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

Annotations already declare destructiveHint=true and non-idempotence, but the description adds genuinely new behavioral context: the previous image is retained for undo, the CMS push affects only the featured image, and the first call is non-mutating and returns a summary plus confirmToken. It stops short of covering token expiry, permission requirements, or failure 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?

Three tight sentences, front-loaded with the action and followed by consequence, undo path, and the confirmation flow. Every sentence carries information, though the confirmation mechanics could be compressed into the schema-referenced field.

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 destructive 4-parameter mutation with no output schema, the description covers the key agent needs: what changes, what is preserved, how to reverse it, and that a two-step confirm gate exists. It omits error/edge behavior and the content of the summary, which keeps it from being fully complete.

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 only 50% (site and confirmToken are documented; postId and candidateId are bare strings). The description partially compensates by implying candidateId is a generated/uploaded candidate and postId is a post already on the CMS, but it adds no format, ID-source, or selection detail beyond that inference.

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 first sentence names a concrete verb (makes one candidate the post's image) plus the resource and the CMS side effect, which cleanly separates it from siblings like upload_post_image, get_post_image, and get_photo_candidates. It also states the scope restriction (image only, text untouched).

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 routes the agent: use revert_post_image to undo, and it explains the required two-call confirmation sequence with confirmToken. It does not explicitly state prerequisites (e.g. that a candidate must first exist from get_photo_candidates) or when not to use it, so it falls short of a full when/when-not guidance.

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