Agentic Indian income-tax advisor
Most “AI tax” tools let a language model do the arithmetic and hope. TaxBrainAI hands every number to a deterministic engine, grounds every claim in the statute, and runs a fail-closed verifier that would rather refuse than guess.
Live demo · try it
First a guided walkthrough of the agent — routing, retrieval, a human-approval gate, a cited answer. Then the deterministic tools below, running live in your browser: no login, no server call, matched to the engine to the rupee.
Pick a question below to watch the full pipeline light up stage by stage — routing, retrieval, the deterministic engine, the human-approval gate, then a cited answer. Or type your own at the bottom — it runs against the live backend.
See the live agent
The full agent — live retrieval, the model, and document tools — runs behind auth. Email to request access and I’ll set you up with a walkthrough, usually within 24 hours.
Replies usually within 24 hours.
What you’re watching
Scripted sessions that mirror the live agent (which runs against the FastAPI backend, behind auth).
These are the exact deterministic rules the agent calls, ported to run in your browser and checked against the engine’s test suite — so they cost nothing and work even if the server is down.
Income tax · AY 2026-27 · new vs old
Income
Capital gains & VDA
Deductions · old regime
You
AY 2026-27. Deductions and HRA apply under the old regime only (80CCD(2) also under the new). Everything else the engine takes is here; three specialist paths — the Section 112 land/building indexed lower-of, presumptive Sections 44AD/44ADA, and AMT (Section 115JC) — run in the full engine, open-sourced as taxbrainai-compute.
Saves ₹1,59,900 versus the old regime.
Computed in your browser — the same deterministic logic the agent calls, differential-tested against the Python engine to the rupee.
Statute lookup & 1961 → 2025 mapping
Search any section by number or by what it does — the same resolver the agent uses to turn a reference into a plain-English citation. Where the Income-tax Act, 2025 renumbers a section, the row also shows its new number, straight from the statute graph’s 1961↔2025 equivalence edges.
115BACNew tax regime (default)The default regime from AY 2024-25. Lower slab rates, but most deductions and exemptions no longer apply.
87ARebate for small incomesNew regime: up to ₹60,000 when total income is ≤ ₹12,00,000. Old regime: up to ₹12,500 when ≤ ₹5,00,000. Residents only.
2025 Act → Section 156 — Rebate of income-tax
16(ia)Standard deduction (salary)A flat deduction from salary — ₹75,000 under the new regime, ₹50,000 under the old.
2025 Act → Section 19 — Deductions from salaries
10(13A)House Rent Allowance (HRA)Exempts the least of: actual HRA, rent paid minus 10% of salary, or 50% of salary (metro) / 40% (non-metro). Old regime only.
2025 Act → Section 11 — Incomes not included in total income
10(10D)Life-insurance proceedsMaturity or death proceeds are exempt, subject to premium-to-cover limits — high-premium ULIPs (premium above ₹2,50,000) and other policies (above ₹5,00,000) are taxable.
2025 Act → Section 11 — Incomes not included in total income
24(b)Home-loan interestInterest on a housing loan. Self-occupied: up to ₹2,00,000 a year (old regime). New regime allows no interest on a self-occupied home; on a let-out home it is allowed but the loss can't be set off against other income.
2025 Act → Section 22 — Deductions from income from house property
80CInvestment deductionsUp to ₹1,50,000 for PPF, ELSS, life insurance, principal repayment, and more. Old regime only.
80CCD(1B)Extra NPS deductionAn additional ₹50,000 for NPS contributions, over and above the ₹1,50,000 Section 80C ceiling. Old regime only.
80CCD(2)Employer NPS contributionThe employer's NPS contribution — the one Chapter VI-A deduction still allowed under the new regime.
80DHealth insurance premiumPremium paid for self, family, and parents. Old regime only.
2025 Act → Section 126 — Health insurance premia
80DDDisabled-dependant careMaintenance and medical care of a disabled dependant — ₹75,000, or ₹1,25,000 for severe disability. A flat amount, regardless of spend. Old regime only.
2025 Act → Section 127 — Maintenance of a disabled dependant
80DDBTreatment of specified diseasesUp to ₹40,000 for prescribed serious illnesses, or ₹1,00,000 for a senior citizen. Old regime only.
2025 Act → Section 128 — Medical treatment
80UDisability (self)For a resident with a certified disability — ₹75,000, or ₹1,25,000 for severe disability. Old regime only.
2025 Act → Section 154 — Person with disability
80EEducation-loan interestThe full interest on a higher-education loan, for up to 8 years. No upper limit; old regime only.
80GDonationsDonations to approved funds and charities — 50% or 100%, some capped at 10% of income. Old regime only.
2025 Act → Section 133 — Donations to certain funds
80TTASavings-account interestInterest on savings deposits, up to ₹10,000. Old regime; not for senior citizens, who use 80TTB.
80TTBSenior-citizen deposit interestFor senior citizens — interest on savings and fixed deposits, up to ₹50,000. Old regime only.
111AShort-term capital gains · listed equity20% on STCG from listed shares and equity funds, for transfers on or after 23 July 2024.
