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

Annotations already indicate readOnlyHint=false, idempotentHint=true, and destructiveHint=false. The description adds meaningful behavioral context: the requester is added to the allowlist, the effect is view access, and rejected requests (forbidden, plan_limit, not_found) make no change. This goes beyond the annotations and clarifies the tool's side effects and no-op cases. It doesn't fully describe all possible failure modes or permission errors, but it is strong for a mutation tool.

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, front-loaded with the core action and effect, then the discovery workflow and permission/edge-case notes. Every sentence earns its place; there is no fluff or repetition of schema content.

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?

For a mutation tool with no output schema, the description covers the action, effect, prerequisite discovery step, permission restriction, and no-op cases. It doesn't describe the response format or what happens on success beyond the allowlist addition, but the annotations cover idempotency and non-destructiveness. The main gap is the lack of explicit error/response details, but the description is otherwise complete enough for an agent to invoke 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 the schema already documents all three parameters. The description adds value by explaining the purpose of request_id (find it via list_access_requests) and the workspace_id semantics are already well-covered in the schema. The description doesn't repeat parameter details, but it does connect request_id to a concrete discovery workflow, which is useful.

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 states a specific verb ('approve'), a specific resource ('pending access request'), and the concrete effect ('requester is added to the site's allowlist and can then view it'). It also distinguishes itself from the sibling deny_access_request by focusing on approval. This is a clear, non-tautological definition.

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 explicitly tells the agent when to use this tool: to approve a pending access request, and how to find the required request_id via list_access_requests. It also states the admin/owner-only restriction and notes that rejected requests make no change, which helps the agent decide whether to call this tool or handle the request differently.

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