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

readOnlyHint=true already covers the safety profile, so the description's contribution is the returned field set and the reference-expansion behavior of include. It omits auth requirements, error behavior for unknown ids, and rate limits, so it adds context but is not rich.

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 compact sentences, front-loaded with the verb and resource, then the return fields, then the include hint and endpoint. No filler and nothing buried.

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 usefully enumerates the returned fields and explains include's expansion role, which is what an agent needs to call it correctly. Minor gaps remain (error cases, whether include values are validated), but nothing critical 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?

Schema coverage is 100%, so both user_id and include are already documented with types, bounds, and examples. The description reinforces include with an example ('identity_email,organization') but adds no syntax or default beyond what the schema states, so 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?

States a specific verb+resource ('Fetch one user by id') and enumerates the fields returned, which cleanly separates it from siblings like kayako_list_users, kayako_create_user, and kayako_get_me. An agent can identify the operation without opening the 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?

The 'by id' framing implies usage (single-record lookup when you already have an id), which is enough to distinguish it from list_users. However, it never explicitly says when to prefer it over kayako_get_me or kayako_search, and names no alternatives.

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