impersonate_user

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

No annotations are provided, so the description must fully disclose behavioral traits. It fails to mention side effects (e.g., does it modify anything?), authorization requirements, or output behavior. For a security-sensitive tool like impersonation, the lack of transparency is a critical deficiency.

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 extremely brief (2 words), which is under-specified rather than concise. It lacks any structure or additional context that would help an agent. A concise description should pack more information into a small space, not omit necessary details.

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 the complexity of impersonation (likely involving authentication and authorization), the description is completely inadequate. There is no output schema, and critical information about preconditions, side effects, and return values is missing.

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 has 100% coverage with descriptions ('Realm name', 'User ID'), and the tool description adds no additional meaning. According to the guidelines, with high schema coverage, the baseline is 3, and no extra value is provided.

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 'Impersonate a user.' clearly identifies the action (impersonate) and resource (user), but it lacks specificity about what impersonation entails in this context, such as whether it creates a session, returns a token, or modifies state. Among siblings, no other tool has 'impersonate' in its name, but the description does not differentiate it from other user-related actions like get_user or update_user.

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 provides no guidance on when to use this tool versus alternatives. It does not specify prerequisites, such as whether the caller needs admin privileges, or the context in which impersonation is appropriate. Given the sensitivity of impersonation, this omission is significant.

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