage, greater than 0, up to 100. Required when cash_advance_balance is greater than 0.","type":["number","null"]},"cash_advance_balance":{"description":"Cash advance balance in dollars, $0 to $1,000,000,000. Optional; defaults to 0 when omitted.","type":["number","null"]},"minimum_payment":{"description":"Minimum payment in dollars, $0 to $1,000,000,000. Optional; 0 or omitted auto-calculates the bank minimum. Used as the locked floor for the constant keep-cards payment: each card pays max(your minimum, the bank minimum), held constant and rolled forward as cards clear.","type":["number","null"]},"name":{"description":"Card label, e.g. 'Chase Sapphire'. Optional; a card without a name is auto-numbered ('Card 1', 'Card 2', ...). Max 120 characters.","type":["string","null"]},"purchase_apr_pct":{"description":"Purchase APR as a percentage, 0-100, e.g. 22.99. Required per card.","type":["number","null"]},"purchase_balance":{"description":"Purchase balance in dollars, $0 to $1,000,000,000. Required per card.","type":["number","null"]}},"type":"object"},"type":"array"},"chart_title":{"default":null,"description":"Override for the chart title. Optional; must not contain an em dash or en dash. Max 120 characters.","type":["string","null"]},"consolidation_loan":{"description":"Loan terms for the consolidation option. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"consolidation_loan must be an object.\"); the two are not the same rejection.","properties":{"annual_rate_pct":{"description":"Annual interest rate for the consolidation loan, as a percentage, 0-36, e.g. 10.99. Required.","type":["number","null"]},"include_fee_in_principal":{"description":"Whether the origination fee is rolled into the loan principal rather than paid upfront. Optional; defaults to true when omitted. A JSON null is rejected; omit the field instead of sending null.","type":["boolean","null"]},"origination_fee_flat":{"description":"Flat-dollar origination fee, $0 to $10,000. Optional; defaults to 0 when omitted, and takes precedence over origination_fee_pct when it produces a larger fee. A JSON null is rejected; omit the field instead of sending null.","type":["number","null"]},"origination_fee_pct":{"description":"Origination fee as a percentage of loan principal, 0-10. Optional; defaults to 0 when omitted. A JSON null is rejected, unlike every other optional field on this tool; omit the field instead of sending null.","type":["number","null"]},"term_months":{"description":"Consolidation loan term in months, 12-84. Required.","type":["integer","null"]}},"type":"object"},"current_strategy":{"default":null,"description":"Your current payoff strategy, compared against the consolidation loan / balance-transfer alternative: 'avalanche' or 'snowball'. Optional; defaults to 'avalanche' when omitted. Case-sensitive.","type":["string","null"]},"extra_monthly_payment":{"default":null,"description":"Extra monthly payment in dollars, $0 to $1,000,000,000, applied on top of the required minimums for keep-cards and any balance transfer, and on top of the loan's own required payment for consolidation. Optional; defaults to 0 when omitted. fixed_payments is not a parameter of this tool, unlike calculate_cc_payoff: the keep-cards baseline is always simulated under the canonical constant rolled-forward payment (see comparison_basis in the response); supplying fixed_payments returns an unknown_parameter error.","type":["number","null"]},"full_schedule":{"default":null,"description":"Whether to return the full month-by-month amortization schedule instead of the compact default. Optional; defaults to false when omitted.","type":["boolean","null"]},"include_balance_transfer":{"default":null,"description":"Whether to run a single-offer balance-transfer scenario using the four scalar bt_* fields below. Optional; defaults to false when omitted. Ignored once bt_offers is supplied; use bt_offers when comparing two or more offers.","type":["boolean","null"]},"output":{"description":"Valid values: 'summary' (default), 'inline'. summary: compact response with a data_preview block; no heavy array exists on this response today, so summary and inline are currently identical in content. inline: full payload (currently identical to summary; will diverge once a heavy array is added for chart rendering).","enum":["summary","inline"],"type":"string"},"windfalls":{"default":null,"description":"One-time principal payments, at most 12, same shape as calculate_cc_payoff. Optional; a JSON null is treated as omitted, the same as leaving the field out. When non-empty, the response adds windfalls_applied[] and windfalls_unused[] on keep_cards, on each balance_transfer scenario (and on each offer in balance_transfer_offers.offers[]), on consolidation_loan (single-row per windfall since the loan is a single-balance instrument), and on optimized_consolidation.keep_subset. All scenarios use with-windfalls totals so cross-option ranking stays apples-to-apples, except what_if.same_budget_accelerated, a windfall-free hypothetical about extra-payment behavior, not your actual lump-sum schedule.","items":{"properties":{"amount":{"description":"Dollar amount of the windfall, greater than 0. Required per entry.","type":["number","null"]},"label":{"description":"Optional label for this windfall, e.g. 'Tax refund' or 'Year-end bonus'. Max 120 characters.","type":["string","null"]},"month":{"description":"Month index the windfall is applied, 0 or more. 0 means applied before month 1's interest; N >= 1 applies at the end of calendar month N. Required per entry.","type":["integer","null"]}},"type":["object","null"]},"type":["array","null"]}},"required":["cards","consolidation_loan"],"type":"object"}

before
{"properties":{"toolArguments":{"description":"JSON object with these parameters:\n\ncards (REQUIRED array, max 20):\n  - name: string (optional, auto-generated if omitted)\n  - purchase_balance: decimal >= 0 (REQUIRED unless segments[] is supplied)\n  - purchase_apr_pct: decimal 0-100 as percentage, e.g. 24.99 not 0.2499 (REQUIRED unless segments[] is supplied)\n  - cash_advance_balance: decimal >= 0 (optional, default 0)\n  - cash_advance_apr_pct: decimal > 0, <= 100 (required only if cash_advance_balance > 0)\n  - minimum_payment: decimal >= 0 (optional, omit or set 0 to auto-calculate). Binds ONLY when fixed_payments = true: the card is then locked at max(minimum_payment, that card's issuer minimum computed at month 1), and that locked amount is paid every month. On the DEFAULT path (fixed_payments = false), this value is NOT used: the plan recomputes each card's issuer minimum from its current balance every month, so the monthly budget is the sum of those recomputed minimums plus extra_monthly_payment. To hold a stated payment instead, set fixed_payments = true.\n  - annual_fee: decimal >= 0 (optional, default 0). Charged at month 1 and every 12th month thereafter while the card has a balance.\n  - plan_fees_monthly: decimal >= 0 (optional, default 0). Charged every month while the card has a balance (e.g. pay-over-time plan fee).\n  - segments: array (OPTIONAL; when present, supersedes purchase_balance / cash_advance_balance). Max 100 segments total across all cards in the request. Per-card, per-type caps: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan. Each item:\n      - type: 'purchase' | 'cash_advance' | 'balance_transfer' | 'promotional' | 'installment_plan' (REQUIRED). Use 'promotional' for a balance whose 0% (or below-market) intro APR reverts to a standard rate later and is NOT a balance transfer, e.g. a 0% intro purchase APR; it validates and reverts identically to balance_transfer.\n      - balance: decimal >= 0 (REQUIRED)\n      - apr_pct: decimal 0-100 (REQUIRED for purchase / cash_advance / balance_transfer / promotional; must be 0 for installment_plan; for cash_advance, must be > 0 when balance > 0, since cash advances have no promotional 0% product)\n      - revert_apr_pct: decimal 0-100 (REQUIRED for balance_transfer / promotional; APR after promo expires; not applicable to purchase / cash_advance (silently ignored); REJECTED on installment_plan (FIELD_NOT_ALLOWED_HERE) since installment_plan has no post-term-rate concept: an expired plan's residual keeps its existing rate)\n      - promo_expires_month: int >= 1 (REQUIRED for balance_transfer / promotional; month at which apr_pct flips to revert_apr_pct)\n      - monthly_fee: decimal >= 0 (REQUIRED for installment_plan; fixed fee charged each month while the plan's term is active; stops accruing once the term elapses)\n      - plan_payment_due: decimal > 0 (REQUIRED for installment_plan; locked monthly payment, principal + monthly_fee; keeps being charged every month even after the term elapses, until the balance clears)\n      - remaining_payments: int >= 0 (optional, installment_plan only). 0 means the plan's stated term has ALREADY ended: this is the correct, valid way to model an already-expired plan carrying a residual balance, and it is accepted regardless of balance (an expired plan's residual is a real state, not a data-entry error). When remaining_payments >= 1, it must be consistent with balance / plan_payment_due / monthly_fee: net = plan_payment_due - monthly_fee must be positive, or the plan could never amortize (rejected as INSTALLMENT_PLAN_NET_NOT_POSITIVE); balance must be <= remaining_payments * net (the plan must be able to clear within its stated term) and balance must be > (remaining_payments - 1) * net (the term must not be overstated), either violation rejected as INSTALLMENT_PLAN_TERM_MISMATCH. If a plan has already ended, enter remaining_payments as 0 rather than a positive count that cannot clear the balance. An expired plan (remaining_payments reaches 0 with a positive balance still owed, whether supplied that way or reached by simulation) does not freeze and is never repriced: it keeps receiving its locked plan_payment_due every month at its existing rate until the balance clears. One aggregated PLAN_TERM_ELAPSED_WITH_BALANCE warning fires per card (never one per segment), naming every affected plan on that card and its residual, plus the card total.