2025 Act → Section 196 — Tax on short-term capital gains
112ALong-term capital gains · listed equity12.5% on LTCG above ₹1,25,000 a year from listed shares and equity funds.
2025 Act → Section 198 — Tax on long-term capital gains, certain cases
112Long-term capital gains · other assets12.5%. Land or building bought before 23 July 2024 may take the lower of 12.5% unindexed or 20% indexed.
2025 Act → Section 197 — Tax on long-term capital gains
54Rollover · sale of a houseLong-term gain on a residential house is exempt to the extent you buy or build another residential house within the prescribed windows.
2025 Act → Section 82 — Profit on sale of property used for residence
54FRollover · other asset into a houseLong-term gain on any asset other than a house is exempt if the net sale proceeds go into one residential house — proportionate if only part is invested.
54ECRollover · capital-gains bondsLong-term gain on land or a building is exempt if invested in NHAI / REC-type bonds within 6 months — capped at ₹50,00,000 a year.
115BBEUnexplained incomeUnexplained cash credits, investments or money (Sections 68–69D) are taxed at a flat 60%, plus surcharge and cess — no deduction, allowance or loss set-off allowed.
115BBHVirtual digital assetsA flat 30% on crypto and other VDA income. Only cost of acquisition is deductible; no loss set-off and no 87A rebate.
194STDS on VDA transfer1% tax deducted at source on the transfer of a virtual digital asset.
44ADPresumptive · businessIncome deemed at 6% of digital turnover and 8% of cash turnover. Turnover cap ₹2 crore, or ₹3 crore when cash receipts are ≤ 5%.
44ADAPresumptive · professionIncome deemed at 50% of gross receipts. Receipts cap ₹50 lakh, or ₹75 lakh when cash receipts are ≤ 5%.
44ABTax auditAccounts must be audited above ₹1 crore turnover (₹10 crore if cash is ≤ 5%) for business, or ₹50 lakh receipts for a profession.
194ATDS · interestTax deducted at source on interest other than on securities — e.g. bank or company deposit interest.
194CTDS · contractorsTax deducted at source on payments to contractors and sub-contractors.
194HTDS · commission / brokerageTax deducted at source on commission or brokerage.
194JTDS · professional feesTax deducted at source on fees for professional or technical services, and on royalty.
194TTDS · payments to partnersTax deducted at source on a firm's salary, remuneration, bonus, commission or interest paid to its partners. New from 1 April 2025.
139(1)Filing the returnThe core filing obligation and its due dates — 31 July for most individuals, 31 October where an audit applies.
2025 Act → Section 263 — Return of income
139(4)Belated returnA return filed after the due date, up to 31 December of the assessment year.
2025 Act → Section 263 — Return of income
139(5)Revised returnCorrecting an omission or error in a filed return, up to 31 December of the assessment year.
2025 Act → Section 263 — Return of income
139(8A)Updated return (ITR-U)File with additional tax up to 48 months after the end of the assessment year.
2025 Act → Section 263 — Return of income
139(9)Defective returnYour return is flagged as defective, with time given to correct it.
2025 Act → Section 263 — Return of income
234AInterest · late filing1% a month on unpaid tax, from the due date to the date of filing.
2025 Act → Section 423 — Interest, default in furnishing return
234BInterest · advance-tax shortfall1% a month on the shortfall when advance tax paid is too little.
2025 Act → Section 424 — Interest, default in advance tax
234CInterest · deferred advance tax1% a month for missing the quarterly advance-tax installment deadlines.
2025 Act → Section 425 — Interest, deferment of advance tax
234FLate-filing feeA flat ₹5,000, reduced to ₹1,000 when total income is ≤ ₹5,00,000.
2025 Act → Section 428 — Fee, default in furnishing return
89Relief on arrearsRelief when salary arrears or advance push you into a higher bracket — recomputed by spreading the income across the relevant years (Form 10E).
2025 Act → Section 157 — Relief for salary arrears
90DTAA reliefRelief from double taxation under a tax treaty with the other country — by exemption or foreign-tax credit.
91Foreign-tax relief (no treaty)Unilateral credit for foreign tax paid where India has no treaty with that country.
2025 Act → Section 160 — Countries with no agreement
143(1)Intimation after processingAn automated summary after your return is processed — a refund, a demand, or no change.
2025 Act → Section 270 — Assessment
142(1)Inquiry before assessmentA notice asking for information, or to file a return, before assessment.
2025 Act → Section 268 — Inquiry before assessment
148Income escaping assessmentA reassessment notice when the department believes income was not fully disclosed.
2025 Act → Section 280 — Income escaping assessment
148AProcedure before a 148 noticeThe mandatory inquiry and opportunity to explain before a Section 148 reassessment notice can be issued.
2025 Act → Section 281 — Procedure before a Section 280 notice
144BFaceless assessmentThe faceless, jurisdiction-free assessment procedure.
2025 Act → Section 273 — Faceless assessment
156Notice of demandA formal demand for tax, interest, or penalty payable.
2025 Act → Section 289 — Notice of demand
245Adjustment of refundNotice that a refund is being set off against an outstanding demand.
