io.github.Invaro/opentax

Compute US federal BUSINESS-ENTITY tax from the same cited corpus: check-the-box entity classification, Form 1120 corporate income tax (§ 179/168(k)/174A/163(j)/DRD/NOL, § 250, GBC/FTC/BEAT), S-corp entity taxes, corporate estimates, the § 4501 buyback excise, AET and PHC taxes. Individual returns → calculate_tax. Unknown keys are rejected; unmodeled territory refuses loudly with the reason.

Compute US federal income tax for an ESTATE or TRUST (Form 1041): the § 1(e) compressed brackets and § 642(b) exemption. Input is taxable income before the exemption, after the §§ 651/661 distribution deduction. Retained capital gains refuse loudly (§ 1(h) trust breakpoints not modeled). Grantor trusts belong on the grantor's individual return via calculate_tax.

Compute US federal INDIVIDUAL income tax (or balance due if withholding is given) from a content-addressed corpus of cited rules. NEVER estimate tax yourself — call this, and report ONLY numbers returned by oracle calls made with the real facts (never hand-check or approximate a line the oracle can compute: your recalled parameters may be stale). Negative result = refund. Returns the answer, every assumption made, and hashes that let anyone re-verify the full derivation offline. Facts are grouped (filing, income, retirement, credits, …) — fill the groups that apply; unknown keys are rejected, and the engine names any missing fact the target needs. When source documents CONFLICT on a value, do not silently pick one: compute both branches, disclose the conflict and your choice; an interview/confirmation answer (rollover, conversion, taxable-amount screens) usually reflects taxpayer intent better than a payer form's box code — prefer it and disclose. That heuristic covers FACTS only: LEGAL classifications (qualifying child vs other dependent, filing status, SSTB) follow the statute's tests, not intake checkbox labels — a generic 'claim dependent credit' flag does not convert a qualifying child into an ODC dependent. TRANSCRIBE documented amounts as given even when they look anomalous (e.g. state withholding in a no-income-tax state): disclose the anomaly, never delete or 'correct' a documented number from outside knowledge. If you believe an oracle result is wrong, report the ORACLE's number and note your dissent — never substitute your own: the corpus is primary-source-verified and your recollection is not. Business entities → calculate_business_tax; estates/trusts → calculate_fiduciary_tax; § 152 dependency → determine_dependent.

Compute the COMPLETE Form 1040 bottom-line set in one call — the 17 lines that determine the return (1a, 9, 10, 11, 12e, 15, 16, 17 AMT, 19, 22, 23, 24, 25d, 27a, 28, 32, 33, 34/37), each whole-dollar rounded by the engine. Takes the SAME input as calculate_tax (prefer the documents block: transcribe W-2/1099-R/SSA-1099 boxes and dependent birth dates — SSA-1099s are first-class, box 5 and box 6 are summed for you; the tool derives ages, classifications, Part IV withholding, and penalties deterministically). Never assemble return lines by hand — this tool is the return. TRANSCRIPTION CONVENTIONS: (1) a PRIOR-YEAR Form 1040 in the file supplies CONTINUING conditions the current-year interview omits — the 'Someone can claim: You as a dependent' checkbox and the blindness boxes carry forward unless the current-year data contradicts them; (2) COMMUNITY PROPERTY: do NOT split income 50/50 between MFS spouses when they lived apart all year with no transfers (§ 66(a) allocates earned income to the earner) or when a written separation agreement ended the community — transcribe each document to its named earner; never invent a Form 8958 split the intake does not request; (3) bonus depreciation for assets placed in service 1/1-1/19/2025 is 40% (§ 168(k) pre-OBBBA phase-down; 100% only for property ACQUIRED after 1/19/2025).

