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

Annotations already establish readOnly, idempotent, non-destructive, and closed-world behavior, so the bar is lower. The description adds genuinely new context beyond them: the required 'users:read' scope and the fact that a single object (not a collection) is returned.

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?

Three short, front-loaded sentences with no redundancy: purpose, return shape, then auth requirement. Every sentence carries distinct information and nothing is padded.

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 single-object read with no output schema, the description partially compensates by naming the returned fields (name, email, role) and the auth scope. It is adequately complete, though error/not-found behavior is left unstated, which is the only remaining small gap.

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% and the schema's own parameter note ('Clerk user ID string') is actually more precise than the description's 'user ID'. With the schema doing the heavy lifting and the single required parameter fully documented, the baseline of 3 applies.

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?

States a specific verb and resource ('Get a specific organization member by their user ID'), which is clearly narrower than the sibling list_users. It does not explicitly name list_users as the alternative for discovery, so it falls short of the sibling-differentiating bar for a 5.

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 phrase 'by their user ID' implies the precondition that the caller must already hold a valid ID, which is the only usage context offered. There is no explicit when-to-use versus list_users guidance, no exclusion for bulk retrieval, and no note on what to do if the ID is unknown.

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