irs-taxpayer-mcp

Overview Schema Source Related Servers Discussions Admin

calculate_total_tax

Read-onlyIdempotent

Calculate combined federal and state tax liability with a single call, returning federal breakdown, state tax, and combined totals for complete tax planning.

Instructions

Calculate combined federal + state tax for a complete picture of total tax liability. Returns federal breakdown, state tax, and combined totals in one call.

Input Schema

TableJSON Schema

Name	Required	Description
`taxYear`	Yes	Tax year (2024, 2025, or 2026)
`w2Income`	No	W-2 wage income
`stateCode`	Yes	Two-letter state code (e.g., 'CA', 'TX', 'NY')
`dependents`	No	Legacy dependent count for nonrefundable CTC only
`grossIncome`	Yes	Total gross income including supplied capital gains, qualified dividends, Social Security benefits, and gross retirement distributions
`hasForm2555`	No
`capitalGains`	No	Long-term capital gains
`earnedIncome`	No	Schedule 8812 earned income for ACTC
`filingStatus`	Yes	Filing status
`taxExemptInterest`	No
`earnedIncomeCredit`	No	EITC used by 3-or-more-child ACTC method
`itemizedDeductions`	No	Total itemized deductions
`qualifiedDividends`	No	Qualified dividends included in gross income
`netInvestmentIncome`	No	Total net investment income used for NIIT
`capitalGainsLongTerm`	No	Whether capital gains are long-term (default: true)
`selfEmploymentIncome`	No	Self-employment income
`aotcRefundableAllowed`	No
`otherDependentsForOdc`	No	Verified dependents for ODC
`shortTermCapitalGains`	No	Short-term capital gain or loss
`aboveTheLineDeductions`	No	Above-the-line deductions
`socialSecurityBenefits`	No
`qualifiedBusinessIncome`	No	QBI for Section 199A deduction
`qualifiedBusinessIsSstb`	No
`retirementDistributions`	No
`socialSecurityTaxesPaid`	No	Payroll-tax amount for 3-or-more-child ACTC method
`qualifiedBusinessW2Wages`	No
`qualifyingChildrenForCtc`	No	Verified CTC/ACTC qualifying children
`aotcStudentQualifiedExpenses`	No
`longTermCapitalLossCarryover`	No	Prior-year long-term capital loss carryover
`shortTermCapitalLossCarryover`	No	Prior-year short-term capital loss carryover
`qualifiedBusinessPropertyBasis`	No
`taxableRetirementDistributions`	No
`lifetimeLearningQualifiedExpenses`	No
`marriedFilingSeparatelyLivedWithSpouse`	No
`earlyRetirementDistributionSubjectToPenalty`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`text`	Yes
`error`	No
`isError`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed27 schema fields changedv1.0.1Sep 7, 2026

addedInput schema / properties / aotcRefundableAllowed
```
Added value: +{
+  "type": "boolean"
+}
```

addedInput schema / properties / aotcStudentQualifiedExpenses

Added value: +{
+  "items": {
+    "minimum": 0,
+    "type": "number"
+  },
+  "type": "array"
+}

changedInput schema / properties / dependents / description

Previous value: -"Number of qualifying child dependents"New value: +"Legacy dependent count for nonrefundable CTC only"

addedInput schema / properties / earlyRetirementDistributionSubjectToPenalty
```
Added value: +{
+  "minimum": 0,
+  "type": "number"
+}
```

addedInput schema / properties / earnedIncome

Added value: +{
+  "description": "Schedule 8812 earned income for ACTC",
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / earnedIncomeCredit

Added value: +{
+  "description": "EITC used by 3-or-more-child ACTC method",
+  "minimum": 0,
+  "type": "number"
+}

changedInput schema / properties / grossIncome / description

Previous value: -"Total gross income in USD"New value: +"Total gross income including supplied capital gains, qualified dividends, Social Security benefits, and gross retirement distributions"

addedInput schema / properties / hasForm2555
```
Added value: +{
+  "type": "boolean"
+}
```
addedInput schema / properties / lifetimeLearningQualifiedExpenses
```
Added value: +{
+  "minimum": 0,
+  "type": "number"
+}
```

addedInput schema / properties / longTermCapitalLossCarryover

Added value: +{
+  "description": "Prior-year long-term capital loss carryover",
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / marriedFilingSeparatelyLivedWithSpouse
```
Added value: +{
+  "type": "boolean"
+}
```

addedInput schema / properties / netInvestmentIncome

Added value: +{
+  "description": "Total net investment income used for NIIT",
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / otherDependentsForOdc