2025 Act → Section 438 — Set off and withholding of refunds
133(6)Call for informationThe department may require information relevant to an inquiry or proceeding.
2025 Act → Section 252 — Power to call for information
288A / 288BStatutory roundingTotal income (288A) and tax payable (288B) are each rounded to the nearest ₹10.
What it does
A compute engine, a knowledge graph, and guardrails it can’t talk its way around.
AY 2026-27 new-regime marginal relief, the Section 87A rebate, the July 2024 capital-gains cutover, indexed long-term gains, surcharge caps, and the 30% rate on virtual digital assets — computed exactly, not estimated.
Every figure and rule cites its section. The answer carries its receipts, so you — or your CA — can check it line by line.
Indian tax law is a web of cross-references. A graph stage follows the section-to-section links that flat vector search alone would miss.
Ask it something it can’t ground and it declines instead of hallucinating. “Never fabricate” is wired into the verifier, not left to the prompt.
Notice handling pauses at a LangGraph interrupt for human review, then resumes idempotently from its checkpoint.
PAN, Aadhaar, names, and identifiers are graded and redacted before they reach the model or the logs, with an audit trail on every request.
How it works · architecture
Two systems, one hand-off: the nine-node request graph — where the engine numbers and the statute citations converge at the Synthesizer — and the separate, offline build lifecycle that produces the fine-tuned model driving it. Click any node to expand its detail.
Classifies intent (qa · compute · planning · notice · reconcile · filing) and routes to tools. Scope safety runs first and is never delegated to the answering model: out-of-scope is refused by deterministic rules; jailbreak/unsafe is screened by a dedicated safety classifier (keyword guard offline · Llama Guard 4 live) — before anything runs.
The stack behind it
Ports & adapters everywhere: the core runs and is fully tested on deterministic mocks with zero API spend, then swaps to live providers behind one flag — numpy vectors → pgvector, a networkx graph → Neo4j, an in-memory checkpointer → a durable store, each behind the same port.
Measured & gated
A 200-question golden set drives development; the measured figures below are the run on a 366-row decontaminated held-out set (paired-bootstrap CI, Holm-corrected). The gate figures are hard pass/fail thresholds the run must clear — they are not accuracy scores. Graded axes are scored by the real-tier LLM-judge ensemble (two graders + an auditor).
Engineering
Every choice here buys something and pays for something. These are the ones I made on purpose.
Cost & performance
No invoice to quote — the interesting part is how it's engineered to stay cheap. Six decisions do the work.
Every tax figure is computed in code, never billed per token by an LLM. The arithmetic carries no per-query cost — and it's exact.
The calculator and statute lookup are the engine ported to client-side code. They execute on your device, so they add no server cost at all.
The model tier serves on demand with min-containers at zero: when no one is asking, nothing is running, so idle time bills nothing.
The model endpoint sits behind proxy-auth, so unauthenticated traffic can't spin up a GPU. Abuse can't quietly run up the bill.
A fine-tuned Gemma-4-E4B, served on demand, stands in for a frontier API on every call — capability where it's needed, without the per-token frontier price.
A max-containers cap bounds the worst case, and enforce-eager serving trims cold-start cost — so spend can't run away.
The deterministic tools are live and free on this page; the model tier serves behind auth with scale-to-zero ceilings — engineered to keep spend near-zero, not a running invoice.
Scorecard
Graph and test counts are read straight from the repository. The agent graph runs end to end on deterministic adapters today; the live model tier swaps in behind one flag.
1,488 sections and 4,707 edges, built from the Income-tax Acts of 1961 and 2025.
The Acts, the Income-tax Rules, Finance Acts, and CBDT circulars — chunked and indexed for retrieval.
Equivalence edges linking each old section to its counterpart in the new Act.
309 full-text judgments fetched from Indian Kanoon — court, date, and citation captured for each — forming the case-law corpus beside the statute index.
Property-tested, statute-grounded, and accurate to the rupee — and the load-bearing pieces are published, so you can verify them yourself: install the engine, plug in the MCP tools, or inspect the model card.
The deterministic engine behind this page, published as a standalone library — pure-Decimal, zero dependencies, 139 tests at 100% coverage (20 Hypothesis property invariants), cross-verified against all four Income-Tax Department e-filing utilities.
The engine exposed as 8 tools over the Model Context Protocol — deterministic tax computation and statute lookup in any MCP client. Published to PyPI and listed on the official MCP Registry as io.github.harshil-projects/taxbrainai-mcp.
The fine-tuned advisor-synthesis model (Gemma 4 E4B) that drives the Router and Synthesizer — released with the merged bf16 ship weights, all three LoRA adapters (SFT · DPO · GRPO), and a full training-and-eval model card.
The builder
TaxBrainAI is my work end to end — the agent graph, the deterministic engine, the fine-tune and its eval harness, and this page. I’m open to agentic-AI and backend roles.
Agentic Indian income-tax advisor — deterministic compute, statute-grounded answers, and a fail-closed verifier.
Educational demo — general guidance, not personal tax, legal, or financial advice. Verify with a qualified professional before filing.