\n      - merchant_name: string (optional, installment_plan only)\n      - min_payment_order: int >= 1 (optional; the minimum first pays any installment_plan segment's locked plan_payment_due in full, structurally, regardless of APR or this value; among the remaining (revolving) segments it then pays down the lowest-current-APR segment first, issuer practice, not statutorily regulated; this value only breaks a tie between segments that share both the exact same current APR AND the same installment-plan status, in which case the higher-balance segment wins; two segments on the same card sharing a value emit a DUPLICATE_PAYMENT_ORDER warning; a supplied value with no APR-tie partner to ever decide emits PAYMENT_ORDER_NOT_DECISIVE)\n      - extra_payment_order: int >= 0 (optional; 0 = SKIP -- this segment never receives extra payment, the default for installment_plan; a positive value only breaks a tie between segments that share the exact same current APR, since the Credit CARD Act (TILA §164(b), 15 U.S.C. §1666c(b)) / 12 CFR §1026.53(a) always pays the highest-current-APR segment first regardless of this value; two segments on the same card sharing a positive value emit a DUPLICATE_PAYMENT_ORDER warning, duplicate 0s never warn; a supplied value with no APR-tie partner to ever decide emits PAYMENT_ORDER_NOT_DECISIVE -- this hits installment_plan hardest, since it is pinned at 0% APR (apr_pct is not read for this segment type), so a positive override on it can win the tie-break only against another segment also at exactly 0%; whenever any positive-APR segment shares the card, the plan stays ELIGIBLE and sorts LAST behind every positive-APR segment, receiving extra only once those higher-APR balances clear)\n    Response gains per-card interest_saving_balance (sum of APR-bearing segments) and installment_balance_locked (sum of installment_plan segments) when segments[] is supplied.\n\nextra_monthly_payment: decimal >= 0 (optional, default 0)\nstrategy: 'avalanche' | 'snowball' (optional, default 'avalanche')\nfixed_payments: bool (optional, default false). When true, each card's payment is locked at max(cards[].minimum_payment, that card's issuer minimum computed at month 1), and the total monthly budget (sum of those locked amounts plus extra_monthly_payment) is held constant for the whole payoff, so once a card is paid off its freed-up payment rolls forward onto the remaining cards. This is the ONLY mode in which cards[].minimum_payment affects the result; see the minimum_payment field above for what happens on the default path.\napply_rate_cap: bool (optional, default false)\nfull_schedule: bool (optional, default false). The per-card monthly_schedule is capped at 1000 rows total (cards x months); on a long multi-card payoff later months are omitted from monthly_schedule. The portfolio-level monthly_totals series is always complete, so read monthly_totals for the full timeline.\nper_segment: bool (optional, default true)\ninclude_card_timeline: bool (optional, default false)\n\nwindfalls: array of one-time principal payments (optional, default empty, max 12 items). Each item:\n  - month: int >= 0 (REQUIRED). 0 means applied before month 1's interest (same as reducing starting principal). N >= 1 applies at the END of calendar month N, so month N+1's interest is calculated on the post-windfall balance.\n  - amount: decimal > 0 (REQUIRED).\n  - label: string (optional). e.g. 'Tax refund', 'Year-end bonus'.\nWhen any windfalls are present the response gains: baseline, with_windfalls, months_saved_vs_baseline, interest_saved_vs_baseline, windfalls_applied[], windfalls_unused[]. Empty windfalls yields the same response shape as before.\n\nMin-payments-only baseline (v1.7, gap #593): when extra_monthly_payment > 0, windfalls are present, or fixed_payments = true, the response also gains:\n  - min_payments_only: { months, interest_cost, amount_paid, payoff_date } - what happens paying minimums only\n  - interest_saved_vs_min_payments: decimal - total interest saved vs paying minimums only (always >= 0)\n  - months_saved_vs_min_payments: int - months saved vs paying minimums only (when minimums never pay off, capped at MaxMonths minus with-plan months)\nTrivial minimums-only calls (no extra, no windfalls, not fixed) keep their current response shape unchanged.\n\nMinimums-only baseline series (v1.9, B2; bucketed v2.5, #1108): under the same plan-exists condition as min_payments_only above, the response also gains minimums_only_baseline: { months, granularity, buckets[], payoff_date } - the minimums-only balance trajectory bucketed through the same shared aggregator as analysis.buckets[] (same bucket row shape: bucket_index, label, plus the 17 money fields), with granularity auto-selected from THIS series' own term, the same standard rule analysis.granularity itself uses. minimums_only_baseline.granularity is NOT guaranteed to equal analysis.granularity: each series auto-selects independently from its own term, so read each series' own granularity rather than assuming they match. Equal bucket-array length is NOT a valid signal that the two granularities match either: a 24-month primary run (monthly, 24 buckets) and a 24-year minimums-only baseline (yearly, 24 buckets) land on the SAME buckets[].length with DIFFERENT granularities. granularity is the only valid mismatch signal; length is not. Computed from the SAME gated simulation as min_payments_only, so months/payoff_date agree between the two blocks. Absent under the identical trivial-call condition as min_payments_only.\n\nchart_title: string (optional) override for the chart title. Must not contain em-dashes or en-dashes. Max 120 characters.\noutput: 'summary' | 'inline' | 'capture' (optional, default 'summary')\n  'capture' is available on the local stdio transport only; the hosted HTTP transport rejects it with a structured error naming 'summary' and 'inline' as the valid alternatives."}},"required":["toolArguments"],"type":"object"}

after
{"properties":{"apply_rate_cap":{"default":null,"description":"Whether to cap each card's APR at the regulatory ceiling before simulating. Optional; defaults to false when omitted.","type":["boolean","null"]},"cards":{"description":"Credit cards to pay off, 1 to 20. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"cards is required and must be an array.\"); the two are not the same rejection. Every card may carry segments[]. Max 100 segments total across all cards in the request. Per-card, per-type caps: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan.","items":{"properties":{"annual_fee":{"description":"Annual fee in dollars, $0 to $1,000,000,000. Optional; defaults to 0. Charged at month 1 and every twelfth month after, while the card carries a balance.","type":["number","null"]},"cash_advance_apr_pct":{"description":"Cash advance APR as a percentage, greater than 0 and up to 100. Required when cash_advance_balance is greater than 0: cash advances have no promotional 0% product, so a 0% rate on a real advance balance is a data-entry error.","type":["number","null"]},"cash_advance_balance":{"description":"Cash advance balance in dollars, $0 to $1,000,000,000. Optional; defaults to 0 when omitted. A POSITIVE value alongside a non-empty segments[] is rejected, the same way purchase_balance is. An explicit 0 is accepted.","type":["number","null"]},"minimum_payment":{"description":"Minimum payment in dollars, $0 to $1,000,000,000 (optional, omit or set 0 to auto-calculate). Where it binds, the card is locked at max(minimum_payment, that card's issuer minimum computed at month 1), and that locked amount is paid every month. On calculate_cc_payoff it binds ONLY when fixed_payments = true; on the DEFAULT path (fixed_payments = false) it is NOT used, because the plan recomputes each card's issuer minimum from its current balance every month, and the response discloses that as MINIMUM_PAYMENT_NOT_BINDING. On compare_strategies there is no fixed_payments parameter and supplying one is rejected: the avalanche and snowball arms ALWAYS run locked, so the value DOES bind and moves both arms, while the minimum-payments-only baseline always recomputes and ignores it, disclosed as MINIMUM_PAYMENT_NOT_BINDING_IN_BASELINE.","type":["number","null"]},"monthly_spend":{"description":"Recurring monthly purchase amount charged to this card's purchase balance before interest accrues, $0 to $50,000 per month. Optional; defaults to 0. Use the segment-level monthly_spend instead when supplying segments[].","type":["number","null"]},"name":{"description":"Card label, e.g. 'Chase Sapphire', 120 characters or fewer. Optional; a card without a name is auto-numbered ('Card 1', 'Card 2', and so on). Echoed into per-card results and warning text. A name over the cap is replaced in error field paths by a key built from its zero-based card index, written as '#0 (name over cap)', '#1 (name over cap)' and so on.","type":["string","null"]},"plan_fees_monthly":{"description":"Recurring monthly card fee in dollars, $0 to $1,000,000,000, e.g. a pay-over-time plan fee. Optional; defaults to 0. Charged every month while the card carries a balance.","type":["number","null"]},"purchase_apr_pct":{"description":"Purchase APR as a percentage, 0 to 100, e.g. 24.99 not 0.2499. Required when purchase_balance is greater than 0: an omitted APR would silently compute $0 interest.","type":["number","null"]},"purchase_balance":{"description":"Purchase balance in dollars, $0 to $1,000,000,000. Required unless segments[] carries at least one segment: an omitted purchase_balance would silently report a $0, 0-month payoff. Supplying a POSITIVE value alongside a non-empty segments[] is rejected, since the two would be competing sources for the same balance. An explicit 0 is accepted.","type":["number","null"]},"segments":{"description":"Per-segment breakdown of this card's balances. Optional; when it carries at least one segment it SUPERSEDES purchase_balance and cash_advance_balance, and a POSITIVE value in either of those is rejected. An empty segments[] is treated as absent, so purchase_balance is then required. At most 100 segments across the whole request. Per card, per type: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan. Each item carries its own type, balance, rate and payment priority; see the type field on the item for the per-type field matrix.","items":{"properties":{"apr_pct":{"default":null,"description":"Annual percentage rate for this segment, 0 to 100, e.g. 24.99 not 0.2499. Required when balance is