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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds a genuinely useful data-quality trait: the number field is empty for sets PSA lists without one (e.g. many autograph/player-only sets), warning the agent not to treat missing numbers as an error. It stops short of describing pagination or ordering.

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 compact sentences with the resource and its scope front-loaded, followed by the useful edge-case caveat. 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?

An output schema exists, so return values need no explanation, and annotations cover safety. The description covers the resource, the source of the id, and the empty-number caveat, leaving only ordering/pagination unstated, which is a minor gap for a single-set checklist.

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% and the SetID property already documents itself as the numeric set id from a psa-cardfacts-sets result. The description largely restates this, adding only the chaining emphasis. Baseline 3 is correct when the schema carries the parameter meaning.

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+resource: it returns one CardFacts set's full card checklist, including each card's name and printed number. It also names the sibling psa_cardfacts_sets as the origin of the id, so the agent can distinguish it from the sets-listing tool.

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 establishes the chaining context ('set_id is the numeric id from a psa_cardfacts_sets result'), which tells the agent this is a follow-up call after listing sets. It does not explicitly state when not to use it or name a competing alternative, but for a leaf-detail tool that is minor.

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