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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the trailing 'Read-only' adds nothing. The only extra behavioral content is the return shape (merchant description + all shop offers), and with an output schema present even that is largely redundant. Adequate but adds little beyond structured metadata.

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?

A single sentence that front-loads the verb and the key input provenance, then enumerates the returned content. No filler, no restated title.

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 annotations covering the safety profile and an output schema covering return structure, the description only needs to establish purpose and input provenance, which it does. It leaves the zip/market trade-off entirely to the schema, which is acceptable but slightly thin for a 3-parameter tool.

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% because product_id has no schema description; the description fills that exact gap by specifying the product_id must come from a prior search_catalog result. zip and market are already documented in the schema, so the description's contribution is targeted and useful, though it adds no detail about how zip and market interact.

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 ('get product') and precisely scopes the output: the merchant's description plus every shop's offer. It also explicitly traces its input origin ('the product_id search_catalog returned'), which cleanly separates it from the search_catalog sibling.

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 makes the calling context clear: this is the follow-up step that consumes a product_id produced by search_catalog, which is exactly the when-to-use guidance an agent needs. It stops short of naming when not to use it (e.g., bulk lookup) or what to do if no product_id is available, so it is not a full 5.

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