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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds value beyond that: it discloses result ordering (most recent first), the returned fields (handicap and number of shared rounds), and the membership rule that excludes friends.

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, front-loaded with what the tool returns, then the follow-up action. Every clause carries information (scope, ordering, fields, exclusion, next step); no repetition of the title or annotations.

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?

With no output schema, the description carries the burden of describing returns and does so (handicap, times played together, recency ordering). For a zero-parameter read tool that is essentially complete; only the absence of a volume limit or named alternative tool leaves a small gap.

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 tool takes zero parameters, which is the baseline-4 case; there is nothing for the description to disambiguate. It correctly does not waste words inventing parameter guidance.

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?

Names a specific verb+resource (list the player's regular partners, «Tus habituales») and defines the set precisely: companions who are not Badgie friends, federated by licence or invited by name. It also states the ordering and the fields returned, so the agent can distinguish it from the friends-listing sibling 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?

Gives a concrete next step ('Para meterlos en una partida: add_party_player con su licencia o su nombre') and an explicit exclusion ('Los amigos de Badgie no salen aquí'), which steers the agent toward the friends tool for that case. The exclusion is stated but the alternative tool is not named, so it stops short of fully explicit routing.

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