greater than 0 on purchase, cash_advance, balance_transfer and promotional. On cash_advance it must be greater than 0 whenever a balance is carried. Must be 0 on installment_plan, which uses monthly_fee instead, so omitting it there is the correct shape.","type":["number","null"]},"balance":{"description":"Segment balance in dollars, $0 to $1,000,000,000. REQUIRED on every segment type: an omitted balance would silently report a $0, 0-month payoff, so it is rejected instead. An explicit 0 is valid, for example a paid-off balance_transfer segment kept for schedule continuity.","type":"number"},"extra_payment_order":{"default":null,"description":"Extra-payment tie-break priority, 0 or more, where 0 means this segment never receives extra payment. Optional on every type, and the default for installment_plan. Only breaks a tie between segments sharing the exact same current APR, since the Credit CARD Act (TILA §164(b), 15 U.S.C. §1666c(b)) / 12 CFR 1026.53(a) always pays the highest-current-APR segment first regardless of this value.","type":["integer","null"]},"merchant_name":{"default":null,"description":"Label for an installment plan's merchant, 120 characters or fewer. Optional on installment_plan, ignored on every other type.","type":["string","null"]},"min_payment_order":{"default":null,"description":"Minimum-payment tie-break priority, 1 or more. Optional on every type. The minimum first pays any installment_plan's locked plan_payment_due in full, then the lowest-current-APR segment; this value only breaks a tie between segments sharing both the same current APR and the same installment-plan status.","type":["integer","null"]},"monthly_fee":{"default":null,"description":"Fixed fee charged each month while an installment plan's term is active, $0 or more and no greater than plan_payment_due. Optional on installment_plan. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"monthly_spend":{"default":null,"description":"Recurring monthly purchase amount posted to this segment before interest accrues, $0 to $50,000 per month. Optional on purchase. A negative value is rejected as NEGATIVE_BALANCE on every type. On every type other than purchase a positive value is rejected with FIELD_NOT_ALLOWED_HERE, since those balances do not accept new purchases; an explicit 0 is accepted.","type":["number","null"]},"plan_payment_due":{"default":null,"description":"Locked monthly payment for an installment plan, principal plus monthly_fee. Required on installment_plan, greater than $0, at least monthly_fee, and no more than $1,000,000,000. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"promo_expires_month":{"default":null,"description":"Month at which apr_pct flips to revert_apr_pct, 1 to 480. Required on balance_transfer and promotional. Ignored on purchase, cash_advance and installment_plan.","type":["integer","null"]},"remaining_payments":{"default":null,"description":"Payments left in an installment plan's stated term, 0 or more. Optional on installment_plan, ignored on every other type. 0 means the term has ALREADY ended and is valid with any balance, including a positive residual. From 1 up, the balance must be clearable within the stated term and must not be clearable a month early.","type":["integer","null"]},"revert_apr_pct":{"default":null,"description":"Rate this segment reverts to once its promo expires, 0 to 100, and at least apr_pct. Required on balance_transfer and promotional. Ignored on purchase and cash_advance. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate rather than repricing.","type":["number","null"]},"stop_spend_month":{"default":null,"description":"Month index at which recurring spend stops, 0 or more. Read on purchase only, and range checked on every type. Omit to spend for the whole projection.","type":["integer","null"]},"type":{"description":"Segment type. REQUIRED on every segment: omitting it is rejected. Per-type field matrix. Every field below is classified for every segment type: REQUIRED (omitting it is rejected), OPTIONAL (accepted either way and read), IGNORED (accepted and never read for this type, though a value can still fail the field's own range check), or REJECTED (supplying a disallowed value is an error; the field's own rule below says exactly which values are disallowed). Value rules are stated separately from applicability, because a field can be accepted on a type and still be restricted there. The validators are the authority; this matrix describes them.\n- type: REQUIRED on every type. Values: one of purchase, cash_advance, balance_transfer, promotional, installment_plan.\n- balance: REQUIRED on every type. Values: $0 to $1,000,000,000; above $50,000 returns a HIGH_CARD_BALANCE warning, not an error.\n- apr_pct: REQUIRED on purchase, cash_advance, balance_transfer, promotional; OPTIONAL on installment_plan. Values: 0 to 100 as a percentage, e.g. 24.99 not 0.2499. The REQUIRED classification above applies when balance is greater than 0; a zero-balance segment may omit it. Must be greater than 0 on cash_advance carrying a balance. Must equal 0 on installment_plan, where omitting it is the correct shape.\n- revert_apr_pct: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance; REJECTED on installment_plan. Values: 0 to 100, and at least apr_pct. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate.\n- promo_expires_month: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance, installment_plan. Values: 1 to 480.\n- monthly_fee: OPTIONAL on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: $0 or more, and no greater than plan_payment_due, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- plan_payment_due: REQUIRED on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: greater than $0, at least monthly_fee, and no more than $1,000,000,000, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- remaining_payments: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 0 or more. 0 means the stated term has ALREADY ended and is valid with any balance. From 1 up, balance must be clearable within the stated term.\n- min_payment_order: OPTIONAL on every type. Values: 1 or more; breaks a tie only between segments sharing both the same current APR and the same installment-plan status.\n- extra_payment_order: OPTIONAL on every type. Values: 0 or more; 0 means skip. Breaks a tie only between segments sharing the exact same current APR.\n- merchant_name: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 120 characters or fewer.\n- monthly_spend: OPTIONAL on purchase; REJECTED on cash_advance, balance_transfer, promotional, installment_plan. Values: $0 to $50,000 per month. A negative value is rejected as NEGATIVE_BALANCE on every type, purchase included. On every type other than purchase a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; an explicit 0 is accepted.\n- stop_spend_month: OPTIONAL on purchase; IGNORED on cash_advance, balance_transfer, promotional, installment_plan. Values: 0 or more; range checked on every type, read only on purchase.","type":"string"}},"required":["type","balance"],"type":"object"},"type":["array","null"]},"stop_spend_month":{"description":"Month index at which this card's recurring spend stops, 0 or more. Optional; omit to spend for the whole projection.","type":["integer","null"]}},"type":"object"},"type":"array"},"chart_title":{"default":null,"description":"Override for the chart title. Optional; must not contain an em dash or en dash. Max 120 characters.","type":["string","null"]},"extra_monthly_payment":{"default":null,"description":"Extra monthly payment in dollars, $0 to $1,000,000,000, applied on top of the required minimums. Optional; defaults to 0 when omitted.","type":["number","null"]},"fixed_payments":{"default":null,"description":"Whether to hold each card's payment constant for the whole payoff. Optional; defaults to false when omitted. When true, each card's payment is locked at max(cards[].minimum_payment, that card's issuer minimum computed at month 1), and the total monthly budget (those locked amounts plus extra_monthly_payment) is held constant for the whole payoff, so once a card is paid off its freed-up payment rolls forward onto the remaining cards. This is the ONLY mode in which cards[].minimum_payment affects calculate_cc_payoff's result; compare_strategies has no fixed_payments parameter and binds minimum_payment on both of its strategy arms regardless.","type":["boolean","null"]},"full_schedule":{"default":null,"description":"Whether to return the full per-card month-by-month schedule. Optional; defaults to false when omitted. The per-card monthly_schedule is capped at 1000 rows total across cards and months, so later months are omitted on a long multi-card payoff; the portfolio-level monthly_totals series is always complete and is the one to read for the whole timeline.","type":["boolean","null"]},"include_card_timeline":{"default":null,"description":"Whether to add the card_timeline block, a per-card view of when each card clears. Optional; defaults to false when omitted.","type":["boolean","null"]},"output":{"default":null,"description":"Response verbosity: 'summary' (default) | 'inline' | 'capture'. summary returns a compact response with a data_preview block; inline returns the full payload; capture writes the full payload to this server's local disk for the chart-render pipeline and returns a capture_ref URI. capture is available on the local stdio transport only, and the hosted HTTP transport rejects it with a structured error naming 'summary' and 'inline' as the valid alternatives, since a capture_ref would be a dead link for a remote caller. Optional; defaults to 'summary' when omitted.","type":["string","null"]},"per_segment":{"default":null,"description":"Whether each schedule row carries its per-segment breakdown. Optional; defaults to true when omitted.","type":["boolean","null"]},"strategy":{"default":null,"description":"Payoff order: 'avalanche' pays the highest APR first, 'snowball' the smallest balance first. Optional; defaults to 'avalanche' when omitted. Matched case-insensitively, and the response echoes the canonical lowercase form actually simulated.","type":["string","null"]},"windfalls":{"default":null,"description":"One-time principal payments, at most 12, e.g. a tax refund or a year-end bonus. Optional; a JSON null is treated as omitted. When non-empty the response gains baseline, with_windfalls, months_saved_vs_baseline, interest_saved_vs_baseline, windfalls_applied[] and windfalls_unused[]; an empty array returns the same shape as omitting it.","items":{"properties":{"amount":{"description":"Dollar amount of the windfall, greater than 0. Required per entry.","type":["number","null"]},"label":{"description":"Optional label for this windfall, e.g. 'Tax refund' or 'Year-end bonus'. Max 120 characters.","type":["string","null"]},"month":{"description":"Month index the windfall is applied, 0 or more. 0 means applied before month 1's interest; N >= 1 applies at the end of calendar month N. Required per entry.","type":["integer","null"]}},"type":["object","null"]},"type":["array","null"]}},"required":["cards"],"type":"object"}