Added value: +{
+  "description": "Verified dependents for ODC",
+  "minimum": 0,
+  "type": "integer"
+}

addedInput schema / properties / qualifiedBusinessIsSstb
```
Added value: +{
+  "type": "boolean"
+}
```
addedInput schema / properties / qualifiedBusinessPropertyBasis
```
Added value: +{
+  "minimum": 0,
+  "type": "number"
+}
```

addedInput schema / properties / qualifiedBusinessW2Wages

Added value: +{
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / qualifiedDividends

Added value: +{
+  "description": "Qualified dividends included in gross income",
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / qualifyingChildrenForCtc

Added value: +{
+  "description": "Verified CTC/ACTC qualifying children",
+  "minimum": 0,
+  "type": "integer"
+}

addedInput schema / properties / retirementDistributions

Added value: +{
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / shortTermCapitalGains

Added value: +{
+  "description": "Short-term capital gain or loss",
+  "type": "number"
+}

addedInput schema / properties / shortTermCapitalLossCarryover

Added value: +{
+  "description": "Prior-year short-term capital loss carryover",
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / socialSecurityBenefits

Added value: +{
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / socialSecurityTaxesPaid

Added value: +{
+  "description": "Payroll-tax amount for 3-or-more-child ACTC method",
+  "minimum": 0,
+  "type": "number"
+}

addedInput schema / properties / taxExemptInterest

Added value: +{
+  "minimum": 0,
+  "type": "number"
+}

changedInput schema / properties / taxYear / description

Previous value: -"Tax year (2024 or 2025)"New value: +"Tax year (2024, 2025, or 2026)"

addedInput schema / properties / taxableRetirementDistributions
```
Added value: +{
+  "minimum": 0,
+  "type": "number"
+}
```

changedOutput schema / (root)

Previous value: -nullNew value: +{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "additionalProperties": false,
+  "properties": {
+    "error": {
+      "additionalProperties": false,
+      "properties": {
+        "code": {
+          "type": "string"
+        },
+        "message": {
+          "type": "string"
+        },
+        "suggestion": {
+          "type": "string"
+        }
+      },
+      "required": [
+        "code",
+        "message",
+        "suggestion"
+      ],
+      "type": "object"
+    },
+    "isError": {
+      "type": "boolean"
+    },
+    "text": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "text",
+    "isError"
+  ],
+  "type": "object"
+}

First observedv0.5.3Feb 25, 2026

TDQS

A4/5.0

Behavior4/5

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

Annotations already cover read-only, idempotent, and non-destructive behavior, so the description's burden is lower. The description adds useful behavioral context by disclosing the result composition (federal breakdown, state tax, combined totals) and the one-call efficiency, which is not visible from the annotations alone.

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

Conciseness5/5

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

The description is a single front-loaded sentence followed by a clear return-value sentence. Every word earns its place, and there is zero redundancy or filler.

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

Completeness3/5

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

Given the tool's complexity (35 parameters, many optional credits and deduction inputs), the description is minimally adequate but doesn't help the agent know which optional inputs matter for a given scenario. The output schema and property descriptions compensate partially, but the high parameter count creates a completeness gap.

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

Parameters2/5

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

The description provides no parameter-level guidance despite a large 35-parameter schema with 63% description coverage. It doesn't clarify how optional fields like capitalGains, itemizedDeductions, or earnedIncomeCredit feed into the combined calculation, leaving the agent to infer meaning from the schema alone.

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 description states a specific verb ('calculate') and resource ('combined federal + state tax'), and explicitly lists what the call returns: federal breakdown, state tax, and combined totals. This clearly differentiates it from siblings like calculate_federal_tax and estimate_state_tax, which cover only one jurisdiction.

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

Usage Guidelines4/5

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

The phrase 'complete picture of total tax liability' and 'in one call' implies this is the right tool when both federal and state results are needed together. It doesn't explicitly name alternatives like calculate_federal_tax or estimate_state_tax, but the context makes the intended use clear without excluding them.

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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