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

Beyond the read-only/idempotent annotations, the description meaningfully discloses the auth limitation (not included in the free anonymous per-IP quota), the input constraint on local files, and the conditional behavior of category matches. These are non-obvious behaviors that an agent needs before calling the tool.

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?

The description is five short sentences, each contributing a distinct fact: supported inputs, unsupported inputs, output shape, parameter behavior, and auth requirements. The core purpose is front-loaded and there is no redundant 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 read-only, 4-parameter tool with an output schema, this description covers all essential decision points: input formats, the key category-match conditional, auth requirements, and expected match fields. An agent has enough context to invoke it correctly without additional inference.

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?

The input schema already documents all four parameters at 100% coverage, so the baseline is 3. The description adds value by introducing MCP image content part as an accepted form beyond what the schema lists, clarifying that url is meant as an alias concept, and explaining the include_category_matches conditional. Limit semantics are already well covered by the schema.

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 clear verb-resource pair: it identifies products from an image and links them to recalls. It enumerates accepted input forms (public HTTPS URL, base64 data URI, MCP image content) and explicitly excludes local files, which distinguishes it from text/UPC-based siblings such as search_product_recalls_by_upc.

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 clearly indicates when to use this tool: when the input is an image URL, data URI, or MCP image content. It also gives an exclusion (local files are not supported) and a prerequisite (API key or x402). It does not explicitly name alternative sibling tools for those excluded cases, so it stops short of full routing guidance.

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