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

Annotations already establish readOnly, idempotent, non-destructive and non-open-world behaviour, so the safety profile is covered. The description adds genuinely new context: the exact return fields (product_id, image_url possibly null, colours, sizes, print placements) and the no-auth requirement. It stops short of disclosing pagination or result-count limits, which matters for a search 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?

Well front-loaded: trigger first, then capability, then return shape, then constraints. The return-field enumeration duplicates the tool's output schema, which is a small redundancy in an otherwise tight four-sentence description.

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 search tool with an output schema, this covers everything an agent needs: when to invoke it, what it filters on, what comes back, and what it does not cover. Nothing required for correct invocation is missing.

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 sentence 'Finds products by free text, category, colour and size' maps cleanly onto the four parameters, and schema coverage is 75%, so the schema already does most of the work with examples for size, color and query. No extra syntax, matching behaviour or guidance on how the filters combine is added, so this is baseline territory.

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 ('Finds products') and immediately scopes it to custom-printed apparel (T-shirt, hoodie, sweatshirt, tote bag). The trailing exclusion list ('Not for mugs, posters, caps, stickers or embroidery') separates it from get_product and other catalogue siblings without the agent needing to open any schema.

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?

Opens with an explicit trigger ('Use this when the user wants their own picture, words or logo printed ... and delivered'), then gives an explicit when-not list of excluded product types. It also notes 'No account needed', removing an auth prerequisite question. Only the absence of a named sibling alternative keeps this just shy of ideal, but the intent routing is unambiguous.

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