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

Annotations already declare the safety profile (not read-only, not idempotent, not destructive, closed-world). The description adds genuine beyond-annotation context: images/videos become media blocks while other files become a link, and it explicitly does not publish or alter existing delivery snapshots. It stops short of explaining the revision-conflict error 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?

Four short, front-loaded sentences with no filler; the 'Use when' clause leads and each subsequent sentence adds scope or effect. Slightly clipped phrasing ('Read the post revision first') costs it the top mark.

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?

An output schema exists, so return values need no explanation, and annotations cover safety. For a three-parameter mutation tool the description conveys trigger, prerequisite, side effects, and scope boundaries; only the concurrency-failure contract and the sibling distinction are 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 description coverage is 0%, so the description must carry parameter meaning. It partially compensates by qualifying mediaId as a 'finalized owner mediaId' and hinting at expectedRevision via 'Read the post revision first', but it never defines formats, the revision-mismatch contract, or postId/postId-vs-draft 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?

The description states a specific verb and resource: adding a finalized owner mediaId to a working post, with concrete effects (media blocks vs link). It is clear enough to distinguish from generic post tools, but it never differentiates itself from the near-identical sibling attach_media_to_draft, which is a real ambiguity here.

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 an explicit trigger ('Use when adding a finalized owner mediaId to a working post') plus a prerequisite ('Read the post revision first'). However, it offers no exclusions or alternative routing, notably failing to say when to use this versus attach_media_to_draft.

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