Edit image

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

Goes meaningfully beyond the annotations by disclosing that the source is never overwritten, that outputs land in the output folder with a .json sidecar, and that paths plus small previews come back. It does not cover provider/credential constraints or cost/rate behaviour, but for a mutation tool flagged openWorld this is solid added context consistent with destructiveHint=false.

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?

Two sentences, zero filler: the action and examples come first, then the side-effect and return-format guarantees. Every clause carries information an agent would otherwise lack.

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?

With no output schema, the description usefully compensates by stating what is returned (paths and previews) and where files land. Minor gaps remain around the mask/provider restriction and any length or content limits on the prompt, but the specification is sufficient to invoke the tool 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?

Schema coverage is 100%, so every one of the 8 parameters (including mask, references, transparent, out_name) already carries its own description; the description adds nothing about individual parameters. Baseline 3 applies since the schema does all the semantic work.

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 ('Change an existing image') and immediately grounds it with four concrete instruction examples, which makes the distinction from the generate_image/generate_set siblings apparent without naming them. An agent can tell this transforms an existing file rather than creating one from scratch.

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 framing 'an existing image' implicitly signals when to reach for this over generate_image, and the examples clarify the kind of prompt that works. But there is no explicit when-to-use/when-not statement and no reference to the siblings by name, so the routing decision is left to inference.

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