Federal income tax: Claude skills backed by tested code
Analysis only. No tool in this server places orders, modifies custodian records or files returns. This server holds no client data: every figure arrives in the call and nothing is stored. Results are estimates over those figures, not a return and not tax advice.
What taxagent-federal computes
7 commands, every one callable over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
| Command | What it returns | What it needs |
|---|---|---|
calculate_federal | Ordinary tax, long-term gains stacked across the preferential bands, and the 3.8% surtax. | nothing required |
calculate_capgains | Where a gain falls across the 0/15/20 bands once it is stacked on ordinary income. | nothing required |
calculate_niit | 3.8% on the lesser of net investment income or the MAGI excess. | nothing required |
calculate_amt | Tentative minimum tax against regular tax, with the 50% exemption phase-out and preferential rates kept on gains. | nothing required |
calculate_qbi | Qualified business income, with the wage and property limit phasing in and the service-business phase-out. | nothing required |
calculate_loss | How much of a net capital loss is deductible now, and what carries forward. | nothing required |
get_federal_capabilities | Which calculators taxagent-federal exposes, what it will not compute, and the rule pack its figures are pinned to. | nothing required |
When to use it
US federal tax calculations over figures you supply. It holds no client data: every figure arrives in the call and nothing is stored.
Requests it answers:
- “What will I owe in federal tax on this income?”
- “What rate will my long-term capital gain be taxed at?”
- “Do I have to pay the 3.8% investment income surtax?”
- “Will the alternative minimum tax apply to me?”
- “How large is my section 199A deduction?”
- “How much of a capital loss can I deduct this year?”
- “What federal tax can this server actually compute?”
What it does not do
Named here because leaving it out is how an agent ends up asserting something the code never computed. Each line is the registry's own wording, not a summary of it.
- A return. AMT and the section 199A deduction are computed separately and are not folded into one liability.
- Credits, self-employment tax and the additional Medicare tax.
- State and local tax.
Where the figures come from
7 rules in the pack this server reads, each carrying its authority and legal effective date. The engines read from the pack, and a constant reappearing in the calculation path fails the build.
| Rule | Authority |
|---|---|
amt | IRC sections 55-56; Rev. Proc. 2025-32; OBBBA section 70107 |
capital_gain_brackets | IRC section 1(h); Rev. Proc. 2025-32 |
capital_loss_limit | IRC section 1211(b) |
niit | IRC section 1411 |
ordinary_brackets | IRC section 1; Rev. Proc. 2025-32 |
qbi | IRC section 199A; Rev. Proc. 2025-32; OBBBA section 70105 |
standard_deduction | IRC section 63(c); Rev. Proc. 2025-32 |
Scripted case coverage
10 of the 71 console cases call this server over JSON-RPC on every build, across 2 of the 15 client objectives the case inventory groups by: Business owner and entity and Know what a gain costs.
| Case | What it asks | What it shows | Outcome |
|---|---|---|---|
federal-estimate | What does $185,000 and a $50,000 gain cost? | Ordinary tax band by band, then the gain stacked on top of taxable income so it lands in the right preferential band. | completed |
federal-gain-splits | A gain that straddles the 0% and 15% bands | The gain is split across bands rather than taxed wholly at the rate its top dollar reaches. This is the error the legacy code made. | completed |
federal-niit-threshold | Surtax on the lesser of investment income or the MAGI excess | At $260,000 MAGI only $10,000 is over the threshold, so the 3.8% applies to that, not to the whole $45,000 of investment income. | completed |
federal-amt-bites | When the alternative minimum tax actually applies | Tentative minimum tax against regular tax, with the exemption phasing out at 50 cents per dollar over the threshold. | completed |
federal-amt-keeps-rates | AMT does not reprice long-term gains | A gain inside AMTI keeps its preferential rate. Taxing it at 26/28% would overstate the liability substantially. | completed |
federal-qbi-phase-in | The wage limit phasing in, not switching on | Above the threshold the wage limit applies in proportion to how far into the phase-in range the taxpayer is, not all at once. | completed |
federal-qbi-sstb | A service business past the phase-out | The same figures as a consultancy rather than a manufacturer: the applicable percentage falls to zero and the deduction goes with it. | completed |
federal-loss-limit | $12,000 of losses, $3,000 deductible | The annual limit and what carries forward, rather than deducting the whole loss against ordinary income. | completed |
federal-rejects-float | A figure that cannot be represented exactly is refused | Money is decimal. A value that would silently lose a fraction of a cent is rejected at the boundary rather than rounded quietly. | VALIDATION_FAILED |
federal-capabilities | What the server will not compute | The boundary stated by the server itself: no return, no credits, no state tax, and AMT and section 199A never folded together. | completed |
Questions it answers
What will I owe in federal tax on this income?
Ordinary tax, long-term gains stacked across the preferential bands, and the 3.8% surtax. Nothing is required to start: every input has a declared default the result reports. Call calculate_federal on taxagent-federal over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
What rate will my long-term capital gain be taxed at?
Where a gain falls across the 0/15/20 bands once it is stacked on ordinary income. Nothing is required to start: every input has a declared default the result reports. Call calculate_capgains on taxagent-federal over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
Do I have to pay the 3.8% investment income surtax?
3.8% on the lesser of net investment income or the MAGI excess. Nothing is required to start: every input has a declared default the result reports. Call calculate_niit on taxagent-federal over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
Will the alternative minimum tax apply to me?
Tentative minimum tax against regular tax, with the 50% exemption phase-out and preferential rates kept on gains. Nothing is required to start: every input has a declared default the result reports. Call calculate_amt on taxagent-federal over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
How large is my section 199A deduction?
Qualified business income, with the wage and property limit phasing in and the service-business phase-out. Nothing is required to start: every input has a declared default the result reports. Call calculate_qbi on taxagent-federal over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
How much of a capital loss can I deduct this year?
How much of a net capital loss is deductible now, and what carries forward. Nothing is required to start: every input has a declared default the result reports. Call calculate_loss on taxagent-federal over MCP. Every result carries the method it used, the rule pack it was pinned to, what is still missing and whether coverage was complete, for a licensed professional to review.
The other servers
- Estate and gift tax: Federal estate tax, gift exclusions and fiduciary income tax.
- Cross-border tax: Foreign earned income exclusion and foreign gift reporting.
- Business entity tax: Section 179 expensing and C corporation versus pass-through.
- Penalties and safe harbours: Late filing and payment penalties, and the estimated tax safe harbour.
- Municipal bonds: Municipal bond yields, market discount and premium amortization.
- State and local tax: The federal cap on deducting state and local tax.
- Portfolio lots and harvesting: Account-scope lot analysis: gain and loss, wash-sale screening, loss-harvest scenarios.
- Household and UMA coordination: Household and UMA-sleeve coordination over one shared budget per tax unit.