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

With no annotations, the description carries the full transparency burden. It discloses the return fields, the prerequisite call to get_connected_accounts, the default-connection behavior, and even the token cost. It does not mention error behavior for a missing user, but for a simple read operation it is appropriately transparent.

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 four short sentences, front-loaded with the purpose, then usage, output, and cost. Every sentence adds distinct information with no fluff or repetition.

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?

Despite having an output schema, the description still lists the specific returned fields, which is helpful. It covers the prerequisite, multi-account targeting, default behavior, and cost. For a straightforward get-by-id tool, the context is complete and no critical gaps are evident.

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 coverage is 100%, so the baseline is 3. The description mainly reiterates the schema's explanation of clerk_instance_id ('target a specific connection, or omit it to use the default account'), adding little new semantic detail. The 'call clerk.get_connected_accounts first' instruction is useful but is more of a usage prerequisite than a parameter semantic.

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 opens with 'Retrieve one Clerk user by id,' which clearly specifies the verb and resource. It distinguishes this tool from siblings like list_users (which lists many) and count_users, and the mention of 'one ... user by id' makes the single-record intent unambiguous.

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?

Provides explicit guidance: 'Call clerk.get_connected_accounts first' and explains how to handle the optional clerk_instance_id—pass it for a specific connection or omit for the default. This goes beyond vague context and gives clear step-by-step instructions for when and how to use the tool correctly.

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