chesscom_titled_players

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

Annotations already mark it as read-only, open-world, and idempotent, and the description adds important behavioral details: output shape (flat list of username strings, not objects), auth requirements ('Auth: none needed'), and the intended chaining to chesscom_player. No contradictions with annotations.

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 extremely compact: one-line purpose, return type, example, and auth. Every sentence adds value and the core purpose is front-loaded, making it easy for an agent to parse quickly.

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 read-only tool with no output schema, the description covers the purpose, output format, example invocation, and auth. It even points to chesscom_player for detail, making it self-contained 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 schema covers the single parameter fully with an enum and description (100% coverage), so the baseline is 3. The description adds a concrete example ({"title": "GM"}) and clarifies that the output is usernames only, but does not provide additional parameter semantics beyond what the schema already states.

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 opens with a specific verb+resource: 'Every player holding a given FIDE title — usernames only.' It clearly distinguishes from sibling tools like chesscom_player (single player details) and leaderboards, and explicitly states the output is a flat list of username strings. The scope is unambiguous.

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 gives clear context by showing an example ({"title": "GM"}) and noting that results should be 'feed one to chesscom_player for detail', suggesting a downstream workflow. It does not explicitly list alternative tools or exclusion scenarios, but the purpose and intended usage are sufficiently clear for correct selection.

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