Arc & Ledger Tax Reference

Decode an IRS notice

decode_irs_notice

Read-only

Use when a user provides the code from an IRS notice or letter and wants a general explanation, the usual response window, or the next procedural step. Do not request the notice itself or any taxpayer identifier.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "notice_code": "<notice_code>"
    },
    "name": "decode_irs_notice"
  }
}

Input Schema

Name	Required	Description
`brief`	No	Set true for a shorter answer: skips the generic how-to-read guidance and common-error list.
`notice_code`	Yes	The notice or letter code printed on the IRS mail, e.g. "CP2000", "CP 14", "LT11", "Letter 1058".
`amount_shown`	No	The dollar amount the notice proposes or bills, if any. Optional; used only for context, never stored.
`received_date`	No	Date on the notice (YYYY-MM-DD). Used to compute the response deadline. The IRS clock runs from the notice date printed on the letter.

Output Schema

Name	Required	Description
`relay`	Yes	Instruction to the calling assistant: relay figures and dates verbatim (identical on every response).
`next_step`	Yes	A single review link appropriate to this server surface.
`disclaimer`	Yes	General-information disclaimer (identical on every response).
`source_url`	Yes	Official IRS or FinCEN authority to review before relying on the result.
`server_version`	No	Server release that produced this response (matches GET /version).

Schema Changelog

Changes observed during successful MCP inspections.

First observedJul 28, 2026

TDQS

A4.5/5.0

Behavior4/5

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

Annotations already declare readOnlyHint=true, so the safe reading behavior is clear. The description adds that the tool does not request taxpayer identifiers or the notice itself, which is useful behavioral context. No contradictions with annotations.

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?

Two sentences with zero waste. The first sentence gives the core purpose and when to use, the second adds a critical constraint. Perfectly front-loaded and efficient.

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

Completeness5/5

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

Given the presence of an output schema and 100% parameter coverage, the description sufficiently covers all necessary aspects: purpose, usage context, parameter hints, and constraints. No gaps identified.

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 coverage is 100%, so all four parameters are documented in the input schema. The description adds no further semantic value beyond the schema, meeting the baseline expectation adequately.

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 clearly states the verb 'decode' and the resource 'IRS notice', specifying that it provides explanations, response windows, or procedural steps. It distinguishes from sibling tools like check_obligations or estimate tools by focusing on decoding notice codes.

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?

Explicitly states when to use: when a user provides an IRS notice code for explanation or next steps. Also includes a clear negative instruction: 'Do not request the notice itself or any taxpayer identifier.' This provides comprehensive guidance on appropriate usage.

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

All Arc & Ledger Tax Reference tools Inspect

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