list_message_chats

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

No annotations are provided, so the description carries the burden. It discloses the output fields (chat id, name, service) and the read-only nature of 'Lists', but it does not mention potential limitations like how 'recent' is defined or whether permissions are required. The description adds some transparency beyond the tool name.

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 a single concise sentence that immediately states the action and scope, with the output fields in parentheses. No redundant words or 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?

Given the tool has zero parameters and no output schema, the description adequately covers its purpose and return values. It lists the key fields, and while it could mention 'recent' interpretation, the simplicity of the tool makes this sufficient.

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?

The tool has no parameters, and the schema is empty, so the baseline is 4 per the rubric. There is no parameter information needed, and the description does not need to compensate for any missing details.

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 clearly states the tool lists recent iMessage/Messages.app conversations and specifies the output fields (chat id, name, service). This distinctly identifies it from sibling tools for other messaging platforms like whatsapp_list_chats or signal_list_chats.

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 description implies use for accessing iMessage conversations but does not explicitly mention when to use it over alternatives like WhatsApp or Signal chat lists. There are no direct exclusions or guidance, but the iMessage-specific phrasing provides clear context.

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