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

With annotations already declaring readOnlyHint=true and destructiveHint=false, the description adds meaningful behavioral context: the tool fetches the full user list and returns the matching user because the public API lacks a direct GET /users/{id} endpoint. It does not describe not-found behavior or pagination, but the implementation caveat is a useful disclosure beyond annotations.

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 two tight sentences with the primary action front-loaded, followed by necessary implementation context. There is no filler and every sentence contributes useful information.

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, has complete schema descriptions, and includes an output schema, so the description does not need to explain return values. It covers the key implementation caveat, though it could mention not-found behavior or workspace scoping more explicitly.

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%, so both the id and workspace_id parameters are already documented in the input schema. The description reinforces that lookup is by user ID but adds no syntax or workspace-scoping details beyond the schema, making the baseline 3 appropriate.

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 uses a specific verb and resource ('Retrieve a specific user by ID') and clearly scopes it to a single user from the account user list, distinguishing it from the sibling get_all_users tool. An agent can immediately tell this is for ID-based lookup rather than listing all users.

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?

It clearly indicates use for retrieving one user by ID and explains that the public API only exposes GET /users, implying the full-list fallback. However, it does not explicitly name get_all_users as the alternative for listing users, so the when-not condition is only implicit.

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