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

Annotations already cover the safety profile (readOnlyHint/openWorldHint), and the description adds real context: results are grouped/ordered by team, the stats arrive as a numeric map, with multikill counts plus team and opponent attached. It adds useful shape information without stating anything that contradicts 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?

Front-loaded with the return payload, then the required input source, then the sibling escape hatch. The enumeration of stat categories is long but justified since it previews available metrics; slightly dense for a single sentence.

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?

A single-match lookup with one required, fully documented parameter, an existing output schema, and read-only annotations — the description covers purpose, input provenance, scope, and the alternative. Nothing an agent needs to invoke it correctly is missing.

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?

Only one parameter and schema coverage is 100%, including a concrete slug example, so the schema already carries the semantics. The description's 'Provide slug from bo3_match_history' adds provenance but nothing beyond what the schema description says — 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?

States a specific verb and resource ('Returns every player's statistics for one BO3.gg match'), then enumerates the stat families returned and the ordering (by team). It explicitly separates itself from bo3_player_stats, so an agent can pick it without opening sibling schemas.

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?

Gives the positive use case ('see who performed in a match'), the named alternative for a different need ('bo3_player_stats for a player's totals over a period'), and even routes the agent to bo3_match_history for obtaining the slug. Both when-to-use and where-to-get-input are explicit.

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