GitLab MCP Server

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It states 'Modify an existing merge request thread note', which implies a mutation operation, but lacks critical details: it doesn't specify required permissions, whether changes are reversible, potential side effects (e.g., notifications), or error conditions. For a tool with 6 parameters and no annotation coverage, this is a significant gap in transparency.

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, efficient sentence with zero waste—it directly states the tool's purpose without fluff or repetition. It's appropriately sized for a tool with a clear name and well-documented schema, making it easy to parse and understand quickly.

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 complexity (6 parameters, mutation operation) and lack of annotations and output schema, the description is incomplete. It doesn't address behavioral aspects like permissions, side effects, or return values, which are crucial for a tool that modifies data. The high schema coverage helps with parameters, but overall context for safe and effective use is lacking.

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?

The input schema has 100% description coverage, with each parameter clearly documented (e.g., 'Project ID or complete URL-encoded path to project'). The description adds no additional meaning beyond what the schema provides—it doesn't explain parameter relationships, dependencies, or usage examples. Given the high schema coverage, the baseline score of 3 is appropriate, as the 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?

The description clearly states the action ('Modify') and the resource ('an existing merge request thread note'), which is specific and unambiguous. It distinguishes this from sibling tools like 'create_merge_request_note' or 'update_issue_note' by specifying it's for modifying existing notes, not creating new ones or updating other entities. However, it doesn't explicitly differentiate from all siblings (e.g., 'update_issue_note' has a similar pattern), so it's not a perfect 5.

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 no guidance on when to use this tool versus alternatives. It doesn't mention prerequisites (e.g., needing an existing note), exclusions (e.g., not for creating notes), or compare it to similar tools like 'update_issue_note'. The agent must infer usage from the name and context alone, which is insufficient for clear decision-making.

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