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

Goes well beyond the annotations: the edit history retention qualifies what 'destructive' means here, 'same text again is `unchanged`' concretely explains idempotency, and the concurrent-edit conflict rule plus mention-notification behavior are otherwise undiscoverable. It even names the mirrored REST endpoint and return shape, which matters since there is no output schema.

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?

Front-loaded with the action and key, then layered with constraints, with no filler sentences. It is dense (endpoint mirror and return shape in the same paragraph) but every clause carries operative information.

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 with no output schema, it covers auth, reversibility, idempotency, concurrency, notifications, and the return shape. The only omission is the optional thread parameter, which the schema already types adequately.

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 80%, so baseline is 3. The description restates the comment-id keying and confirms the body semantics, but adds nothing about the optional nested `thread` object (kind/number) that the schema leaves thin on purpose.

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+resource ('Replace the text of a comment'), the scope ('issue or pull request'), and the lookup key ('by comment id'). This clearly separates it from creating tools like gluecron_comment_issue/gluecron_comment_pr and from gluecron_delete_comment.

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?

Names the authorization contract ('Its author or a repository writer only'), which tells the agent when the call will succeed. It does not explicitly point to alternatives such as delete_comment or re-commenting when the edit is not permitted, so it stops slightly short of full routing guidance.

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