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

The annotations already establish that this is a read-only, idempotent, non-destructive operation. The description adds useful behavioral context beyond them: image-change limits are tied to Pro and above, and the response indicates whether a generation is still running, which drives polling behavior.

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 three dense sentences with no wasted language. It front-loads what the tool returns, then gives the polling workflow and follow-up action.

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 carries most of the burden and does well by enumerating the returned image information and generation state. It could more fully specify the response shape or candidate id format, but it provides enough to call 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 50%: `site` is documented in the schema, while `postId` has no description there. The description does not add meaning to either parameter, though both are simple required identifiers and the tool's context makes `postId` reasonably clear.

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 uses a specific retrieval verb and names the exact resource: a post's image panel, including featured image, in-article images, candidates, remaining changes, and generation status. It is clearly distinguishable from write-side siblings such as apply_post_image, upload_post_image, and revert_post_image.

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 gives explicit workflow guidance: poll after generate_post_image until `generating` is false, then call apply_post_image with a candidate id. This tells the agent both when to call this tool and what to do next, with named alternatives.

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