apitennis_h2h

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

The description significantly extends beyond the annotations. It discloses that the return shape is from vendor docs and unverified, warns to treat it as approximate, highlights that `result` is an object rather than a list like other methods, and specifies the authentication requirement. These are valuable behavioral traits not covered by readOnlyHint, openWorldHint, or idempotentHint.

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 well-structured with a clear opening sentence, return shape, caveat, example, and auth note. It is slightly verbose due to the vendor-doc warning, but every sentence serves a purpose. The important caveats are prominently placed, and the overall length is acceptable for the amount of critical information.

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?

Given the lack of an output schema, the description provides a rough return structure with caveats about its accuracy, which is essential. It also includes an example and auth requirements. However, it does not cover error cases, pagination, or data freshness beyond the unverified note, which would make it more complete. For a relatively simple tool, it is fairly thorough.

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 already provides 100% parameter coverage with descriptions for method, first_player_key, and second_player_key. The description adds an example with concrete key values and notes the default method, but does not significantly deepen understanding beyond the schema. Thus the baseline score of 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 explicitly states 'Head-to-head history between two players, plus each one's recent form,' which is a specific verb+resource combination. It clearly distinguishes itself from sibling tools like apitennis_events, apitennis_fixtures, etc., by specifying the H2H nature and the inclusion of recent form.

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 implies the use case (H2H history) but does not explicitly state when to use this tool vs alternatives. It provides an example but no direct comparison or exclusion of other tennis tools. The purpose clarity partially compensates, but explicit guidance on when to choose this over siblings is missing.

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