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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the mutation profile is covered. The description adds value beyond that by naming the authorization requirement (admin or team member) and by stating the return value is the parent post rather than the unmerged child, which prevents a likely misinterpretation.

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 short sentences, front-loaded with the action and its effect, then the return value, then the authorization prerequisite. No redundant restatement of the title.

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 one parameter, full schema coverage, an output schema, and annotations, the definition covers what an agent needs. It does not say what happens to the child's votes, comments, or tags on unmerge, which is the kind of side effect an agent might want before calling a destructive tool, but nothing essential is 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 100% and the single parameter is already documented as 'The ID of the child post to unmerge from its parent.' The description adds nothing further about the identifier, so the baseline 3 applies.

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 names a specific verb and resource ('Unmerge a previously merged child post from its parent') and states the resulting state ('restoring it as an independent post'), which makes it clearly the inverse of the merge_posts sibling and distinguishable from it.

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 implies the precondition that the post must already be merged, and states an authorization requirement (organization admin or team member). It never names merge_posts or list_merged_posts as the related tools to consult first, so the when-to-use routing is implied rather than explicit.

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