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

The annotations already declare idempotentHint, destructiveHint, and openWorldHint, so the safety profile is partly covered structurally. The description adds valuable behavior beyond annotations: only supplied fields change, the updated visitor is returned, and the operation maps to PUT /visitors/{visitorId}.

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?

The description is three short sentences, front-loaded with the action and affected fields. Every sentence contributes either scope, update semantics, return behavior, or endpoint context.

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 mutation tool with nested utm/custom objects, one required ID, full schema coverage, and annotations covering idempotency and destructive behavior, the description is nearly complete. It could say more about permissions, side effects, or prerequisites, but nothing critical for invocation 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 description coverage is 100%, so the baseline would be 3, but the description adds meaningful semantics about partial updates: 'Only the fields you pass change.' That clarifies how all optional parameters behave in a way the schema alone does not.

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?

The description states a specific verb and resource ('Update a visitor'), then enumerates the contact fields affected. This clearly distinguishes it from sibling read tools such as chaport_get_visitor and chaport_list_visitors.

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 implied by the purpose: use this to change an existing visitor's contact data. However, it gives no explicit when-to-use guidance, prerequisites, or comparison to alternatives, and does not state when not to use it.

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