Verifiable US tax oracle for AI agents: cited, machine-checkable federal and state tax computation
Connect Remote server
claude mcp add --transport http opentax https://opentax.invaro.ai/mcp
{
"mcpServers": {
"opentax": {
"url": "https://opentax.invaro.ai/mcp"
}
}
}
{
"servers": {
"opentax": {
"type": "http",
"url": "https://opentax.invaro.ai/mcp"
}
}
}
Settings > Connectors > Add custom connector
URL: https://opentax.invaro.ai/mcp
Tools 17 found in our last check
calculate_taxCompute 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…
calculate_business_taxCompute 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.…
calculate_fiduciary_taxCompute 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…
determine_dependentDetermine 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 grou…
compute_state_returnCompose 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 / N…
compute_returnCompute the COMPLETE Form 1040 bottom-line set in one call — the lines that determine the return (1a, 9, 10, 11, 12e, 15, 16, 17 AMT, 19, 20, 22, 23, 24, 25d, 27a, 28, 32, 33, 34/37), each whole-dollar rounded by the engine, plus the modeled Schedule 3 credits (schedule3), in a…
compute_form_2210Form 2210 — the estimated tax underpayment penalty (26 U.S.C. § 6654) for tax years 2025-2027, composed from the printed form: Part I (the required annual payment: 90% of this year's tax, or 100% / 110% of last year's — pass priorYearTax and priorYearAGI in facts, or noPriorYear…
compute_form_4562Form 4562 — depreciation for an individual's businesses and rentals, tax years 2025-2027 (calendar year): § 179 expensing with the dollar limit, phase-out, married-filing-separately split, business income limitation and carryover; the § 168(k) special allowance (100% for propert…
verify_tax_claimVerify 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: {...,…
list_input_factsDiscover 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.
explain_ruleGet 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 answe…
find_tax_cliffsFind 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.
compare_filing_statusesCompute 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.
lookup_tax_parameterLook 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…
search_tax_rulesFull-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…
verify_factFact-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.
is_tipped_occupationDetermine 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'.
Details
| Endpoint | https://opentax.invaro.ai/mcp (Streamable HTTP) |
| Package | @invaro/[email protected] (NPM, stdio) |
| First published | 23 Jul 2026 |
| Last updated | 23 Jul 2026 |
| Registry name | io.github.Invaro/opentax |
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