Federal Register

list_agencies

Read-only

List agencies with their IDs, names, slugs, and parent agencies.

Use the 'slug' values with search_documents() and other tools.
Common procurement slugs:
- defense-department (DoD)
- general-services-administration (GSA)
- national-aeronautics-and-space-administration (NASA)
- defense-acquisition-regulations-system (DARS/DFARS)
- federal-procurement-policy-office (OFPP and the CAS Board)
- small-business-administration (SBA)
- veterans-affairs-department (VA)

The FAR has no single slug. FAR rules and notices are filed jointly
under DoD, GSA and NASA; OFPP was added only from about mid-2025, so
the OFPP slug misses earlier FAR rules. The agency named 'Federal
Acquisition Regulation System' (federal-acquisition-regulation-system)
holds 2 documents ever; it carries a note in these results. For FAR
documents use search_documents(far_council=True) or
open_comment_periods(far_council=True).

Parameters:
- query: optional case-insensitive substring match against name, short_name,
  and slug. Recommended: narrow results before pulling full detail.
- include_detail: if False (default), returns only id/name/short_name/slug/parent_id.
  If True, returns all fields (description, urls, etc.). The full dump is ~700KB.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`query`	No
`include_detail`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedOct 21, 2026

TDQS

A4.9/5.0

Behavior5/5

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

Beyond the read-only hint in annotations, the description provides critical behavioral details, such as the operational impact of `include_detail=True` ('The full dump is ~700KB') and essential data caveats (FAR slug issues, OFPP timeline).

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 description is detailed, which is necessary given the complexity and zero schema coverage. While lengthy, the information provided is highly valuable and non-redundant, justifying its size.

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?

The definition is exceptionally complete. It covers what the tool does, how to filter it, the operational costs (data dump size), and provides crucial domain knowledge (slug limitations) that ensures the agent makes an informed decision.

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?

Since schema coverage is 0%, the description must provide all meaning. It clearly explains the function, case-insensitivity, and recommendation for the 'query' parameter, and thoroughly details the data scope and size implications of 'include_detail'.

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 tool's function: 'List agencies with their IDs, names, slugs, and parent agencies.' It clearly distinguishes itself from siblings by being an entity listing tool, not a document search tool.

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 provides explicit guidelines on when to use the returned data, stating, 'Use the 'slug' values with search_documents() and other tools.' Furthermore, it tells the agent when to use specific siblings for FAR-related tasks.

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

All Federal Register tools Inspect

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