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

Annotations already declare destructiveHint=true and idempotentHint=true, so the description's real contribution is the partial-update contract: only passed fields change and `null` removes a value, plus that the updated visitor is returned. That meaningfully clarifies the destructive behavior declared in annotations, though it says nothing about auth or failure modes.

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 compact sentences, front-loaded with the WRITE marker, then the semantics, then the return/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?

Complete enough for a partial-update mutation: return value is noted despite no output schema, and annotations carry the safety profile. Missing only edge-case behavior (unknown client_id, validation failures), which keeps it off a 5.

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 baseline is 3; the description earns a bump by stating the cross-parameter rule that only supplied fields are modified and `null` clears them, which the per-field schema descriptions imply but never state as a contract.

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 ('WRITE: edit a visitor's basic info') and enumerates the editable fields, so it is immediately distinguishable from the sibling message tools (chatra_edit_message, chatra_send_message) and from the read-only chatra_get_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?

The 'WRITE:' prefix and 'as if an agent edited it in the Chatra dashboard' framing imply this is the mutation path for visitor data, but there is no explicit 'use chatra_get_visitor to read first' or any when-not guidance. Usage is inferable rather than stated.

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