before
{"properties":{"toolArguments":{"description":"JSON object with these parameters:\n\ngross_monthly_income: decimal > 0 (REQUIRED; OR provide annual_income instead)\nannual_income: decimal > 0 (alternative to gross_monthly_income; divided by 12)\nadditional_income: decimal >= 0 (optional, default 0; side income, rental income, bonuses. Monthly.)\n\nexisting_debts: array of debt objects (optional, can be empty):\n  - name: string (optional label, e.g. 'Car Loan')\n  - type: 'auto' | 'student' | 'credit_card' | 'personal' | 'mortgage' | 'heloc' | 'child_support' | 'other'\n  - monthly_payment: decimal > 0 (REQUIRED per debt)\n  - balance: decimal (optional; for payoff cost analysis in what-if scenarios)\n  - apr_pct: decimal 0-100 as PERCENTAGE (optional)\n  - months_remaining: int (optional; used for 10-month rule exclusion)\n\nproposed_debt: object (optional; OR use proposed_home_price instead):\n  - name: string (optional)\n  - type: 'auto' | 'student' | 'credit_card' | 'personal' | 'mortgage' | 'heloc' | 'child_support' | 'other' (optional, default 'mortgage')\n  - monthly_payment: decimal > 0 (REQUIRED)\n  - includes_tax_insurance: bool (optional, default true; if false and type is mortgage, warns that lenders use PITI)\n\nproposed_home_price: decimal > 0 (optional; auto-calculates full PITI. Cannot combine with proposed_debt.)\nproposed_down_payment_pct: decimal 0-99.9 as PERCENTAGE (optional, default 20)\nproposed_rate_pct: decimal 0-20 as PERCENTAGE (optional, default 7.0 with warning)\nproposed_term_years: int 1-40 (optional, default 30)\n\nproperty_tax_annual: decimal >= 0 (optional. For the PITI estimate, uses 0.88% national average if omitted)\nhome_insurance_annual: decimal >= 0 (optional. Uses 0.65% national average if omitted)\npmi_monthly: decimal >= 0 (optional. Auto-estimated at 0.5% of loan when LTV > 80%. Feeds the\n  conventional-basis PITI, so it moves with_proposed.front_end_dti, with_proposed.back_end_dti,\n  with_proposed.front_end_breakdown, the conventional qualification row, and\n  what_if.scenarios[].new_front_end_dti / new_back_end_dti. VA carries no PMI, and FHA/USDA always\n  compute their own upfront-plus-annual mortgage insurance instead, at every LTV, never this\n  override)\nhoa_monthly: decimal >= 0 (optional, default 0)\n\ninclude_what_if: bool (optional, default true; generate scenarios to improve DTI)\n\ntransaction_purpose: 'purchase' | 'refinance' | 'streamlined_assist' (optional, default 'purchase')\n  Affects USDA only, and only what is disclosed. USDA's 32% PITI and 44% Total Debt figures are\n  purchase-transaction waiver conditions (HB-1-3555 11.3.A.2), disclosed rather than applied as\n  ceilings: Senaro cannot observe how the file is underwritten, so a USDA ratio overage is never 'ineligible'\n  on any transaction purpose. For a refinance, 11.3.B states debt ratios 'are not limited to the\n  maximum purchase debt ratio thresholds', so where the note fires it names both figures and states that neither applies. Streamlined-assist\n  refinances require no debt ratio calculation at all. Conventional, FHA and VA are unaffected.\n\nfamily_size: int 1-20 (optional; must be supplied together with property_state, or neither fires)\nproperty_state: two-letter USPS state code, or 'DC'/'PR'/'GU'/'VI'/'AS'/'MP' (optional; must be supplied together with family_size)\n  Together these compute the VA residual income guideline (38 CFR 36.4340(e)) in\n  va_residual_income_guideline: the dollar amount VA's tables require for this family size, region,\n  and loan amount (derived from proposed_home_price; not computable without it), plus the 38 CFR\n  36.4340(c)(3) review-waiver figure. Computed only for family_size 1-7 and a property_state among\n  the 50 states, DC, or PR (not GU, VI, AS, or MP; 38 CFR 36.4340(e) assigns no region to those\n  four); outside those bounds, or without proposed_home_price, va_residual_income_guideline.status\n  reads 'not_computable' with the reason instead. This block alone is a LOOKUP, not a verdict: it\n  never compares against your actual residual income by itself.\n\nmonthly_taxes_and_retirement_withholding: decimal >= 0 (optional; your federal, state, and FICA tax\n  withholding, PLUS any amount paid or withheld for retirement, monthly. 38 CFR 36.4340(f)(13)\n  treats these as one class of deduction from gross income.)\nmonthly_maintenance_and_utilities: decimal >= 0 (optional; estimated monthly maintenance and utilities\n  for the proposed property. 38 CFR 36.4340 calls for a realistic estimate of this figure for the\n  property and local utility rates and sets no numeric multiplier itself, but VA underwriting\n  guidance (the Lender's Handbook, Pamphlet 26-7) publishes a per-square-foot multiplier for this\n  same estimate; applying it needs the property's square footage, which this tool does not\n  currently collect, so Senaro has no default to offer here and you supply the aggregate monthly\n  amount instead.)\n  Supplying BOTH of these, together with proposed_home_price and a computable family_size/\n  property_state above, computes qualification.va.residual_income_comparison: your ACTUAL monthly\n  residual income, its ratio to the va_residual_income_guideline figure, and whether\n  residual_income_meets_review_waiver_margin (residual income at or above 120% of the guideline) is\n  met. The shelter expense used here excludes any PMI (VA loans carry no monthly PMI; 38 CFR\n  36.4313(e) sets a funding fee instead, commonly financed into the loan -- see\n  va_funding_fee_financed_monthly below). 38 CFR 36.4340(c)(3)'s review-waiver condition is\n  CONJUNCTIVE: it also requires the back-end debt-to-income ratio (qualification.va.your_back_end)\n  to exceed 41%, which this field does not by itself confirm -- check both fields together. Even\n  when both hold, (c)(3) only WAIVES a second-level review requirement; it is not itself an\n  approval. Whether this file is actually approved is an underwriting determination Senaro does\n  not make and no input combination here determines. Missing any one of the needed inputs reads\n  qualification.va.residual_income_comparison.status 'not_computable' with every reason named.\nva_funding_fee_financed_monthly: decimal >= 0 (optional; the additional monthly payment from\n  financing a VA funding fee into the loan balance, if any. 38 CFR 36.4313(e)'s applicable\n  percentage depends on down payment, prior VA-loan use, and service category, none of which\n  Senaro collects, so there is no default; if omitted while any VA figure that depends on it is\n  produced -- qualification.va.your_back_end and its verdict, any what_if VA ratio,\n  what_if.max_affordable_home.va, or the residual-income comparison above -- a\n  VA_FUNDING_FEE_NOT_MODELED warning discloses that no fee is assumed. The home-price-reduction\n  what_if scenario's hypothetical price is fixed before the fee is considered, so a supplied fee\n  is scaled to that EXACT hypothetical loan size, since 38 CFR 36.4313(e)'s fee is a percentage\n  of loan principal. what_if.max_affordable_home.va is a two-pass approximation instead, so its\n  supplied fee is scaled to an ESTIMATE of the hypothetical loan size, not the exact figure\n  reported; the PMI, tax, and insurance reservation itself is an EXACT closed-form solve, so\n  only this fee-scaling step is approximate. Without proposed_home_price there is no reference\n  loan size to scale from either way, so the raw fee is reserved unscaled instead and a\n  VA_FUNDING_FEE_NOT_SCALED warning discloses it --\n  mutually exclusive with VA_FUNDING_FEE_NOT_MODELED by construction, since one requires the fee\n  omitted and the other requires it supplied.)"}},"required":["toolArguments"],"type":"object"}

after
{"properties":{"additional_income":{"default":null,"description":"Additional monthly income: side income, rental income, or bonuses. Optional; defaults to 0 when omitted. Must be zero or more.","type":["number","null"]},"annual_income":{"default":null,"description":"Annual gross income in dollars, divided by 12 to get monthly income. Exactly one of gross_monthly_income or annual_income is required. Must be at least $0.01, one cent, the smallest amount of money.","type":["number","null"]},"existing_debts":{"default":null,"description":"Existing debts to include in the DTI calculation. Optional; omit it or send an empty array for no existing debts. A JSON null is rejected; omit the field instead. At most 50 debts are allowed.","items":{"properties":{"apr_pct":{"description":"Annual percentage rate, as a percentage (0-100), e.g. 18.5 for 18.5%. Optional.","type":["number","null"]},"balance":{"description":"Current balance in dollars. Optional; used for payoff cost analysis in what-if scenarios.","type":["number","null"]},"monthly_payment":{"description":"Monthly payment in dollars. Required per debt; must be positive.","type":["number","null"]},"months_remaining":{"description":"Months remaining on this debt. Optional; used for the 10-month rule exclusion.","type":["integer","null"]},"name":{"description":"Optional label for this debt, e.g. 