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

Annotations already declare this is a non-read, non-destructive, non-idempotent, closed-world mutation, so the safety profile is covered. The description adds the useful timing constraint on when leaving is valid, but says nothing about consequences (e.g. losing queue position) or re-entry rules.

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?

Two short sentences with zero waste, with the core action and its timing constraint front-loaded ahead of the alternative-tool pointer.

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 simple no-param-output state-changing action whose annotations carry the safety profile, the description covers action, timing, and the alternative tool. Only edge details such as whether queue position is retained or re-joining is possible are left unstated.

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?

There is a single parameter (api_key) with 100% schema description coverage, including the note that Authorization: Bearer clients may omit it. The description adds no parameter meaning beyond the schema, so the 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 and resource ('Leave the lobby') and pairs it with a precise temporal scope ('before your match starts'). It also names the sibling it is not (wait_for_turn once the match has started), so an agent can distinguish it from wait_for_turn and join_queue without opening a schema.

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?

Explicitly states when to use it ('before your match starts') and when not to, redirecting to wait_for_turn once the match has begun. The alternative and the condition that selects it are both named, leaving nothing to inference.

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