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

Annotations are sparse (readOnlyHint=false, destructiveHint=false), so the description carries most of the behavioral disclosure. It discloses the authorization rule (agent can edit only agent-authored comments) and the feature dependency (requires image comments feature), which goes beyond the schema and annotations. It doesn't state whether the edit is reversible or what the response contains, but the output schema exists to cover return values.

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 sentences, each carrying a distinct piece of information: the operation, the source of the id, and the permission/feature constraint. No filler or repetition of schema fields.

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?

The tool is simple (2 params, 100% schema coverage, output schema exists). The description covers the core preconditions and permission rules. The only minor gap is that it doesn't explicitly say what succeeds — e.g., whether the full updated comment is returned — but the output schema covers return structure, so the description is adequately complete.

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 100%, so the schema already documents both parameters (body and commentId). The description adds the provenance of commentId ('get its id from list_comments') and the constraint that only agent-authored comments can be edited, but it does not add detail beyond the schema's own parameter descriptions. Baseline 3 is appropriate because schema does the heavy lifting.

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 states a specific verb and resource ('Replace the body of a comment'), distinguishes from siblings by scoping to agent-authored comments only and by noting the image comments feature. The sibling list includes post_comment, delete_comment, resolve_comment, so an agent can clearly tell this edits existing comment text.

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?

Explicitly says when to use this tool (editing a comment already fetched via list_comments) and when not to (cannot edit a human's comment; only agent-authored). The preconditions — permission/feature requirement — are stated upfront, and it differentiates itself from alternatives like delete_comment and post_comment.

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