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

readOnlyHint=true already establishes this as a safe read, so the bar is lower. The description adds useful content about what the record contains and how include expands references, but says nothing about error/not-found behavior or the shape of the returned payload.

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 tight sentences with the core purpose front-loaded and the return-field inventory following. The trailing 'Kayako: GET /api/v1/users/{id}.json' endpoint note adds little for an agent and is the only near-wasteful element.

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?

For a simple read-by-id tool with readOnlyHint, a fully documented two-parameter schema, and no output schema, the description does well by enumerating the fields an agent receives and explaining include expansion. Only error/not-found handling is unaddressed.

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 both user_id and include are already documented with their own examples. The description's include='identity_email,organization' example is mildly useful but largely overlaps the schema, so this is a baseline 3.

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 ('Fetch one user by id') and even enumerates the fields returned, which clearly separates it from kayako_list_users and kayako_get_me in spirit. It stops short of naming those siblings explicitly, so the differentiation is inferred rather than stated.

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 'fetch one user by id' framing implies this is the single-record retrieval path, but the description never says when to prefer it over kayako_list_users (bulk) or kayako_get_me (self). No prerequisites or when-not conditions are given.

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