Update merge request note

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

Annotations already indicate a non-read-only, non-idempotent write operation. The description adds only the scope 'replace the body' and does not disclose side effects such as notifications (openWorldHint=true) or permission requirements. It does not contradict annotations, but adds minimal behavioral context beyond them.

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 a single concise sentence with no filler or repetition. It front-loads the action and clearly states the target resource.

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 and has an output schema, so return values need not be described. However, with five required parameters and only 40% schema coverage, the description leaves parameter relationships and acquisition context implicit. Sibling tool names like list_merge_request_discussions provide some assistance, but the description itself does not explain how to obtain discussion_id or note_id.

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 only 40%, covering project and merge_request_iid. The description provides no guidance on discussion_id, note_id, or body semantics. With low schema coverage, the description should compensate for the undocumented parameters, but it does not.

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 uses a specific verb ('Replace') and clearly identifies the resource ('body of a note or reply inside a GitLab merge request discussion'). This clearly distinguishes it from sibling note operations like delete_merge_request_note and reply_merge_request_discussion.

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 provides clear context for when to use the tool: to replace the body of an existing note or reply in an MR discussion. However, it does not explicitly name alternatives or exclusions (e.g., 'for issue notes use update_issue_note'), 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.