'Car Loan'.","type":["string","null"]},"type":{"description":"Debt type: 'auto', 'student', 'credit_card', 'personal', 'mortgage', 'heloc', 'child_support', or 'other'. Optional, defaults to 'other' when omitted; an unrecognized value warns rather than rejects.","type":["string","null"]}},"type":["object","null"]},"type":["array","null"]},"family_size":{"default":null,"description":"Household size for the VA residual income guideline. Supply family_size and property_state together, or neither. Optional; must be between 1 and 20.","type":["integer","null"]},"gross_monthly_income":{"default":null,"description":"Gross monthly income in dollars. Exactly one of gross_monthly_income or annual_income is required. Must be at least $0.01, one cent, the smallest amount of money.","type":["number","null"]},"hoa_monthly":{"default":null,"description":"Monthly homeowners association dues in dollars. Optional; defaults to 0 when omitted. Must be zero or more.","type":["number","null"]},"home_insurance_annual":{"default":null,"description":"Annual home insurance in dollars. Optional; if omitted, estimated at 0.65% of the proposed home price. Must be zero or more.","type":["number","null"]},"include_what_if":{"default":null,"description":"Whether to generate what-if scenarios showing how paying off a debt, increasing income, or reducing the home price would improve DTI. Optional; defaults to true when omitted.","type":["boolean","null"]},"monthly_maintenance_and_utilities":{"default":null,"description":"Estimated monthly maintenance and utilities for the proposed property. 38 CFR 36.4340 calls for a realistic estimate of this figure for the property and local utility rates and sets no numeric multiplier itself, but VA underwriting guidance (the Lender's Handbook, Pamphlet 26-7) publishes a per-square-foot multiplier for this same estimate. Applying it needs the property's square footage, which this tool does not currently collect, so Senaro has no default to offer here and you supply the aggregate monthly amount instead. Supplying BOTH this field and monthly_taxes_and_retirement_withholding, together with proposed_home_price and a computable family_size/property_state, computes qualification.va.residual_income_comparison: your ACTUAL monthly residual income, its ratio to the va_residual_income_guideline figure, and whether residual_income_meets_review_waiver_margin (residual income at or above 120% of the guideline) is met. The shelter expense used here excludes any PMI (VA loans carry no monthly PMI; 38 CFR 36.4313(e) sets a funding fee instead, commonly financed into the loan; see va_funding_fee_financed_monthly for the financed-fee field). 38 CFR 36.4340(c)(3)'s review-waiver condition is CONJUNCTIVE: it also requires the back-end debt-to-income ratio (qualification.va.your_back_end) to exceed 41%, which this field does not by itself confirm. Check both fields together. Even when both hold, (c)(3) only WAIVES a second-level review requirement; it is not itself an approval. Whether this file is actually approved is an underwriting determination Senaro does not make and no input combination here determines. Missing any one of the needed inputs reads qualification.va.residual_income_comparison.status 'not_computable' with every reason named. Optional; must be zero or more.","type":["number","null"]},"monthly_taxes_and_retirement_withholding":{"default":null,"description":"Your federal, state, and FICA tax withholding, plus any amount paid or withheld for retirement, monthly. 38 CFR 36.4340(f)(13) treats these as one class of deduction from gross income. Optional; must be zero or more.","type":["number","null"]},"pmi_monthly":{"default":null,"description":"Monthly PMI (private mortgage insurance) in dollars. Optional; if omitted, auto-estimated at 0.5% of the loan annually when loan-to-value exceeds 80%. Feeds the conventional-basis PITI, so it moves with_proposed.front_end_dti, with_proposed.back_end_dti, with_proposed.front_end_breakdown, the conventional qualification row, and what_if.scenarios[].new_front_end_dti and new_back_end_dti. VA carries no PMI, and FHA and USDA always compute their own upfront-plus-annual mortgage insurance instead, at every loan-to-value, never this override. Must be zero or more.","type":["number","null"]},"property_state":{"default":null,"description":"Two-letter USPS state code, or 'DC'/'PR'/'GU'/'VI'/'AS'/'MP'. Supply family_size and property_state together, or neither. Together these compute the VA residual income guideline (38 CFR 36.4340(e)) in va_residual_income_guideline: the dollar amount VA's tables require for this family size, region, and loan amount (derived from proposed_home_price; not computable without it), plus the 38 CFR 36.4340(c)(3) review-waiver figure. Computed only for family_size 1-7 and a property_state among the 50 states, DC, or PR (not GU, VI, AS, or MP; 38 CFR 36.4340(e) assigns no region to those four); outside those bounds, or without proposed_home_price, va_residual_income_guideline.status reads 'not_computable' with the reason instead. This block alone is a LOOKUP, not a verdict: it never compares against your actual residual income by itself. Optional.","type":["string","null"]},"property_tax_annual":{"default":null,"description":"Annual property tax in dollars. Optional; if omitted, estimated at 0.88% of the proposed home price. Must be zero or more.","type":["number","null"]},"proposed_debt":{"default":null,"description":"A proposed new debt, as an alternative to proposed_home_price. Provide at most one of proposed_debt or proposed_home_price; providing neither computes the current DTI only. Optional; a JSON null is treated as omitted, the same as leaving the field out.","properties":{"includes_tax_insurance":{"description":"Whether monthly_payment already includes tax and insurance. Optional, defaults to true when omitted; if false and type is 'mortgage', warns that lenders use full PITI for DTI.","type":["boolean","null"]},"monthly_payment":{"description":"Monthly payment in dollars. Required; must be positive.","type":["number","null"]},"name":{"description":"Optional label for this proposed debt.","type":["string","null"]},"type":{"description":"Debt type: 'auto', 'student', 'credit_card', 'personal', 'mortgage', 'heloc', 'child_support', or 'other'. Optional, defaults to 'mortgage' when omitted; an unrecognized value is rejected.","type":["string","null"]}},"type":["object","null"]},"proposed_down_payment_pct":{"default":null,"description":"Down payment as a percent of the proposed home price, e.g. 20 for 20%. Optional; defaults to 20 when omitted. Must be between 0 and 99.9 (100% cash purchases are not supported).","type":["number","null"]},"proposed_home_price":{"default":null,"description":"Proposed home purchase price in dollars. Provide at most one of proposed_debt or proposed_home_price; providing neither computes the current DTI only. Auto-calculates full PITI (principal, interest, taxes, insurance). Optional; must be at least $0.01, one cent, the smallest amount of money.","type":["number","null"]},"proposed_rate_pct":{"default":null,"description":"Proposed mortgage interest rate as a percent, e.g. 7.0 for 7.0%. Optional; the 7.0% default applies whenever this field is omitted, whether the proposal is proposed_debt or proposed_home_price. The default-rate warning fires only when proposed_home_price is used. Must be between 0 and 20.","type":["number","null"]},"proposed_term_years":{"default":null,"description":"Proposed mortgage term in years. Optional; defaults to 30 when omitted. Must be between 1 and 40.","type":["integer","null"]},"transaction_purpose":{"default":null,"description":"Mortgage transaction purpose: 'purchase', 'refinance', or 'streamlined_assist'. Optional, defaults to 'purchase' when omitted. Affects USDA only, and only what is disclosed. USDA's 32% PITI and 44% Total Debt figures are purchase-transaction waiver conditions (HB-1-3555 11.3.A.2), disclosed rather than applied as ceilings: Senaro cannot observe how the file is underwritten, so a USDA ratio overage is never 'ineligible' on any transaction purpose. For a refinance, 11.3.B states debt ratios 'are not limited to the maximum purchase debt ratio thresholds', so where the note fires it names both figures and states that neither applies. Streamlined-assist refinances require no debt ratio calculation at all. Conventional, FHA and VA are unaffected.","type":["string","null"]},"va_funding_fee_financed_monthly":{"default":null,"description":"The additional monthly payment from financing a VA funding fee into the loan balance, if any. 38 CFR 36.4313(e)'s applicable percentage depends on down payment, prior VA-loan use, and service category, none of which Senaro collects, so there is no default. If omitted while any VA figure that depends on it is produced, meaning qualification.va.your_back_end and its verdict, any what_if VA ratio, what_if.max_affordable_home.va, or qualification.va.residual_income_comparison, a VA_FUNDING_FEE_NOT_MODELED warning discloses that no fee is assumed. The home-price-reduction what_if scenario's hypothetical price is fixed before the fee is considered, so a supplied fee is scaled to that EXACT hypothetical loan size, since 38 CFR 36.4313(e)'s fee is a percentage of loan principal. what_if.max_affordable_home.va is a two-pass approximation instead, so its supplied fee is scaled to an ESTIMATE of the hypothetical loan size, not the exact figure reported; the PMI, tax, and insurance reservation itself is an EXACT closed-form solve, so only this fee-scaling step is approximate. Without proposed_home_price there is no reference loan size to scale from either way, so the raw fee is reserved unscaled instead, and a VA_FUNDING_FEE_NOT_SCALED warning discloses it. This is mutually exclusive with VA_FUNDING_FEE_NOT_MODELED by construction, since one requires the fee omitted and the other requires it supplied. Optional; must be zero or more.","type":["number","null"]}},"type":"object"}

before
