create_merge_request_discussion_note

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

With only a minimal `openWorldHint` annotation, the description carries the burden of disclosing side effects. It explicitly states that the operation 'creates remote review content', requires note permission, and can return errors for missing discussion/position/permission. This goes beyond a simple 'creates a note' by specifying permission and failure modes. A slight gap is the lack of mention of reversibility or notification side effects, but the core mutation behavior is clear.

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 two sentences with no extraneous words. It front-loads the core action, then provides sibling differentiation and side-effect/error information. Every sentence earns its place, and the structure is efficient.

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?

Given the tool's moderate complexity (5 params, all required ones documented), the description covers the essential aspects: what it does, when to use it, permission requirements, and return/error behavior. It does not have an output schema, so mentioning the return value is helpful. It could arguably include more about the `created_at` parameter, but the schema covers that. Overall, an agent has enough context to call it correctly.

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 all parameters have descriptive text. The description does not add extra meaning beyond the schema, such as explaining the relationship between discussion_id and merge_request_iid. However, since the schema already covers parameter semantics, a baseline of 3 is appropriate—the description simply doesn't need to repeat it.

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 clearly states the action ('Add a new discussion note to an existing merge request thread') and differentiates it from siblings by explicitly naming `create_merge_request_thread` and `create_merge_request_note` with their distinct purposes. This removes any ambiguity about which tool to use.

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 explicit when-to-use and when-not-to-use guidance by stating 'Use this to reply inside an existing merge request discussion' and contrasting it with starting a new thread or a top-level note. It also mentions permission requirements and possible errors, giving the agent a clear decision frame.

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