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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered; the description adds the concrete endpoint (GET /clients/{id}) and the fact that no list/search capability exists anywhere in the API. It does not say what happens on a missing/invalid visitor id or whether external integration data requires extra access, leaving some operational gaps.

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 sentences, front-loaded with the resource, then the response payload, then the id requirement and endpoint. The long field enumeration earns its place because there is no output schema, though the id sentence partially duplicates the schema.

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, describing the returned fields is the right compensation, and the description covers them thoroughly plus the endpoint. Missing only edge-case behavior (visitor not found, empty visit history) that an agent would need to interpret a sparse response.

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's schema description already spells out clientId (ChatraSetup.clientId) and the webhook client.id. The description's id explanation essentially restates the schema, adding no format, encoding, or validation guidance beyond it, so the 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 ('A chat visitor by id') and enumerates exactly what the response contains (basicInfo, integrationData, merged info, custom form answers, location, browser, dashboard link, agent group, latest-visit pages). The resource is unambiguously distinct from the message-oriented siblings and from chatra_update_visitor.

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?

Explains the required id's provenance (clientId from the widget or the visitor id from a Chatra webhook) and explicitly warns that 'Chatra has no endpoint to list or search visitors,' which steers the agent away from a lookup strategy it might otherwise attempt. It does not contrast with chatra_update_visitor or describe behavior when the id is unknown, so it falls short of a full when/when-not treatment.

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