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

Annotations already set readOnlyHint=false and destructiveHint=true, so the mutation nature is attested. The description adds the status restriction, which is useful behavioral context, but it does not describe side effects such as overwriting fields or whether updates are partial.

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 compact and front-loaded: the first sentence names the action, and the following sentences sharpen the intended use. Every sentence earns its place without filler or repetition.

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 four-parameter tool with a required post_id, full schema coverage, an output schema, and annotations, the description covers core behavior and usage restrictions. It is slightly incomplete because it does not clarify how `posts_update` differs from the sibling `posts_edit_post`.

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%, so the schema already documents all four parameters. The description adds no parameter-level meaning beyond what the input schema provides, so the baseline 3 is appropriate.

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?

Description clearly states the verb 'Update' and the resource 'an existing post', and the status restrictions add scope. It does not adequately distinguish itself from the sibling tool `posts_edit_post`, since both appear to target existing posts.

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?

The description explicitly says draft, scheduled, and failed posts can be updated and that published posts cannot. This gives clear when-to-use and when-not-to-use context, though it does not explicitly name alternative tools or workflows for published posts.

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