Compose a STATE return's printed-form line set deterministically (2025 IL-1040 / VA 760 / CA 540 / NY IT-201 / PA-40 / NJ-1040 / OH IT 1040 / NC D-400 / GA 500 / MD 502 / MO-1040 / WI Form 1 / MN M1 / SC1040 / AL Form 40 / OR-40 / OK Form 511 / CT-1040 / KS K-40 / AR AR1000F / NM PIT-1 / NE 1040N / ID Form 40 / WV IT-140 / ME 1040ME / HI N-11, RI-1040, MT Form 2, DE PIT-RES, ND-1, VT IN-111) — correct line NUMBERS from the printed forms and whole-dollar rounding, with the state tax computed by the oracle targets internally. DE filing status 4 (married filing combined separate) is TWO returns on one form: pass filingStatus 'mfs' with deCombinedSeparate plus the deSpouse* column-A inputs, and each column gets its own $3,250 deduction and its own bracket climb. MT starts from FEDERAL TAXABLE INCOME and has no standard deduction, personal exemption or Social Security subtraction of its own, so mtFederalDeductions (federal Form 1040 lines 12e and 13b) is REQUIRED and the composer refuses without it; long-term capital gains are taxed separately at 3%/4.1% on the page 2 worksheet. NC and GA start from federalAGI: NC runs the AGI-tiered child deduction, the independent itemize-vs-standard selection, and the Bailey/military/SS auto-subtractions; GA FORCES itemizing for federal itemizers (pass gaFederalItemized), runs the per-spouse retirement exclusion and Low Income Credit targets, and caps total credits at the line 16 tax. PA is CLASS-BASED and NJ is CATEGORY-BASED: transcribe the pa*/nj* class-or-category fields (PA: Box 16 compensation, per-spouse loss classes; NJ: the line 15-26 category nets — a category loss is suppressed per the printed rule, and the composer runs the pension-exclusion, Worksheet H deduction-vs-credit, EITC/CTC/CDCC targets itself) — federalAGI is NOT the PA or NJ base. OH starts from federal AGI: pass federalAGI + ohBusinessIncome and the composer runs the Business Income Deduction, MAGI-tiered exemptions, and the Schedule of Credits ordering (retirement/senior/CDCC/exemption credits before the joint filing credit's line-11 base). Workflow: run compute_return first for the federal substrate, compute any state-specific components the citations describe (additions, subtractions, credits without targets — disclose each), then call this ONCE and report its line set VERBATIM. Never hand-assemble state line numbers: transposed lines on correct dollars are the dominant state error mode. ALWAYS pass taxableSocialSecurity and unemploymentCompensation when nonzero (VA/CA/NY subtractions are applied by the composer). ALWAYS transcribe the intake's state-specific block (e.g. ca_tax_return.ca_form540_schca: AB 5 employee-classification additions; va_sch_a fields; county/use-tax questions) — those fields drive composer inputs. For VA MFJ, pass vaYourVagi/vaSpouseVagi (the separate-VAGI worksheet) so the composer can run the Spouse Tax Adjustment worksheet itself. For MD, pass mdSubdivision (the mandatory county tax — line 28), mdEicQualifyingChild for the 50%/100%/45% EIC routing, and mdNetCapitalGainSubject from an agent-completed Form 502CG when FAGI exceeds $350,000; the composer runs the pension-exclusion, exemption-chart, CTC, poverty-credit, and local EIC/poverty worksheets itself. Maryland part-year returns (Form 502 line 12 proration) are not composed. For MO, split each income item per spouse (moFagiYou/moFagiSpouse etc. — Missouri combined returns compute a SEPARATE chart tax per spouse), pass the line 9/10 federal-tax amounts per the printed lists, and remember the NEW TY2025 100% capital-gains subtraction (moCapitalGainYou/Spouse); Kansas City/St. Louis 1% earnings taxes are separate city returns the composer does not produce. For WI, pass wiScheduleIAdjustments (IRC frozen at 12/31/2022 — post-2022 federal changes convert on Schedule I), wiCapitalGainSubtraction from Schedule WD (30%/60% LTCG exclusion), and note the Act 15 SB-16 retirement subtraction FORFEITS every credit — the composer enforces the forfeiture; compute both ways before electing it. For MN, remember the IRC is frozen at May 1, 2023 (2025 OBBBA items convert on Schedule M1NC → mnAdditions/mnSubtractions), pass mnSsAlternativeMethod when AGI exceeds the SS threshold (the composer takes the greater), mnAmt whenever M1MT preferences exist, and mnNetInvestmentIncome for the 1% NIIT; M1C/M1REF credit schedules are transcribed buckets. For SC, the base is FEDERAL TAXABLE INCOME — pass scFederalTaxableIncome (Form 1040 line 15 verbatim; a negative amount is preserved via subtraction line r), NOT federalAGI; pass scNetLtcgAfterLosses for the 44% LTCG deduction (net LT gains against ALL capital losses first), the per-person retirement/military/age-65 fields (military retirement is 100% deductible and REDUCES the same person's other two deductions — the composer handles the interplay), and federalEITC (the composer adds the 125% NONREFUNDABLE SC EITC into line 13 itself — never also put it in nonrefundableCredits); the 2025 state-tax addback for federal itemizers goes in scAdditions. For AL, the composer builds Alabama AGI from transcribed lines (alWages = W-2 Box 16, alOtherIncome, alTaxableRetirement* for the Schedule RS 65+ $6,000 exclusion — still $6,000 in 2026, HB388 died) — federalAGI is NOT the base; pass alFederalTaxPlusNiit (1040 line 22 + Form 8960) and alFederalRefundableCredits (EIC+ACTC+AOC+adoption+2439) for the UNLIMITED line 12 federal tax deduction, and remember overtime earned Jan-Jun 2025 is exempt and already out of Box 16. For OR, pass the federal-tax-worksheet components (orFederal1040Line22, orFederalPtc from 8962 line 24, orFederalAoc/orFederalRefundableAdoption — the EITC/ACTC are NOT subtracted) for the AGI-capped line 10 subtraction, taxableSocialSecurity (subtracted in full), or2024TaxLiability for the 9.863% kicker, and the Kids Credit inputs (orKidsUnder6 + addbacks); OBBBA tips/overtime/vehicle-interest are CLAIMED for Oregon via OR-ASC codes 390/391/392 in orSubtractions but added b… [10022 more characters not shown]

