fr_agencies

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

Annotations already provide readOnlyHint=true, so the safety profile is known. The description adds value by specifying the return fields and noting the database size ('470+ agencies'), which sets expectations. It does not mention pagination or rate limits, but for a simple list endpoint this is adequate.

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

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

The description is two sentences, tightly written, and front-loaded with the main action. Every sentence earns its place: purpose, return fields, and scale. No redundant or vague wording.

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

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

For a no-parameter, list-style tool with no output schema, the description is complete: it states what the tool returns and the intended use of slugs for filtering. This is sufficient for an agent to select and invoke the tool correctly.

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

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

There are zero parameters, and the schema coverage is effectively 100% (no properties). The description adds no parameter information, but with no parameters this is a baseline 4; there is nothing more to explain.

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

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

The description clearly states it lists federal agencies that publish in the Federal Register, with a specific verb ('List') and resource ('federal agencies'). It also identifies the return fields (names, short names, slugs, URLs) and scale (470+ agencies), distinguishing it from other FR tools that search rules or documents.

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

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

The description implies usage through 'slugs (for filtering)', suggesting this tool is used to obtain slugs for filtering other Federal Register endpoints. However, it lacks explicit when-to-use versus alternatives or exclusions, but the context is clear enough for a no-parameter list tool.

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