list_commit_statuses

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

The description explicitly states 'It is read-only and does not mutate GitLab data' and lists error conditions ('missing resources, invalid identifiers, insufficient permission, and rate limits are returned as errors'). This goes beyond the readOnlyHint annotation and provides concrete behavioral expectations.

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 verbose and repetitive. For example, it states 'It is read-only and does not mutate GitLab data' and later repeats similar guidance about identifiers. It could be shortened to the core purpose and a brief usage note. The lack of conciseness reduces clarity.

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?

It covers the key aspects: purpose, usage distinction, read-only nature, error behavior, and parameter handling. It does not explain the return format, but since no output schema is provided, that's acceptable. It is relatively complete given the tool's scope.

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 schema covers 100% of parameters with descriptions, so the baseline is 3. The description adds only a generic reminder about project_id/group_id and pagination, which is largely redundant with the schema. It does not clarify any parameter semantics beyond what the schema already provides.

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 'List statuses for a commit' – a specific verb, resource, and scope. It also explicitly contrasts with a 'get tool' for a single resource, distinguishing it from potential sibling tools like get_commit or get_merge_request_status.

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?

It provides direct guidance: 'Use this for a collection of resources; choose the corresponding get tool when you already know the single resource to inspect.' This is helpful, though it doesn't name a specific alternative tool. It also mentions pagination and required identifiers, but in a generic way.

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