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

Annotations already declare readOnly, idempotent, and non-destructive behavior, so the bar is lower. The description adds value by revealing the return fields and the caveat 'where curated', implying some fields may be missing for certain tournaments. This extra context about data completeness goes beyond the 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 one tight sentence with an em-dash pivot, front-loading the key purpose ('One tournament by its stable id') and adding terse, relevant details about id source and fields. No filler or redundancy.

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 single-parameter read tool with a detailed output schema, robust annotations (readOnly, idempotent, openWorld), and a well-documented parameter, the description is fully adequate. It covers id source, return fields, and the 'where curated' caveat, making it complete for the tool's context.

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% for the single parameter, and the schema already states tournament_id is 'Stable tournament id, as returned by search_tournaments or carried on a match as tournament_id'. The description reinforces 'stable' and 'carried on match objects', but adds little beyond the schema, so baseline 3 is appropriate.

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 clearly states 'One tournament by its stable id', specifying the resource (tournament) and retrieval verb implied by 'get'. It distinguishes from sibling search_tournaments by emphasizing the stable id and its source on match objects, and enumerates returned fields (name, tour, surface, indoor, etc.).

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 implicitly tells when to use this tool: when you already have a stable tournament_id, especially from match objects or search_tournaments. However, it does not explicitly exclude alternatives or state when not to use it, leaving some inference to the agent.

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