Jock Taxes for ChatGPT

Calculate MLB tax

calculate_mlb_tax

Calculate professional-athlete tax for one MLB season with the Jock Taxes engine. Ask the user for a missing team or salary. Do not invent team codes, seasons, salaries, or filing status. Call list_tax_calculator_inputs for allowed values. Send salary when the user has one season total taxed entirely as duty-day pay. Send base_salary plus optional signing_bonus and performance_bonus to match the site Salary + Bonuses form. Do not send salary together with base_salary or a bonus. exempt_signing_bonus_from_jock_tax defaults to true for a split, so the signing bonus is taxed only in the player's domicile. performance_bonus is included only when include_performance_bonus_in_jock_tax is true. art_xvi4_inducement_sb applies to an exempt signing bonus paid by a Canadian club to a U.S. resident. Present the result as a calculation, not as tax or legal advice. Required before this call: team, and salary or base_salary. Match a player with list_team_players only after league, team, and season_id are known. Repeat inputs and defaults from the result in the reply. Results are income tax only unless the user asks for take-home: then send include_payroll_taxes, agent_fee_pct, retirement_contribution (401(k), or RRSP on a Canadian club) or rca_contribution (Canadian clubs), and report result.net_pay. Comparisons then match on net_pay.net_economic, which counts an RCA after its estimated payout tax (rca_payout_tax_rate; default 25% Canadian withholding on the US-duty-day share and the US federal marginal rate on the rest, or 25% on all of it for a US person).

Input Schema

Name	Required	Description
`team`	Yes	Team code, such as BOS.
`salary`	No	One season total in whole dollars, taxed entirely as duty-day pay. Leave this out when sending base_salary.
`season_id`	No	Schedule season as eight digits, such as 20252026. Defaults to the latest season for the league when omitted.
`base_salary`	No	Duty-day base in whole dollars before signing and performance bonuses. Send this with the bonus fields to match Salary + Bonuses. Leave it out when sending salary.
`agent_fee_pct`	No	Agent fee as a percent of gross pay (0-10), treated as a non-deductible cost. Default 0.
`birth_country`	No	Birth country code used with is_us_person.
`filing_status`	No	Single or Married_Joint. Defaults to Single when omitted.
`signing_bonus`	No	Signing bonus in whole dollars. The site adds this into the season total. On NFL it also includes other inducement pay.
`contract_season`	No	Contract season label, such as 2025-26.
`primary_domicile`	No	Resident tax home: a state, a city, or a mode such as local_jurisdiction. Defaults to local_jurisdiction when omitted.
`rca_contribution`	No	Salary deferred into a Retirement Compensation Arrangement by a Canadian club, in USD. Excluded from Canadian employment income until paid out: from worldwide income for a Canadian resident and in full from Canadian-source pay for a non-resident (Martin v. The King, 2024 TCC 153). US tax is unchanged. Not applied for US clubs. Comparisons count it after the estimated tax at payout (see rca_payout_tax_rate). Default 0.
`performance_bonus`	No	Performance bonus in whole dollars. Included in the total only when include_performance_bonus_in_jock_tax is true.
`rca_payout_tax_rate`	No	Estimated tax on the RCA when it is paid out, as a percent (0-100). Default models a player who retires to a no-tax US state and draws the RCA and its refundable tax account down at once: the US-duty-day share, already taxed by the US when contributed, bears Canada's 25% non-resident withholding, and the rest bears the US federal marginal rate on it (37% for a high earner). For a US person, who pays US tax on the whole contribution now, the default is the 25% withholding alone. Lowers net_pay.net_economic, which comparisons match on.
`retirement_catch_up`	No	none (default), 50_plus (+$8,000) or 60_to_63 (+$11,250). Catch-up contributions are always Roth for athletes (prior-year FICA wages over $150,000).
`include_payroll_taxes`	No	Opt in to employee payroll taxes for each team's employer: FICA (Social Security, Medicare, Additional Medicare) and the home state's disability or paid-leave levy for US clubs; CPP/QPP, EI and QPIP for Canadian clubs. Default false. For a Canadian resident it also applies the CPP/QPP and EI credits and the enhanced CPP/QPP deduction on the Canadian return. With any take-home option set, the response adds net_pay (net = cash take-home, net_economic = net plus the 401(k) deferral), agent_fee, retirement_contribution, and payroll_taxes when payroll is on. amounts.total stays income tax only.
`art_xvi4_inducement_sb`	No	Opt in to Canada–U.S. Treaty Art. XVI(4) on an exempt signing bonus from a Canadian club.
`estimated_playoff_games`	No	Extra postseason games. Use 0 when there are none.
`retirement_contribution`	No	Annual retirement contribution in USD. On a US club it is a 401(k) elective deferral capped at the 2026 limit ($24,500 plus catch-up). On a Canadian club it is an RRSP contribution capped at C$33,810, deducted from Canadian taxable income only. Default 0.
`retirement_contribution_type`	No	401(k) only: pretax (default) lowers income-tax wages except in Pennsylvania, Philadelphia, Pittsburgh, Ohio cities, Kansas City and St. Louis; roth lowers nothing. RRSP contributions are always deductible.
`exempt_signing_bonus_from_jock_tax`	No	When true, the signing bonus is taxed in the player's domicile and left out of duty-day allocation.
`include_performance_bonus_in_jock_tax`	No	When true, performance_bonus is part of the season total and of duty-day pay.

