Get User by ID

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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is fully covered elsewhere. The description adds nothing beyond that — no note on what happens with an unknown or malformed ID, whether it errors or returns empty, or what fields come back.

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?

It is short and front-loaded, but the second sentence is pure duplication of the first and the title, so no sentence earns additional information. Brevity here reflects under-specification rather than disciplined editing.

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?

The tool is simple and annotations cover its read-only, idempotent nature, so little is strictly required. Still, with a sibling get_user_by_email and a list_users in the same family, the definition leaves the selection decision and the failure mode for a bad ID entirely undocumented.

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% for the single required userId parameter, which the schema itself documents as "The unique identifier of the user to retrieve." The description's "by ID" phrasing adds no format, sourcing, or validation detail beyond the schema, so the baseline 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?

The description repeats the name and title almost verbatim: "Get User by ID. Retrieves a single user by ID." It conveys the verb (retrieve) and resource (user) but offers no differentiation from nearby siblings such as get_user_by_email or list_users, so an agent must infer which retrieval tool applies.

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?

There is no guidance on when to use this tool versus get_user_by_email or list_users, and no stated preconditions (e.g., that a valid user ID is required). The only implied usage is "when you have an ID," which comes from the parameter name, not the description.

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