check_iam_permissions

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

With no annotations provided, the description must carry the behavioral burden. It states that it returns a list of permissions for the current user, implying a read-only check, but does not explicitly say it makes no modifications, what permission types are included, or any error conditions. It adds some context by specifying scope to the current user and project, but lacks richer behavioral disclosure.

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 concise and well-structured: a one-line purpose statement followed by Args and Returns sections. Every sentence adds value, and the essential information is front-loaded. There is no wasted text.

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 simple read-only tool with one parameter and no output schema, the description covers the core aspects: what it does, the parameter, and the return type. It lacks some nuance (e.g., whether permissions are project-level or resource-level), but it is sufficiently complete for a basic check operation.

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 provides only a title 'Project Id' with no description (0% coverage). The description compensates with an Args section explaining that project_id is 'The ID of the GCP project to check permissions for.' This adds meaningful semantics for the single parameter, though it could be more detailed about expected formats.

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 tool's purpose with a specific verb ('Check') and resource ('IAM permissions') scoped to 'the current user in a GCP project.' This distinguishes it from siblings like add_iam_policy_binding (which modifies permissions) and get_role_permissions (which lists permissions for a role).

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?

Usage is implied by the purpose: if you need to check the current user's permissions in a project, use this tool. However, there is no explicit guidance on when to use it versus alternatives, no exclusions, and no mention of related tools like list_roles or get_role_permissions.

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