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

Goes well beyond the annotations: it discloses optimistic-concurrency behavior (stale expected_version is rejected so unseen replies get reviewed) and the authorization requirement (editor permission, validation.write). The idempotentHint annotation already covers idempotency, but the description usefully tells the agent to supply a stable key rather than merely restating the hint.

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 dense sentences, front-loaded with the state toggling, then concurrency, then idempotency, then permissions. No filler and no repetition of schema or annotation content.

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 mutation tool, the description supplies the safety-relevant context an agent needs: permission requirements, concurrency semantics and idempotency guidance, while the output schema handles return values and annotations cover the safety profile. The one shortfall is that the two similarly named project identifiers are never disambiguated.

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 all parameter meaning. It does explain the three error-prone parameters (resolved, expected_version, idempotency_key), but leaves thread_id and especially the ambiguous pair project_id vs validation_project_id completely unexplained, which is a real invocation risk for a 6-parameter tool with 5 required.

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 and resource ('Set a shared discussion resolved or reopen it') and pins down both terminal states with 'resolved=false'. This distinguishes it clearly from the nearest siblings, validation.reply_comment and validation.create_comment, which act on the same threads.

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?

Gives concrete usage context: reopen via resolved=false, pass the latest version as expected_version, use a stable idempotency key, and requires editor permission plus validation.write. It lacks any explicit when-not or named-alternative routing (e.g. use reply_comment to add a response instead), so it stops short of a 5.

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