irs-taxpayer-mcp

Overview Schema Source Related Servers Discussions Admin

check_credit_eligibility

Read-onlyIdempotent

Determine which federal tax credits you may qualify for based on your adjusted gross income, filing status, and personal or financial circumstances.

Instructions

Check which tax credits you may be eligible for based on your situation.

Input Schema

Name	Required	Description
`agi`	Yes	Adjusted Gross Income
`taxYear`	No	Tax year (default: 2026)
`boughtEV`	No	Purchased an electric vehicle this year
`isStudent`	No	Currently enrolled in post-secondary education
`hasChildren`	No	Have qualifying children under 17
`numChildren`	No
`filingStatus`	Yes
`hasChildcare`	No	Pay for childcare to work
`installedSolar`	No	Installed solar panels or renewable energy
`paidForeignTax`	No	Paid income tax to a foreign country
`hasEarnedIncome`	No	Has earned income from work
`hasStudentLoans`	No	Paying student loan interest
`madeHomeImprovements`	No	Made energy-efficient home improvements
`hasMarketplaceInsurance`	No	Bought health insurance through ACA marketplace
`hasRetirementContributions`	No	Contributed to IRA/401k

Output Schema

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

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedv1.2.4Nov 4, 2026
- removedInput schema / additionalProperties
```
Removed value: -false
```
- addedInput schema / properties / numChildren / maximum
```
Added value: +9007199254740991
```
- addedInput schema / properties / taxYear
```
Added value: +{
+  "description": "Tax year (default: 2026)",
+  "type": "number"
+}
```

Changed1 schema field changedv1.0.1Sep 7, 2026

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

B3.4/5.0

Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered structurally. The description adds nothing beyond that — it doesn't say results are estimates rather than determinations, whether omitted optional inputs degrade accuracy, or how partial data is handled.

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?

A single, front-loaded sentence with no filler or restated name. Nothing in it is wasted.

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?

With an output schema present, the description needn't explain return values, and the schema documents nearly every field. For a 15-parameter tool the only real gap is not flagging which optional flags materially change results — a minor omission given the structured coverage.

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

Parameters3/5

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

Schema description coverage is 87% with only two required fields, so the schema itself carries nearly all parameter meaning. The description adds no parameter-level context, such as that agi/filingStatus are mandatory while the boolean flags drive which credits are surfaced.

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

Purpose4/5

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

States a specific verb and resource ('Check which tax credits you may be eligible for') plus the basis for the check ('based on your situation'). It is clearly distinguishable from siblings like list_tax_credits or calculate_eitc in intent, though it never names those siblings explicitly.

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

Usage Guidelines2/5

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

There is no guidance on when to prefer this over the many closely related siblings (list_tax_credits, calculate_eitc, estimate_premium_tax_credit, analyze_education_tax_benefits), no prerequisites, and no statement of what the agent must supply to get meaningful results. Usage is only implied by the phrase 'based on your situation'.

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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