set_repo_collaborator_permission

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

With no annotations, the description carries full burden. It discloses that this is a write operation and is blocked under read-only flag. It lists valid permission levels. It does not detail authentication requirements or behavior on update vs add, but provides sufficient transparency for safe invocation.

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?

Description is concise (3 sentences) and front-loaded with the purpose. However, it lacks structure (e.g., bullet points) and could be more organized, but still 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 4 parameters, no annotations, and no output schema, the description covers core behavior and one parameter but omits details for other parameters and return value. It is minimally adequate but leaves gaps.

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 0%, so description must compensate. Only the 'permission' parameter is explained with valid values. The other three parameters (owner, repo, username) are not described, leaving ambiguity (e.g., is username the collaborator or owner?).

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 clearly states 'Add or update a collaborator's permission on a repo', which is a specific verb-resource pair. It distinguishes from siblings like get_repo_permission (read) and set_team_repo_permission (team vs collaborator).

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?

Declares 'WRITE OPERATION' and 'Blocked unless GITHUB_MCP_READ_ONLY=false', providing when-not-to-use guidance. However, it does not explicitly compare with sibling set_team_repo_permission, though the name differentiates collaborator vs team.

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