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

Annotations declare readOnlyHint=true, so the safety profile is already covered. The description adds value beyond that by framing the call as 'cheap' (implying a lightweight, low-cost read) and by tying the returned UserId to downstream use in AssignedTo. No auth prerequisites or rate limits are mentioned, but little else is needed for a zero-argument read.

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, both front-loaded with the return shape first and the motivation second. The trailing 'LACRM: GetUser.' is a minor label but no sentence is wasted.

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?

With no output schema, the description carries the burden of describing the return value and does so precisely (UserId, name, email, timezone). For a zero-param read tool with annotation-covered safety, nothing an agent needs to call it correctly 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 tool takes zero parameters, so there is nothing for the schema to describe and no gap for the description to fill. Baseline 4 for a no-parameter tool.

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 ('Return the user who owns this API key') and enumerates exactly which fields come back (UserId, name, email, timezone). The scope qualifier ('who owns this API key') cleanly separates it from the sibling lacrm_list_users, so an agent can choose without inspecting either schema.

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?

Gives two concrete use cases: a cheap key-validation check, and obtaining the UserId needed for AssignedTo. It doesn't explicitly name lacrm_list_users as the alternative when a full roster is needed, so it stops short of full when/when-not routing.

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