Zitadel MCP

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

Annotations cover basic traits (non-readOnly, non-idempotent, non-destructive), and the description adds useful context about validation behavior. However, it doesn't disclose additional details like authentication requirements, rate limits, error conditions, or what happens on duplicate grants, which would enhance transparency 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 a single, well-structured sentence that efficiently conveys the core action and a key behavioral trait (validation). It's front-loaded with the main purpose and avoids unnecessary details, making it highly concise and effective.

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 and moderate complexity (3 parameters, validation logic), the description is adequate but not complete. It covers the purpose and validation but lacks details on return values, error handling, or prerequisites, which would help an agent use it more effectively.

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%, providing clear documentation for all parameters. The description adds minimal value beyond the schema by implying validation for 'roleKeys' but doesn't elaborate on semantics like role key formats or project defaults. This meets the baseline for high schema coverage.

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 ('Assign roles to a user by creating a grant') and resource ('user'), making the purpose evident. However, it doesn't explicitly differentiate from sibling tools like 'zitadel_create_project_role' or 'zitadel_remove_user_grant', which would require more specific language about scope or operation type.

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 implies usage context by mentioning validation ('Validates that the roles exist in the project before granting'), suggesting it should be used when assigning existing roles. However, it lacks explicit guidance on when to choose this tool over alternatives like 'zitadel_create_project_role' (for creating roles) or 'zitadel_remove_user_grant' (for revoking grants), leaving some ambiguity.

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