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

Annotations already declare readOnlyHint=false, openWorldHint=true, idempotentHint=false and destructiveHint=false, and the description adds context beyond them: 15-30 second latency, watermark on previews, clean file only on order, and the 10-design free limit. It also discloses the non-idempotent retry policy, which the annotations alone would not convey.

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?

Four sentences, each load-bearing: capability and output, watermark/caveat, input spelling instruction, and quota/retry behavior. Front-loaded with the verb and result, no 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?

No output schema exists, yet the description names the return payload (image plus design id plus order link), the latency, and the retry path — everything an agent needs to call it and interpret the result. Nothing material 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?

Schema description coverage is 100%, so baseline is 3; the description adds real value by instructing 'Say what the patch shows and any text on it, spelled exactly' and clarifying that with a reference image the description becomes adaptation guidance. It doesn't restate width/height/patchType constraints, which the schema already handles.

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 ('Generate a production-ready custom patch design from a description') and immediately distinguishes itself from siblings by noting it returns a design id 'for edits' and an 'order link'. An agent can separate this from edit_patch, order_link, quote_patch and sign_in_link without opening 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?

Gives explicit when-to-use conditions (from a description, optionally a reference image), a concrete retry rule ('If the result says the service was busy, call it once more with the same input'), and the free-quota/auth path ('10 free designs, then the user signs in with the link from sign_in_link'). This is routing-grade guidance.

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