irs-taxpayer-mcp

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calculate_obbb_deductions

Read-onlyIdempotent

Calculate your 2025+ OBBB deductions for tip income, overtime pay, senior bonus, and auto loan interest. See which deductions you qualify for and total tax savings.

Instructions

Calculate all OBBB (One Big Beautiful Bill) new deductions for TY2025+: tips income deduction, overtime pay deduction, senior bonus deduction, and auto loan interest deduction. Shows which deductions you qualify for and the total tax savings.

Input Schema

TableJSON Schema

Name	Required	Description
`age`	No	Taxpayer age (needed for senior bonus)
`agi`	Yes	Adjusted Gross Income
`taxYear`	Yes	Tax year (2025+)
`spouseAge`	No	Spouse age if MFJ
`tipIncome`	No	Annual tip income from qualifying occupation
`overtimePay`	No	Annual overtime premium pay
`filingStatus`	Yes
`marginalRate`	No	Your marginal tax rate (for savings estimate, e.g. 0.22)
`autoLoanInterest`	No	Interest paid on qualifying US-assembled new vehicle loan

Output Schema

TableJSON Schema

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

Schema Changelog

Changes observed during successful MCP inspections.

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

A4.2/5.0

Behavior4/5

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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds behavioral value beyond the annotations by stating that it determines qualification and reports total tax savings, which clarifies the computed output without contradicting the read-only nature.

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 exactly two sentences, front-loading the action and resource, and then listing the deductions and the output. Every sentence earns its place with no redundancy or filler.

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?

Given the 9-parameter schema, output schema, and read-only annotations, the description is sufficiently complete: it names all deductions, scopes the tax years, and states the output. It could add a bit more about eligibility conditions or calculation assumptions, but the structured data covers much of that context.

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 89%, so the schema already documents most parameters such as age, AGI, tipIncome, and autoLoanInterest. The description names the four deduction categories, which helps map them to parameters, but it does not add new semantic details beyond what the schema provides.

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 uses a specific verb ('Calculate') and a precise resource ('all OBBB new deductions for TY2025+'), enumerating the four deduction types and the expected output. This clearly differentiates the tool from general tax calculators and list_deductions by naming its exact scope.

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 description clearly frames the tool for the OBBB new deductions in TY2025+, and the output statement ('Shows which deductions you qualify for') makes the use case apparent. It does not explicitly name alternative sibling tools or state when not to use them, but the context is strong enough for an agent to select it appropriately.

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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