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

With annotations declaring a non-readOnly, non-idempotent mutation, the description still adds meaningful behavior: the call is free, it is quota-limited (3/image plus a monthly account allowance), and it returns the new image id. The quota detail is especially valuable since a non-idempotent retry consumes allowance, and the description implies but doesn't state that retries cost quota.

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 purpose, then limits, then fallbacks, then parameter guidance and an example — a sensible information hierarchy with no filler. The prose is somewhat compressed and run-on, but every sentence carries operational content.

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-required-parameter mutation with no output schema, the description covers cost, quota limits, fallback tools, return value (new image id), and the input-gathering step. An agent has everything needed to decide and call correctly without guessing.

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 description compensates by telling the agent to pass the user's own words as note and giving a full worked example covering all three required parameters. It does not explain the reason enum values beyond what the schema already lists, so it is incremental rather than exhaustive.

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?

A specific verb and resource plus the exact failure conditions it targets (product shape/label/colour/logo mismatch or wrong text). This makes it trivially distinguishable from regenerate_image and edit_image, which are named explicitly as the paid alternatives.

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 an explicit when-to-use condition, hard limits (3 per image, monthly allowance per account), and a named fallback (regenerate_image or edit_image at 1 credit) for when those limits are hit. It also instructs the agent to ask the user what is wrong first, which is actionable context, not just background.

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