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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the safety profile is covered, and the description adds two genuinely new facts: the operation consumes credits and it is asynchronous, returning a project id to poll. It stops short of covering tier requirements or failure behavior, but that is a modest gap.

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, both front-loaded with the highest-value facts (what it makes, what it costs, what it returns) and no redundant restatement of the schema.

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 an output schema present and a fully documented parameter schema, the description only needs to cover cost and the async handoff, both of which it does. Nothing an agent needs to call it correctly 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 coverage is 100%, with the model, resolution, and style enums exhaustively documented in the schema itself. The description only summarizes ("model, output size and image count options") without adding syntax or trade-off detail beyond the schema, which is the expected baseline.

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 opens with a specific verb+resource ("Generates one or more images from a text prompt") and the phrase "from a text prompt" implicitly separates it from sibling editing tools like edit_image and upscale_image. It also names the downstream sibling wait_for_image_project, so an agent understands the tool's position in the pipeline.

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 supplies useful context ("Costs credits", follow-up via wait_for_image_project) but gives no explicit when-not-to-use guidance or mentions of overlapping siblings such as generate_headshot or create_meme. Usage is implied rather than stated.

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