get_user

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

No annotations are provided, so the description carries full responsibility. It accurately notes the tool returns a single structured record and returns custom profile fields. However, it does not mention any error conditions (e.g., what happens if the user is not found, or if multiple identifiers are provided) nor read-only behavior—but the description of 'Fetch' implies idempotent read. While it could be more thorough, it is clear and truthful.

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 three sentences long: first states the action and search criteria, second gives usage constraint, third describes the return. Every sentence adds necessary information without excess. No wasted words.

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?

Given that there is no output schema, the description compensates by stating that a single structured user record with custom profile fields is returned. The 4 parameters are all documented in the schema with full coverage, so no additional parameter explanation is needed. The description covers essential usage and return shape, making it complete for a straightforward fetch operation.

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 the baseline is 3. The description adds no new semantics beyond the parameter schemas but reinforces that exactly one identifier should be used. No additional format or validation hints are needed, so the score holds at baseline.

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 clearly states the action ('Fetch'), the target resource ('one Moodle user'), and the identification methods ('by exact ID, email, or username'). It distinguishes this tool from sibling tools like 'list_users' or 'search_users' by specifying that it returns a single user based on exact match, not a list or fuzzy search.

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 description explicitly says to provide exactly one of the three identifiers (id, email, or username), which guides usage. It does not explicitly compare to alternatives like search_users or list_course_users, but the context of siblings and the tool's purpose imply it is for a direct, exact lookup rather than discovery.

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