{"properties":{"toolArguments":{"description":"JSON object with these parameters:\n\ncards (REQUIRED array, max 20):\n  - name: string (optional)\n  - purchase_balance: decimal >= 0 (REQUIRED)\n  - purchase_apr_pct: decimal 0-100 as percentage, e.g. 22.99 (REQUIRED)\n  - cash_advance_balance: decimal >= 0 (optional, default 0)\n  - cash_advance_apr_pct: decimal > 0, <= 100 (required if cash_advance_balance > 0)\n  - minimum_payment: decimal >= 0 (optional, 0 = auto-calculate). Used as the locked floor for the constant keep-cards payment: each card pays max(your minimum, the bank minimum), held constant and rolled forward as cards clear.\n  - segments: NOT SUPPORTED by this tool (rejected with a parse_error if supplied). This tool always reads the flat purchase_balance / cash_advance_balance fields above, never segments[] balances; supply those instead. segments[] input is supported by calculate_cc_payoff and compare_strategies.\n  - monthly_spend / stop_spend_month: NOT SUPPORTED by this tool (rejected with a validation error if supplied). Ongoing spend on cards a consolidation loan or transfer just paid off is not modeled by any arm here; supported by calculate_cc_payoff and compare_strategies.\n\nconsolidation_loan (REQUIRED object):\n  - annual_rate_pct: decimal 0-36 as percentage, e.g. 10.99 (REQUIRED)\n  - term_months: int 12-84 (REQUIRED)\n  - origination_fee_pct: decimal 0-10 (optional, default 0)\n  - origination_fee_flat: decimal (optional, default 0, takes precedence if > pct-based fee)\n  - include_fee_in_principal: bool (optional, default true)\n\nextra_monthly_payment: decimal >= 0 (optional, default 0)\ncurrent_strategy: 'avalanche' | 'snowball' (optional, default 'avalanche')\n(Note: fixed_payments is NOT a parameter of this tool, unlike calculate_cc_payoff. The keep-cards baseline is always simulated under the canonical constant rolled-forward payment, see comparison_basis in the response. Passing fixed_payments returns an unknown_parameter error.)\n\nBalance transfer, SINGLE OFFER (legacy, all optional):\ninclude_balance_transfer: bool (default false)\nbt_apr_pct: decimal 0-100 (required if include_balance_transfer: true, use 0 for 0% promo)\nbt_promo_months: int 1-60 (optional, default 18)\nbt_regular_apr_pct: decimal 0-100 (optional, default 25.20)\nbt_fee_pct: decimal 0-10 (optional, default 3.0)\n\nBalance transfer, MULTI-OFFER (preferred when comparing two or more offers):\nbt_offers: array of objects (max 10), when supplied, takes precedence over the scalar bt_* fields\n  Each object:\n  - apr_pct: decimal 0-100 (REQUIRED)\n  - promo_months: int 1-60 (optional, default 18)\n  - regular_apr_pct: decimal 0-100 (optional, default 25.20)\n  - fee_pct: decimal 0-10 (optional, default 3.0)\n  - label: string (optional, defaults to \"<apr_pct>% / <months>mo\")\nThe response includes a balance_transfer_offers block with per-offer simulation\nresults, selected_offer_index, selected_offer_label, selected_offer_reason, and all_offers_trap.\n\nPartial balance transfer (use when the BT offer has a transfer limit < your total debt):\nbt_transfer_limit: decimal >= 0.01 (optional), cap on total transferred amount.\n  When set, only this amount moves to the BT card; remaining balances stay on original cards.\n  A combined simulation runs both halves together, correctly redistributing freed minimum payments.\n  When omitted, the entire balance is transferred (legacy behavior).\nbt_transfer_strategy: 'highest_apr_first' | 'highest_balance_first' | 'manual' (optional, default 'highest_apr_first')\n  highest_apr_first: transfer from highest-APR segments first (maximizes interest savings)\n  highest_balance_first: transfer largest balances first\n  manual: use bt_manual_transfers to specify exact amounts per card\nbt_manual_transfers: array of objects (required when bt_transfer_strategy='manual')\n  Each object:\n  - card_name: string (must match a card name in cards[])\n  - amount: decimal > 0\n\nfull_schedule: bool (optional, default false, compact schedule by default)\n\nwindfalls: array of one-time principal payments (optional, default empty, max 12). Same shape as calculate_cc_payoff. Each item:\n  - month: int >= 0 (REQUIRED). 0 means applied before month 1's interest. N >= 1 applies at the END of calendar month N.\n  - amount: decimal > 0 (REQUIRED).\n  - label: string (optional). e.g. 'Tax refund', 'Year-end bonus'.\nWhen non-empty the response adds windfalls_applied[] and windfalls_unused[] on keep_cards, on each balance_transfer scenario (and on each offer in balance_transfer_offers.offers[]), on consolidation_loan (single-row per windfall since the loan is a single-balance instrument), and on optimized_consolidation.keep_subset. All scenarios use with-windfalls totals so cross-option ranking stays apples-to-apples.\n\nchart_title: string (optional) override for the chart title. Must not contain em-dashes or en-dashes. Max 120 characters.\n\nENVELOPE:\n  output: 'summary' (default) | 'inline' | 'capture'\n  summary: compact response with a data_preview block. No heavy array exists on this response today, so summary and inline are currently identical in content; the envelope is wired ahead of the future chart-render pipeline.\n  inline: full payload (currently identical to summary; will diverge once a heavy array is added for chart rendering).\n  capture: full payload written to ~/.senaro/captures/; capture_ref URI returned.\n    Available on the local stdio transport only; the hosted HTTP transport rejects 'capture'\n    with a structured error naming 'summary' and 'inline' as the valid alternatives."}},"required":["toolArguments"],"type":"object"}

after
{"properties":{"bt_apr_pct":{"default":null,"description":"Balance-transfer APR as a percentage, 0-100, e.g. 0 for a 0% promo. Required when include_balance_transfer is true and bt_offers is omitted. bt_offers, when supplied, overrides this and the other three bt_* scalars below. The 0-100 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["number","null"]},"bt_fee_pct":{"default":null,"description":"Balance-transfer fee as a percentage of the transferred balance, 0-10. Optional; defaults to 3.0 when omitted. bt_offers, when supplied, overrides this. The 0-10 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["number","null"]},"bt_manual_transfers":{"default":null,"description":"Exact per-card transfer amounts. Required when bt_transfer_strategy is 'manual'; each entry's card_name must match a name in cards[]. Optional otherwise; a JSON null is treated as omitted, the same as leaving the field out.","items":{"properties":{"amount":{"description":"Dollar amount to transfer from this card, greater than $0, up to $1,000,000,000. Required per entry.","type":["number","null"]},"card_name":{"description":"Card name; must match a name in cards[]. Required per entry. Max 120 characters.","type":["string","null"]}},"type":["object","null"]},"type":["array","null"]},"bt_offers":{"default":null,"description":"Balance-transfer offers to compare head-to-head, 1 to 10, preferred over the four scalar bt_* fields above when comparing two or more offers: when supplied, bt_offers overrides bt_apr_pct, bt_promo_months, bt_regular_apr_pct, and bt_fee_pct, and their range checks are skipped. The response includes a balance_transfer_offers block with per-offer simulation results, selected_offer_index, selected_offer_label, selected_offer_reason, and all_offers_trap. Optional; a JSON null is rejected, unlike bt_manual_transfers and windfalls below, where a JSON null is treated as omitted.","items":{"properties":{"apr_pct":{"description":"Offer APR as a percentage, 0-100, e.g. 0 for a 0% promo. Required per offer.","type":["number","null"]},"fee_pct":{"description":"Balance-transfer fee for this offer, as a percentage of the transferred balance, 0-10. Optional; defaults to 3.0 when omitted.","type":["number","null"]},"label":{"description":"Label for this offer. Optional; defaults to '<apr_pct>% / <promo_months>mo' when omitted. Max 120 characters.","type":["string","null"]},"promo_months":{"description":"This offer's promo period in months, 1-60. Optional; defaults to 18 when omitted.","type":["integer","null"]},"regular_apr_pct":{"description":"APR that applies after this offer's promo period ends, as a percentage, 0-100. Optional; defaults to 25.20 when omitted.","type":["number","null"]}},"type":["object","null"]},"type":["array","null"]},"bt_promo_months":{"default":null,"description":"Balance-transfer promo period in months, 1-60. Optional; defaults to 18 when omitted. bt_offers, when supplied, overrides this. The 1-60 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["integer","null"]},"bt_regular_apr_pct":{"default":null,"description":"APR that applies after the promo period ends, as a percentage, 0-100. Optional; defaults to 25.20 when omitted. bt_offers, when supplied, overrides this. The 0-100 range applies only when include_balance_transfer is true and bt_offers is omitted; a non-number is rejected in every case.","type":["number","null"]},"bt_transfer_limit":{"default":null,"description":"Cap on the total dollar amount transferred to the balance-transfer card, at least $0.01. When set, only this amount moves to the BT card; remaining balances stay on original cards, and a combined simulation runs both halves together, correctly redistributing freed minimum payments. Optional; when omitted, the entire balance is transferred (legacy behavior). Needs include_balance_transfer or bt_offers.","type":["number","null"]},"bt_transfer_strategy":{"default":null,"description":"How to choose which balances move when bt_transfer_limit is less than your total debt: 'highest_apr_first' (transfer from highest-APR segments first, maximizes interest savings), 'highest_balance_first' (transfer largest balances first), or 'manual' (use bt_manual_transfers to specify exact amounts per card). Optional; defaults to 'highest_apr_first' when omitted. Needs bt_transfer_limit.","type":["string","null"]},"cards":{"description":"Credit cards to include, 1 to 20. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"cards must be a JSON array.\"); the two are not the same rejection. segments and stop_spend_month are not supported by this tool and are rejected; a non-zero monthly_spend, annual_fee, or plan_fees_monthly is rejected too, but zero (including an explicit 0) is accepted and dropped for all three: this tool always reads the flat purchase_balance / cash_advance_balance fields on each card below, never segments[] balances, and card-level fees and ongoing spend are not modeled here. Those five fields are supported by calculate_cc_payoff and compare_strategies instead.","items":{"properties":{"cash_advance_apr_pct":{"description":"Cash advance APR as a percentage, greater than 0, up to 100. Required when cash_advance_balance is greater than 0.","type":["number","null"]},"cash_advance_balance":{"description":"Cash advance balance in dollars, $0 to $1,000,000,000. Optional; defaults to 0 when omitted.","type":["number","null"]},"minimum_payment":{"description":"Minimum payment in dollars, $0 to $1,000,000,000. Optional; 0 or omitted auto-calculates the bank minimum. Used as the locked floor for the constant keep-cards payment: each card pays max(your minimum, the bank minimum), held constant and rolled forward as cards clear.","type":["number","null"]},"name":{"description":"Card label, e.g. 