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

Annotations already declare this a safe read (readOnlyHint=true, destructiveHint=false, openWorldHint=true), so the description only needs to add context — and it does, by explaining that FEC and Bioguide ids are conditionally present and that people_id signals an available voting record. It stops short of describing not-found or invalid-id behavior, which is the remaining gap.

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?

Front-loaded with the verb, resource, and endpoint, then layers conditional data semantics and follow-on routing. Dense and mostly waste-free, though the REST path restates what the name already conveys.

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?

With no output schema, the description usefully enumerates returned fields and conditional ids, and covers id sourcing plus next-step tools. Only error/empty-result behavior is unaddressed, a minor gap for a single-param read tool.

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% and the single id parameter is fully documented, so the schema carries the load. The description adds the provenance hint (id comes from list_candidates) but omits get_midterms, which the schema does list, so it adds no meaning beyond the schema.

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?

States a specific verb and resource ('Fetch one election candidate by id'), names the backing endpoint, and enumerates exactly what is returned (party, office, district, cycle, FEC filer id, Bioguide id). It is clearly distinguishable from sibling list_candidates and get_candidate_photo.

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?

Gives explicit entry and exit routing: get the id from list_candidates, and if people_id is set, pass it to get_legislator or get_legislator_scorecard. Both the precondition and the follow-on alternatives are named.

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