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

Beyond the annotations, the description discloses the credit cost model, that dry_run returns cost without spending, that images without the product are copied free, that each colour becomes its own image set, and that new image set IDs are returned for follow-up. These details materially help the agent understand the operation’s side effects and downstream flow.

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 information-dense and front-loads the purpose, cost caveat, and example. The sentence structure is somewhat compressed with parentheticals and semicolons, but every sentence carries actionable information and nothing is redundant.

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 multi-step, credit-spending image-generation tool with no output schema, the description covers purpose, cost behavior, dry-run workflow, return value, and follow-up action. An agent has enough information to invoke it safely and correctly.

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?

With 50% schema coverage, the description compensates well for key parameters: it explains colours, hex, photo_base64, dry_run, and all_images behavior. It does not explain the nested 'note' field or the maxItems limit, but it adds substantial meaning beyond the schema for the parameters that drive correct invocation.

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 specific verb and resource: it makes a finished image set’s main image in other product colours. It also clarifies the exact scope ('only the product’s colour changes, the scene and text stay') and the variant behavior ('all_images true makes every image'), which separates it from generic image-editing tools.

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 gives clear when-to-use context ('for colour variations and swatches') and explicit procedural guidance: call dry_run true first, report the cost, then call again without it. It does not name sibling alternatives or state when not to use this tool, but the usage sequence is unambiguous.

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