'Chase Sapphire'. Optional; a card without a name is auto-numbered ('Card 1', 'Card 2', ...). Max 120 characters.","type":["string","null"]},"purchase_apr_pct":{"description":"Purchase APR as a percentage, 0-100, e.g. 22.99. Required per card.","type":["number","null"]},"purchase_balance":{"description":"Purchase balance in dollars, $0 to $1,000,000,000. Required per card.","type":["number","null"]}},"type":"object"},"type":"array"},"chart_title":{"default":null,"description":"Override for the chart title. Optional; must not contain an em dash or en dash. Max 120 characters.","type":["string","null"]},"consolidation_loan":{"description":"Loan terms for the consolidation option. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"consolidation_loan must be an object.\"); the two are not the same rejection.","properties":{"annual_rate_pct":{"description":"Annual interest rate for the consolidation loan, as a percentage, 0-36, e.g. 10.99. Required.","type":["number","null"]},"include_fee_in_principal":{"description":"Whether the origination fee is rolled into the loan principal rather than paid upfront. Optional; defaults to true when omitted. A JSON null is rejected; omit the field instead of sending null.","type":["boolean","null"]},"origination_fee_flat":{"description":"Flat-dollar origination fee, $0 to $10,000. Optional; defaults to 0 when omitted, and takes precedence over origination_fee_pct when it produces a larger fee. A JSON null is rejected; omit the field instead of sending null.","type":["number","null"]},"origination_fee_pct":{"description":"Origination fee as a percentage of loan principal, 0-10. Optional; defaults to 0 when omitted. A JSON null is rejected, unlike every other optional field on this tool; omit the field instead of sending null.","type":["number","null"]},"term_months":{"description":"Consolidation loan term in months, 12-84. Required.","type":["integer","null"]}},"type":"object"},"current_strategy":{"default":null,"description":"Your current payoff strategy, compared against the consolidation loan / balance-transfer alternative: 'avalanche' or 'snowball'. Optional; defaults to 'avalanche' when omitted. Case-sensitive.","type":["string","null"]},"extra_monthly_payment":{"default":null,"description":"Extra monthly payment in dollars, $0 to $1,000,000,000, applied on top of the required minimums. Optional; defaults to 0 when omitted. fixed_payments is not a parameter of this tool, unlike calculate_cc_payoff: the keep-cards baseline is always simulated under the canonical constant rolled-forward payment (see comparison_basis in the response); supplying fixed_payments returns an unknown_parameter error.","type":["number","null"]},"full_schedule":{"default":null,"description":"Whether to return the full month-by-month amortization schedule instead of the compact default. Optional; defaults to false when omitted.","type":["boolean","null"]},"include_balance_transfer":{"default":null,"description":"Whether to run a single-offer balance-transfer scenario using the four scalar bt_* fields below. Optional; defaults to false when omitted. Ignored once bt_offers is supplied; use bt_offers when comparing two or more offers.","type":["boolean","null"]},"output":{"default":null,"description":"Response verbosity: 'summary' (default) | 'inline' | 'capture'. summary: compact response with a data_preview block; no heavy array exists on this response today, so summary and inline are currently identical in content. inline: full payload (currently identical to summary; will diverge once a heavy array is added for chart rendering). capture: full payload written to this server's local disk for the chart-render pipeline; capture_ref URI returned. Available on the local stdio transport only; the hosted HTTP transport rejects 'capture' with a structured error naming 'summary' and 'inline' as the valid alternatives. Optional; defaults to 'summary' when omitted.","type":["string","null"]},"windfalls":{"default":null,"description":"One-time principal payments, at most 12, same shape as calculate_cc_payoff. Optional; a JSON null is treated as omitted, the same as leaving the field out. When non-empty, the response adds windfalls_applied[] and windfalls_unused[] on keep_cards, on each balance_transfer scenario (and on each offer in balance_transfer_offers.offers[]), on consolidation_loan (single-row per windfall since the loan is a single-balance instrument), and on optimized_consolidation.keep_subset. All scenarios use with-windfalls totals so cross-option ranking stays apples-to-apples.","items":{"properties":{"amount":{"description":"Dollar amount of the windfall, greater than 0. Required per entry.","type":["number","null"]},"label":{"description":"Optional label for this windfall, e.g. 'Tax refund' or 'Year-end bonus'. Max 120 characters.","type":["string","null"]},"month":{"description":"Month index the windfall is applied, 0 or more. 0 means applied before month 1's interest; N >= 1 applies at the end of calendar month N. Required per entry.","type":["integer","null"]}},"type":["object","null"]},"type":["array","null"]}},"required":["cards","consolidation_loan"],"type":"object"}

before
{"properties":{"toolArguments":{"description":"JSON object with these parameters:\n\ncards (REQUIRED array, max 20): same format as calculate_cc_payoff\n  - name, purchase_balance, purchase_apr_pct (REQUIRED)\n  - cash_advance_balance, cash_advance_apr_pct (optional)\n  - minimum_payment (OPTIONAL, omit or 0 to auto-calculate)\n  - annual_fee: decimal >= 0 (optional, default 0). Charged at month 1 and every 12th month thereafter.\n  - plan_fees_monthly: decimal >= 0 (optional, default 0). Charged every month while the card has a balance.\n  - segments: array (OPTIONAL; when present, supersedes purchase_balance / cash_advance_balance). Max 100 segments total across all cards in the request. Per-card, per-type caps: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan. Same per-segment shape as calculate_cc_payoff; see that tool's segments[] documentation for the full field list.\n\nextra_monthly_payment: decimal >= 0 (optional, default 0)\n(Note: fixed_payments is NOT a parameter of this tool, unlike calculate_cc_payoff. Avalanche and snowball are always compared under the canonical constant rolled-forward payment, see comparison_basis in the response. Passing fixed_payments returns an unknown_parameter error.)\napply_rate_cap: bool (optional, default false)\nchart_title: string (optional) override for the chart title. Must not contain em-dashes or en-dashes. Max 120 characters.\noutput: 'summary' | 'inline' | 'capture' (optional, default 'summary')\n  'capture' is available on the local stdio transport only; the hosted HTTP transport rejects it with a structured error naming 'summary' and 'inline' as the valid alternatives."}},"required":["toolArguments"],"type":"object"}

after
{"properties":{"apply_rate_cap":{"default":null,"description":"Whether to cap each card's APR at the regulatory ceiling before simulating. Optional; defaults to false when omitted.","type":["boolean","null"]},"cards":{"description":"Credit cards to compare, 1 to 20, the same shape calculate_cc_payoff takes. Required: omitting the field answers contract_error MISSING_REQUIRED_FIELD, while an explicit JSON null answers parse_error (\"cards is required and must be an array.\"); the two are not the same rejection. Every card may carry segments[]. Max 100 segments total across all cards in the request. Per-card, per-type caps: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan.","items":{"properties":{"annual_fee":{"description":"Annual fee in dollars, $0 to $1,000,000,000. Optional; defaults to 0. Charged at month 1 and every twelfth month after, while the card carries a balance.","type":["number","null"]},"cash_advance_apr_pct":{"description":"Cash advance APR as a percentage, greater than 0 and up to 100. Required when cash_advance_balance is greater than 0: cash advances have no promotional 0% product, so a 0% rate on a real advance balance is a data-entry error.","type":["number","null"]},"cash_advance_balance":{"description":"Cash advance balance in dollars, $0 to $1,000,000,000. Optional; defaults to 0 when omitted. A POSITIVE value alongside a non-empty segments[] is rejected, the same way purchase_balance is. An explicit 0 is accepted.","type":["number","null"]},"minimum_payment":{"description":"Minimum payment in dollars, $0 to $1,000,000,000 (optional, omit or set 0 to auto-calculate). Where it binds, the card is locked at max(minimum_payment, that card's issuer minimum computed at month 1), and that locked amount is paid every month. On calculate_cc_payoff it binds ONLY when fixed_payments = true; on the DEFAULT path (fixed_payments = false) it is NOT used, because the plan recomputes each card's issuer minimum from its current balance every month, and the response discloses that as MINIMUM_PAYMENT_NOT_BINDING. On compare_strategies there is no fixed_payments parameter and supplying one is rejected: the avalanche and snowball arms ALWAYS run locked, so the value DOES bind and moves both arms, while the minimum-payments-only baseline always recomputes and ignores it, disclosed as MINIMUM_PAYMENT_NOT_BINDING_IN_BASELINE.","type":["number","null"]},"monthly_spend":{"description":"Recurring monthly purchase amount charged to this card's purchase balance before interest accrues, $0 to $50,000 per month. Optional; defaults to 0. Use the segment-level monthly_spend instead when supplying segments[].","type":["number","null"]},"name":{"description":"Card label, e.g. 