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

With no annotations, the description carries full burden. It states the tool is a read operation (listing legislators) and mentions the return includes people_id. It doesn't disclose pagination or full response structure, but for a simple list tool this is adequate and adds context on the source of session_id.

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, front-loads the core function, and then provides usage guidance with the alternative tool and parameter source. There is no redundant information and the structure is clear.

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 tool with a single parameter, no output schema, and no annotations, the description covers purpose, usage, and parameter source. It doesn't detail the response fields beyond people_id, but that is acceptable given the tool's simplicity; the guidance is sufficient for an agent to invoke it 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?

Schema coverage is 100% as the only parameter, session_id, already has a description ('session_id from list_sessions (filter by state)'). The description reinforces this by saying 'Get session_id from list_sessions.' It adds no new semantic detail beyond the schema, meeting the baseline for full coverage.

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 every legislator who served in a specific session, and distinguishes it from list_legislators which handles the current roster by state. It also notes the inclusion of people_id, making the resource and output explicit.

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 explicitly tells when to use this tool (for a past or special session) versus list_legislators (current roster by state), and instructs the agent to get session_id from list_sessions. This is clear and actionable guidance.

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