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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety needs no restating. The description still adds behavior the annotations cannot: it discloses what comes back (teams plus next fixture) and warns that omitting qualifier words changes the result set ('dropping them answers a different question'). It does not cover result ordering or what an empty result means, keeping it short of a 5.

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?

Three sentences, front-loaded with what is returned, then when to call, then the parameter trap. The final sentence is long but each clause carries a distinct instruction; little waste.

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 responsibly sketches the return ('the teams ... and which of them plays next'), and the annotations cover the safety profile for this read-only, idempotent tool. Missing only pagination/ordering behavior, which is minor for a per-club list.

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 coverage is 100%, so a 3 is the floor; the description earns more by explaining the consequence of the qualifier parameter ('dropping them answers a different question'), which turns a formatting instruction into a decision rule. It does not explain the `asked` parameter's purpose, but the schema already does that verbatim.

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 and resource ('Returns the teams a named club fields this year') plus the added payload ('which of them plays next'). It also explicitly separates the tool from the sibling query_club by scope (whole club vs. club page/performance), so an agent can pick correctly without opening the 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?

States the trigger condition ('whenever someone asks about a whole club by name'), the ordering ('before you narrow the question to a single team'), and names the alternative with the condition that selects it ('For how the club is doing, call query_club'). This is exactly the when/when-not/alternative pattern.

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