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

Adds substantial behavior beyond the annotations: partial-update semantics, the null-clears-a-language rule, a per-user prerequisite for three fields, and the side-effect statement 'This sends nothing to the customer,' which is the key consumer-facing consequence for a call flagged destructiveHint=true. This is exactly the context 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?

Five short sentences, front-loaded with the action and then the rules, with no filler. The phrase 'the same ones the chat language panel sets' is a vague reference for an API consumer and is the one soft spot.

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?

An output schema exists, so return values need not be described, and the mutation semantics, null behavior and auth prerequisite are covered. What remains missing is any meaning for the three undocumented settings fields and a pointer to the read sibling for inspecting current state.

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 0% and the settings object is nested with six undocumented properties, so the description carries the burden. It explains null-clearing and the ownership/prerequisite of translate_outgoing_to, record_voice_in and send_voice_in, but leaves auto_transcribe, transcription_language and translate_incoming_to undefined, so it only half compensates.

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 and scope: 'Change one chat's language and voice settings.' The word 'Change' clearly separates it from the read counterpart get_chat_language_settings, and 'Org-wide defaults stay in Settings' delimits it against org-level configuration.

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?

Gives clear usage context: partial updates ('Only the fields you pass change'), a prerequisite ('need a connected account') for three specific fields, and an exclusion (org-wide defaults live in Settings). It does not explicitly name get_chat_language_settings as the tool for reading current values, leaving that inference to the agent.

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