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

Annotations already cover the safety profile (readOnly, idempotent, openWorld, non-destructive), so the description focuses on data provenance instead. It discloses that primary vote counts come from Wikipedia, are non-official, are labelled as such, and cite state election authorities, while money and incumbency data come from the FEC. It also states the error behavior for nonexistent districts. This is useful context beyond the annotations, though it does not discuss freshness or rate limits.

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 a single dense sentence that front-loads the resource scope ('One US House district or Senate seat') before listing what is included. Every clause carries information, though the sentence is long and could be broken into shorter statements for readability. There is no filler.

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 an output schema present, the description need not explain return values, and with annotations covering safety, it does not need to repeat that. What it must convey—the data sources, the unofficial status of primary vote counts, the FEC provenance of money and incumbency data, and the error behavior for invalid districts—is all present. An agent has enough to call the tool correctly and interpret the results with appropriate caveats.

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 description coverage is 100%, so all five parameters are already documented in the schema, and the description adds little parameter-level detail. It clarifies that the tool operates on one district or seat and that a nonexistent district produces an error naming valid districts, which slightly enhances the district parameter's semantics. But it does not explain the special or cycle parameters, so baseline 3 applies.

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 names a specific resource (one US House district or Senate seat) and enumerates what it returns: incumbent status, FEC-registered candidates by party, fundraising totals, primary winners, and election dates. An agent knows exactly what data this tool produces. However, it never mentions the sibling list_races, so the boundary between listing races and fetching a single matchup is left implicit.

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?

Usage is only implied: the description says it returns data for one district or seat, which suggests it is the drill-down tool for a single race. There is no explicit when-to-use guidance, no mention of list_races as the alternative for listing multiple races, and no statement about prerequisites or the relationship between the two tools.

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