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

With no annotations, the description carries the full burden and does well: it discloses the result-set size (45), that ordering is editorial, and that positions are not standings — genuinely useful behavioral context an agent would otherwise get wrong. It does not describe the returned fields beyond 'the method they are known for', which is the main remaining gap.

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?

Roughly four sentences, front-loaded with what the tool returns before the filtering rules and the ordering caveat. It is dense and slightly run-on, but each sentence carries distinct information with no filler.

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?

For a 3-parameter, zero-required, annotation-free lookup tool with no output schema, it covers size, filtering, tag spelling, and ordering caveats — enough to call it correctly. It stops short of describing the shape of each returned record, which matters since no output schema exists.

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 3 is the baseline, but the description adds real meaning: exact lower-case tag spellings with a concrete counterexample ('9-ball' and 'Nine-ball' will miss), single-tag limitation, and that country is matched as commonly listed. q is only restated as 'part of a name', so it adds less there.

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 states a specific resource (45 pool/snooker/carom players, each with the method they're known for) with an explicit count, so an agent knows exactly what it retrieves. It never differentiates itself from the sibling pool_search, which is the most likely source of confusion, so it stops short of a 5.

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?

Clear operational guidance: filter by name fragment, country, or exactly ONE game tag, combine them, or send nothing for the full 45. It also adds a strong usage constraint — 'the order is editorial and is NOT a ranking; do not present a position as a standing'. It gives no guidance on when to prefer this over pool_search, so no exclusion criteria.

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