get_head_to_head

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

No annotations are present, so the description carries full responsibility for behavioral disclosure. It goes well beyond the obvious by explaining that ratings are rounded, empty matches mean no prior meeting, unreadable scores appear as empty games with a raw score field, and there is no 'result' field as in get_player. This is rich, useful edge-case behavior.

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 purpose is front-loaded first, followed by output summary, then edge-case behavior. Every sentence earns its place, and the formatting separates concerns clearly without 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?

There is no output schema, so the description must explain return semantics; it does so thoroughly by listing wins, percentages, ratings, match list, and all important edge cases. For a two-parameter lookup tool, nothing essential is missing for an agent to call it 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?

Schema description coverage is 0%, so the description must compensate, but it only says 'two players' and does not define player_id/opponent_id formats, examples, or how the IDs map to the two sides of the match. The parameter names are self-explanatory, but the description adds no concrete input semantics beyond the schema's bare titles.

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 and resource: 'Возвращает очное противостояние двух игроков' (returns the head-to-head match of two players), then enumerates what is returned. It also explicitly distinguishes itself from the sibling tool get_player by pointing out the missing 'result' field and rounded ratings, so an agent can tell them apart.

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: use this tool for head-to-head statistics, and go to get_player for exact two-decimal ratings. It also explains the meaning of an empty 'matches' array, which helps decide whether players have actually met. It does not provide a broader when-to-use/when-not-to-use statement, but the guidance is sufficient for this tool.

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