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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=true, so safety and the external-data nature are covered. The description adds value by enumerating the returned fields, which matters since no output schema exists. It does not disclose however what happens on ambiguous surname matches or whether results are cached/rate-limited.

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?

One sentence, front-loaded with the verb and resource, listing outputs and inputs in a natural order. Nothing is redundant or padded.

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 one-parameter lookup tool with annotations covering the safety profile, the description is nearly complete: it names the source, the retrievable fields, and the two key formats. The only meaningful gap is ambiguity handling when a surname matches multiple players.

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% and the single query parameter is fully documented there, including the 'Surname, First name' and FIDE ID forms. The description restates the same key options without adding format or matching-behavior detail, 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?

States a specific verb (look up) and a specific resource (official FIDE ratings), and enumerates the data returned — standard/rapid/blitz ratings, title, federation, birth year — plus the two lookup keys. That is enough to tell it apart from siblings like elo_change or chess_profile, though it never names an alternative explicitly.

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 agent can infer it should call this when it has a player name or FIDE ID and needs official rating data. There is no statement of when to prefer it over elo_change or chess_profile, and no note on prerequisites or failure cases.

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