Output Schema

Name	Required	Description	Default
`sport`	Yes
`inputs`	Yes
`result`	Yes
`defaults`	Yes
`disclaimer`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed7 schema fields changedOct 26, 2026

addedInput schema / properties / agent_fee_pct

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Agent fee as a percent of gross pay (0-10), treated as a non-deductible cost. Default 0.",
+  "title": "Agent Fee Pct"
+}

addedInput schema / properties / include_payroll_taxes

Added value: +{
+  "anyOf": [
+    {
+      "type": "boolean"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Opt in to employee payroll taxes for each team's employer: FICA (Social Security, Medicare, Additional Medicare) and the home state's disability or paid-leave levy for US clubs; CPP/QPP, EI and QPIP for Canadian clubs. Default false. For a Canadian resident it also applies the CPP/QPP and EI credits and the enhanced CPP/QPP deduction on the Canadian return. With any take-home option set, the response adds net_pay (net = cash take-home, net_economic = net plus the 401(k) deferral), agent_fee, retirement_contribution, and payroll_taxes when payroll is on. amounts.total stays income tax only.",
+  "title": "Include Payroll Taxes"
+}

addedInput schema / properties / rca_contribution

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Salary deferred into a Retirement Compensation Arrangement by a Canadian club, in USD. Excluded from Canadian employment income until paid out: from worldwide income for a Canadian resident and in full from Canadian-source pay for a non-resident (Martin v. The King, 2024 TCC 153). US tax is unchanged. Not applied for US clubs. Comparisons count it after the estimated tax at payout (see rca_payout_tax_rate). Default 0.",
+  "title": "Rca Contribution"
+}

addedInput schema / properties / rca_payout_tax_rate

Added value: +{
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Estimated tax on the RCA when it is paid out, as a percent (0-100). Default models a player who retires to a no-tax US state and draws the RCA and its refundable tax account down at once: the US-duty-day share, already taxed by the US when contributed, bears Canada's 25% non-resident withholding, and the rest bears the US federal marginal rate on it (37% for a high earner). For a US person, who pays US tax on the whole contribution now, the default is the 25% withholding alone. Lowers net_pay.net_economic, which comparisons match on.",
+  "title": "Rca Payout Tax Rate"
+}

addedInput schema / properties / retirement_catch_up

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "none (default), 50_plus (+$8,000) or 60_to_63 (+$11,250). Catch-up contributions are always Roth for athletes (prior-year FICA wages over $150,000).",
+  "title": "Retirement Catch Up"
+}

addedInput schema / properties / retirement_contribution

Added value: +{
+  "anyOf": [
+    {
+      "type": "integer"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "Annual retirement contribution in USD. On a US club it is a 401(k) elective deferral capped at the 2026 limit ($24,500 plus catch-up). On a Canadian club it is an RRSP contribution capped at C$33,810, deducted from Canadian taxable income only. Default 0.",
+  "title": "Retirement Contribution"
+}

addedInput schema / properties / retirement_contribution_type

Added value: +{
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "null"
+    }
+  ],
+  "default": null,
+  "description": "401(k) only: pretax (default) lowers income-tax wages except in Pennsylvania, Philadelphia, Pittsburgh, Ohio cities, Kansas City and St. Louis; roth lowers nothing. RRSP contributions are always deductible.",
+  "title": "Retirement Contribution Type"
+}

First observedOct 22, 2026

TDQS

A4.4/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations declare non-read-only, non-destructive, closed-world, so the safety profile is largely settled; the description adds real value beyond that with defaults (exempt_signing_bonus_from_jock_tax true for a split, performance bonus only via its flag), the income-tax-only scope of results, and the framing that output is a calculation, not tax advice. The gaps are mostly on the margins – no note about rate limits, cost, or processing latency – but the substantive defaults and result semantics are covered.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The purpose is front-loaded, but the argument resolves into one long dense paragraph rather than separated blocks (input shape, defaults, take-home mode). It holds together because sentences build in a logical order, though a few are packed enough to slow an agent skimming for one rule.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a 21-parameter, output-schema-bearing calculator the description covers the high-risk paths – the two salary forms, bonus gating, RCA and payroll take-home behavior, and the net_pay/net_economic comparison rule. A handful of secondary parameters (estimated_playoff_games, retirement_catch_up, birth_country, filing_status) are left entirely to their schema text, which is acceptable at 100% coverage but not fully exhaustive.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters5/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With schema coverage at 100%, the schema documents each field, but the description adds cross-parameter constraints it cannot express: never send salary alongside base_salary or a bonus, performance_bonus counts only when include_performance_bonus_in_jock_tax is true, and how art_xvi4_inducement_sb interacts with an exempt signing bonus from a Canadian club. These are exactly the interactions most likely to be invoked wrongly.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The opening sentence names a specific verb (Calculate), a specific resource (professional-athlete tax), and a scope (one MLB season, Jock Taxes engine), which separates it cleanly from the NBA/NFL/NHL siblings. An agent knows exactly what this tool produces without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives explicit routing rules: call list_tax_calculator_inputs for allowed values, match players with list_team_players only after league/team/season_id are known, ask the user for a missing team or salary rather than inventing one. It also states the two mutually exclusive input shapes (salary alone vs base_salary plus bonuses) and when to escalate to take-home mode.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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