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

readOnlyHint=true already tells the agent this is a safe, non-mutating read, so the safety burden is covered. The description adds that it returns 'status and results', hinting at an async polling pattern, but does not explain possible states (pending/failed/complete), whether polling is required, or how partial results are represented.

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 tight sentences with the primary action front-loaded and the prerequisite second. No filler, no redundancy with the title or 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 no output schema, the description is the only place to learn what comes back, and 'status and results' is thin for a polling-style fetch tool: it omits the possible status values and what a caller should do when the generation is not yet ready. The input side is adequately covered via the schema.

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% and the sole 'id' parameter is already documented as the request ID from a previous image generation call. The description marginally enriches this by naming the specific tools that produce the ID, but adds no format or validation detail beyond the schema. Baseline 3 applies when the schema carries the semantics.

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 (retrieve) and resource (status and results of an image generation request), which clearly separates it from generic fetchers like fetch-generation and from the other media fetchers (fetch-video, fetch-audio). It does not, however, explicitly name a sibling it is not, so the differentiation is implied by the 'image generation request' scope rather than stated.

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?

Explicitly says to use the request ID returned from text-to-image, image-to-image, or inpaint-image, giving the agent the prerequisite and provenance of the input. It stops short of when-not guidance (e.g., which fetch-* to use for non-image generations), so no explicit exclusions are provided.

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