list_agencies

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds important behavioral details: the effect of the summary_only parameter (strips children and cfr_references) and the resulting response sizes (~20 KB vs ~100 KB). No contradictions.

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 four sentences, each serving a purpose: purpose, return values, use case, and parameter behavior. No unnecessary words or repetition. Information is front-loaded.

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?

The tool is simple with one optional parameter and has an output schema. The description covers the action, return data, parameter usage, and response size, making it fully complete for an agent to use 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?

The input schema has one boolean parameter with 0% description coverage. The description thoroughly explains summary_only: default true, what it strips (children and most cfr_references), response size difference, and how to get full payload. This fully compensates for the schema's lack of parameter descriptions.

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 'List all agencies with their CFR title and chapter references' and specifies the returned data (names, slugs, titles/chapters). It is distinct from sibling tools like search_cfr or get_cfr_structure, which focus on content or structure, not agency listing.

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 provides a specific use case: 'Useful for finding which chapter corresponds to an agency's FAR supplement.' It implicitly guides when to use this tool, though it does not explicitly exclude alternatives or mention when not to use it.

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