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

Annotations already declare readOnly, idempotent, non-destructive, non-openWorld, so the safety profile is covered. The description adds real behavioral value beyond them: a hard result cap of 10 matches and the fact that results are ids intended as input to `fetch`, which shapes how the agent should chain calls.

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 sentences, no filler, and the front-loaded clause pairs the action with the supported franchises. The follow-up-tool hint is placed last, which is the right ordering for an agent that reads the first sentence to route.

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-value detail is rightly omitted, and the description still adds the result-count cap and the `fetch` handoff. The one gap is sibling disambiguation against `search_cards`, which a one-clause addition would close.

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?

There is a single parameter with 100% schema description coverage ('Card or sealed product name'), so the schema already carries the semantics. The description's phrase 'by name' restates that at a high level without adding format, matching, or normalization details, so the baseline of 3 applies.

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 (look up) and resource (trading cards or sealed products) with named supported franchises, so the agent knows exactly what domain it searches. It does not, however, distinguish itself from the sibling `search_cards`, which appears to cover overlapping territory, leaving the agent to guess which search tool to pick.

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 clear context (look up by name) and a concrete follow-up path: the returned ids are passed to `fetch`. It stops short of any when-not guidance, e.g. it never says when to prefer `search_cards` over this tool, which is the obvious ambiguity given the sibling list.

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