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

readOnlyHint=true already covers the safety profile, so the description's added value is the field-scope disclosure: 'Only work-related fields are returned (no credentials, payroll, address or birth data)'. That is genuinely useful context for an agent assembling a privacy-sensitive answer that annotations cannot convey.

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?

Three short sentences, zero filler, with the retrieval scope front-loaded before the field-exclusion note and the API detail last.

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?

No output schema exists, and the description compensates by stating what fields come back and which are withheld. For a one-parameter read this is nearly complete; only error/not-found behavior 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% and the single parameter is documented as 'The TimeTac user id.' with type and bounds. The description adds only the underlying API path (users/read?id=), which does not enrich the semantics of the parameter for an agent. Baseline 3 applies when the schema does the work.

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: 'Get one employee by user id'. The word 'one' implicitly contrasts with the listing sibling timetac_list_users, though that sibling is never named, so the distinction is inferable rather than explicit.

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?

Usage is only implied by the required 'user id' argument. There is no statement of when to prefer this over timetac_list_users, nor any note about behavior when the id does not exist.

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