whoami

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

With no annotations provided, the description carries full behavioral burden. It explains the API call (GET /user), session token resolution, and sudo-impersonation behavior. This goes beyond basic purpose and adds valuable transparency about how the tool works internally.

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?

Two sentences: first states purpose, second adds context and usage. No wasted words, front-loaded with critical information. Every sentence earns its place.

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 zero parameters and presence of output schema, the description explains return value indirectly (user record) and covers sudo-impersonation nuance. For a simple identity tool, this is fully complete.

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 zero parameters, so description adds no param info—this is fine. With 100% schema coverage (trivially) and baseline 4 for 0-param tools, the description does not need to add parameter details.

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 returns the current Looker user, with specific verb ('Return'), resource ('Looker user'), and context ('MCP session'). It distinguishes itself from sibling tools like create_dashboard or delete_look by focusing on authentication identity.

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 when to use the tool: when there are multiple similarly-named users and confirmation of which user the MCP is operating as is needed. It lacks explicit when-not-to-use or alternative tools, but the context is clear and adequate for a simple identity tool.

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