'Chase Sapphire', 120 characters or fewer. Optional; a card without a name is auto-numbered ('Card 1', 'Card 2', and so on). Echoed into per-card results and warning text. A name over the cap is replaced in error field paths by a key built from its zero-based card index, written as '#0 (name over cap)', '#1 (name over cap)' and so on.","type":["string","null"]},"plan_fees_monthly":{"description":"Recurring monthly card fee in dollars, $0 to $1,000,000,000, e.g. a pay-over-time plan fee. Optional; defaults to 0. Charged every month while the card carries a balance.","type":["number","null"]},"purchase_apr_pct":{"description":"Purchase APR as a percentage, 0 to 100, e.g. 24.99 not 0.2499. Required when purchase_balance is greater than 0: an omitted APR would silently compute $0 interest.","type":["number","null"]},"purchase_balance":{"description":"Purchase balance in dollars, $0 to $1,000,000,000. Required unless segments[] carries at least one segment: an omitted purchase_balance would silently report a $0, 0-month payoff. Supplying a POSITIVE value alongside a non-empty segments[] is rejected, since the two would be competing sources for the same balance. An explicit 0 is accepted.","type":["number","null"]},"segments":{"description":"Per-segment breakdown of this card's balances. Optional; when it carries at least one segment it SUPERSEDES purchase_balance and cash_advance_balance, and a POSITIVE value in either of those is rejected. An empty segments[] is treated as absent, so purchase_balance is then required. At most 100 segments across the whole request. Per card, per type: 1 purchase, 1 cash_advance, 5 balance_transfer, 1 promotional, 10 installment_plan. Each item carries its own type, balance, rate and payment priority; see the type field on the item for the per-type field matrix.","items":{"properties":{"apr_pct":{"default":null,"description":"Annual percentage rate for this segment, 0 to 100, e.g. 24.99 not 0.2499. Required when balance is greater than 0 on purchase, cash_advance, balance_transfer and promotional. On cash_advance it must be greater than 0 whenever a balance is carried. Must be 0 on installment_plan, which uses monthly_fee instead, so omitting it there is the correct shape.","type":["number","null"]},"balance":{"description":"Segment balance in dollars, $0 to $1,000,000,000. REQUIRED on every segment type: an omitted balance would silently report a $0, 0-month payoff, so it is rejected instead. An explicit 0 is valid, for example a paid-off balance_transfer segment kept for schedule continuity.","type":"number"},"extra_payment_order":{"default":null,"description":"Extra-payment tie-break priority, 0 or more, where 0 means this segment never receives extra payment. Optional on every type, and the default for installment_plan. Only breaks a tie between segments sharing the exact same current APR, since the Credit CARD Act (TILA §164(b), 15 U.S.C. §1666c(b)) / 12 CFR 1026.53(a) always pays the highest-current-APR segment first regardless of this value.","type":["integer","null"]},"merchant_name":{"default":null,"description":"Label for an installment plan's merchant, 120 characters or fewer. Optional on installment_plan, ignored on every other type.","type":["string","null"]},"min_payment_order":{"default":null,"description":"Minimum-payment tie-break priority, 1 or more. Optional on every type. The minimum first pays any installment_plan's locked plan_payment_due in full, then the lowest-current-APR segment; this value only breaks a tie between segments sharing both the same current APR and the same installment-plan status.","type":["integer","null"]},"monthly_fee":{"default":null,"description":"Fixed fee charged each month while an installment plan's term is active, $0 or more and no greater than plan_payment_due. Optional on installment_plan. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"monthly_spend":{"default":null,"description":"Recurring monthly purchase amount posted to this segment before interest accrues, $0 to $50,000 per month. Optional on purchase. A negative value is rejected as NEGATIVE_BALANCE on every type. On every type other than purchase a positive value is rejected with FIELD_NOT_ALLOWED_HERE, since those balances do not accept new purchases; an explicit 0 is accepted.","type":["number","null"]},"plan_payment_due":{"default":null,"description":"Locked monthly payment for an installment plan, principal plus monthly_fee. Required on installment_plan, greater than $0, at least monthly_fee, and no more than $1,000,000,000. On every other type a positive value is rejected with FIELD_NOT_ALLOWED_HERE, while 0 and a negative value are accepted and dropped.","type":["number","null"]},"promo_expires_month":{"default":null,"description":"Month at which apr_pct flips to revert_apr_pct, 1 to 480. Required on balance_transfer and promotional. Ignored on purchase, cash_advance and installment_plan.","type":["integer","null"]},"remaining_payments":{"default":null,"description":"Payments left in an installment plan's stated term, 0 or more. Optional on installment_plan, ignored on every other type. 0 means the term has ALREADY ended and is valid with any balance, including a positive residual. From 1 up, the balance must be clearable within the stated term and must not be clearable a month early.","type":["integer","null"]},"revert_apr_pct":{"default":null,"description":"Rate this segment reverts to once its promo expires, 0 to 100, and at least apr_pct. Required on balance_transfer and promotional. Ignored on purchase and cash_advance. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate rather than repricing.","type":["number","null"]},"stop_spend_month":{"default":null,"description":"Month index at which recurring spend stops, 0 or more. Read on purchase only, and range checked on every type. Omit to spend for the whole projection.","type":["integer","null"]},"type":{"description":"Segment type. REQUIRED on every segment: omitting it is rejected. Per-type field matrix. Every field below is classified for every segment type: REQUIRED (omitting it is rejected), OPTIONAL (accepted either way and read), IGNORED (accepted and never read for this type, though a value can still fail the field's own range check), or REJECTED (supplying a disallowed value is an error; the field's own rule below says exactly which values are disallowed). Value rules are stated separately from applicability, because a field can be accepted on a type and still be restricted there. The validators are the authority; this matrix describes them.\n- type: REQUIRED on every type. Values: one of purchase, cash_advance, balance_transfer, promotional, installment_plan.\n- balance: REQUIRED on every type. Values: $0 to $1,000,000,000; above $50,000 returns a HIGH_CARD_BALANCE warning, not an error.\n- apr_pct: REQUIRED on purchase, cash_advance, balance_transfer, promotional; OPTIONAL on installment_plan. Values: 0 to 100 as a percentage, e.g. 24.99 not 0.2499. The REQUIRED classification above applies when balance is greater than 0; a zero-balance segment may omit it. Must be greater than 0 on cash_advance carrying a balance. Must equal 0 on installment_plan, where omitting it is the correct shape.\n- revert_apr_pct: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance; REJECTED on installment_plan. Values: 0 to 100, and at least apr_pct. Rejected on installment_plan with FIELD_NOT_ALLOWED_HERE: an expired plan's residual keeps its existing rate.\n- promo_expires_month: REQUIRED on balance_transfer, promotional; IGNORED on purchase, cash_advance, installment_plan. Values: 1 to 480.\n- monthly_fee: OPTIONAL on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: $0 or more, and no greater than plan_payment_due, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- plan_payment_due: REQUIRED on installment_plan; REJECTED on purchase, cash_advance, balance_transfer, promotional. Values: greater than $0, at least monthly_fee, and no more than $1,000,000,000, on installment_plan. On every other type a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; 0 and a negative value are accepted and dropped there.\n- remaining_payments: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 0 or more. 0 means the stated term has ALREADY ended and is valid with any balance. From 1 up, balance must be clearable within the stated term.\n- min_payment_order: OPTIONAL on every type. Values: 1 or more; breaks a tie only between segments sharing both the same current APR and the same installment-plan status.\n- extra_payment_order: OPTIONAL on every type. Values: 0 or more; 0 means skip. Breaks a tie only between segments sharing the exact same current APR.\n- merchant_name: OPTIONAL on installment_plan; IGNORED on purchase, cash_advance, balance_transfer, promotional. Values: 120 characters or fewer.\n- monthly_spend: OPTIONAL on purchase; REJECTED on cash_advance, balance_transfer, promotional, installment_plan. Values: $0 to $50,000 per month. A negative value is rejected as NEGATIVE_BALANCE on every type, purchase included. On every type other than purchase a POSITIVE value is rejected with FIELD_NOT_ALLOWED_HERE; an explicit 0 is accepted.\n- stop_spend_month: OPTIONAL on purchase; IGNORED on cash_advance, balance_transfer, promotional, installment_plan. Values: 0 or more; range checked on every type, read only on purchase.","type":"string"}},"required":["type","balance"],"type":"object"},"type":["array","null"]},"stop_spend_month":{"description":"Month index at which this card's recurring spend stops, 0 or more. Optional; omit to spend for the whole projection.","type":["integer","null"]}},"type":"object"},"type":"array"},"chart_title":{"default":null,"description":"Override for the chart title. Optional; must not contain an em dash or en dash. Max 120 characters.","type":["string","null"]},"extra_monthly_payment":{"default":null,"description":"Extra monthly payment in dollars, $0 to $1,000,000,000, applied on top of the required minimums. Optional; defaults to 0 when omitted.","type":["number","null"]},"output":{"default":null,"description":"Response verbosity: 'summary' (default) | 'inline' | 'capture'. summary returns the headline comparison with a data_preview block; inline returns the full payload; capture writes the full payload to this server's local disk for the chart-render pipeline and returns a capture_ref URI. capture is available on the local stdio transport only, and the hosted HTTP transport rejects it with a structured error naming 'summary' and 'inline' as the valid alternatives, since a capture_ref would be a dead link for a remote caller. Optional; defaults to 'summary' when omitted.","type":["string","null"]}},"required":["cards"],"type":"object"}