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

The annotations only indicate readOnlyHint=false and destructiveHint=false, so the description carries the responsibility for behavior. It adds important behavioral detail beyond the annotations: the operation costs credits, is billed at the target resolution, and produces a new generation rather than modifying the source. It does not mention whether the operation is asynchronous or what the return shape is.

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?

Three short sentences with no filler. The core action is front-loaded, the critical cost warning is visibly flagged, and the creation semantics are stated last without redundancy.

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 simple two-parameter tool with no output schema, the description covers the essential operational context: what it operates on, what it produces, where the result goes, and that it has a credit cost. The only notable gap is the lack of explicit return/async behavior, which could matter when chaining calls.

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 schema coverage at 50%, the description compensates for the undocumented generation_id by tying it to an 'existing generation' and clarifying the project scoping. It reinforces resolution as the target/driver of cost, and the schema's enum covers the concrete values.

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 identifies a specific operation—re-rendering an existing generation at a higher resolution—and clarifies that it creates a NEW generation within the source project. This distinguishes it from sibling generation and image-edit tools like generate_image, restyle, or expand_image, even without naming them.

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?

It clearly implies when to use the tool: for an existing generation that needs higher resolution. It does not explicitly name alternatives or exclusion criteria, but the 'existing generation' and 'source's own project' context provides clear handling guidance.

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