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

Goes well beyond the readOnlyHint/idempotentHint annotations: data source is real HTTP agent-catalog checks from the last thirty days, an inclusion requires a found product plus a returned checkout link, no login/browser scan/model call is performed, results are advisory, and the flow stops before payment. The caveats that it is not a completed order and one tested product does not generalize are exactly the kind of context annotations cannot carry.

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?

Front-loaded with the core action and the query examples in the first two sentences, which is the right ordering. It is slightly over-stacked with near-repetitive disclaimers ('Results are advisory', 'This is not a completed order', 'ARC stops before payment') that could be condensed into one clause.

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 three-parameter read-only lookup with rich annotations, the description covers eligibility criteria, data recency, and safety boundaries thoroughly. The remaining gap is that no output schema exists and the description never indicates what a result row contains (store name, checkout link, check date), which an agent will want before presenting results.

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 67% and the schema already documents q and category, so baseline is 3. The description reinforces category scope with examples but never clarifies how q and category interact (union, precedence, or fallback) or what limit controls, leaving the only real semantic ambiguity unresolved.

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 and resource with its qualifying condition: finds stores whose saved check shows an AI agent reached checkout. It is clearly differentiated from point-check siblings like can_agent_checkout or precheck by being a discovery/list operation across categories.

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 two concrete sample phrasings and a scope condition ('for running shoes, beauty, clothing, home goods, or another product need'), so an agent knows the intended moment. It does not explicitly name sibling alternatives (can_agent_checkout, precheck, store_card) or when to prefer them, keeping it below a 5.

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