Determine whether ONE candidate person is the taxpayer's § 152 dependent — qualifying child or qualifying relative, including multiple-support agreements and the divorced-parents release — as a proof-backed yes/no with citations. Feed the result into calculate_tax's credits group (qualifyingChildren / otherDependents).

Determine whether a job is on the Treasury Tipped Occupation list (Treas. Reg. § 1.224-1, final Apr 2026) for the § 224 'no tax on tips' deduction. Fuzzy-matches the job name; returns the official listing (name, TTC code, category) or a definitive 'not listed'.

Fact-check a claimed dollar amount about tax law ('the 2026 MFJ standard deduction is $32,200', 'CTC is $2,000 per child') against the corpus. Returns verified / refuted (with the correct value and citation) / unknown. Never states a verdict it cannot ground.

Verify a claimed tax amount (yours, a user's, or another tool's) against the law. Returns verdict 'verified' or 'refuted' with the correct value. Use this as a self-check before presenting any tax number. Put asOf (and target, if any) INSIDE the facts object — e.g. facts: {..., "asOf": "2025-12-31"} — otherwise the claim is checked under today's law.

Compute the answer under every filing status for the same facts — e.g. to answer 'should we file jointly or separately?'. Statuses that need more facts report their error instead of guessing.

Get a tax rule in full: statutory citation with its verbatim excerpt, validity window, parameters, the formula and applicability guard (the rule IR — rules are data), the rules and facts it depends on, and its content hash. Use to quote and explain the actual law behind an answer. Pass asOf to see only the version in force on that date.

Find exact dollar amounts where one more cent of an input costs MORE than a cent of tax (marginal rate over 100%) — e.g. the EITC investment-income kill switch, CTC phase-out steps. Every probe is a real evaluation.

Discover every input the tax corpus understands: id, type, whether required, and its documented default. Call this if unsure what information to collect from the user.

Look up the current-law dollar amounts behind a question ('standard deduction', 'CTC phase-out threshold', 'tips deduction cap') with their statutory citations and validity windows. Use this to fact-check ANY tax number before stating it — your training data likely predates the OBBBA.

Full-text search over the encoded tax-law corpus ('kiddie tax', 'NIIT threshold', 'california renters credit'). Returns matching rules: id, title, statutory citation, effective window, and a verbatim excerpt of the law text. A hit means the engine computes this; zero hits means it is outside the corpus — say so rather than guessing. Follow up with explain_rule for a hit's full formula, or lookup_tax_parameter for its dollar amounts.