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

Annotations already cover safety (readOnlyHint=true, openWorldHint=true), so the description's added value is the disclosure of what comes back — full contact data, notes, UTM data, browser/OS and custom fields — which is useful given no output schema exists. It omits any note about the error/not-found behavior or whether the response is a single flat object.

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 short sentences, front-loaded with the action and followed by the returned payload and the underlying endpoint. No filler.

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 one trivially documented parameter and no output schema, the description does the needed work by enumerating the returned fields. Only minor gaps remain (not-found behavior, response shape), which is acceptable for a simple read tool with readOnlyHint declared.

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% and the single parameter is already documented with its provenance ("from chaport_list_visitors"), so the baseline is 3. The description's "by id" adds nothing beyond the schema.

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 visitor by id") and enumerates the data returned (contact data, notes, UTM, browser/OS, custom fields), which clearly separates it from list-style siblings. It never names the sibling to prefer for bulk retrieval, so differentiation is implied 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 phrase "by id" plus the schema note pointing at chaport_list_visitors implies the workflow (list first, then fetch one), but the description itself gives no explicit when-to-use or when-not guidance and does not mention chaport_get_last_visitor_chat as the alternative for the most recent visitor's chat.

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