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

No annotations are provided, so the description carries the full behavioral burden, and it does a lot: login required, permanence of the action, DM rejection with cannot_leave_dm, 404 meaning 'may already have left but not to be treated as success', and a no-retry warning. It stops short of describing the return payload or what leaving removes from the member list.

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?

Front-loads the login requirement and the permanence warning, and every clause carries information. The telegraphic style with arrows and tokens like 'DM400' is dense and slightly harder to parse than plain sentences, but nothing is wasted.

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 one-parameter mutation with no annotations and no output schema, the description covers auth, irreversibility, error-code semantics, and alternatives. Return-value behavior is not described, but that is a minor gap for this tool.

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 the baseline is 3, but the description adds real meaning by instructing the agent to confirm the group name (via list_my_conversations) before invoking, which tells the agent to validate the conversationId target rather than guess it.

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?

Uses a specific verb plus resource (permanently leave a GROUP conversation) and scopes it to groups, explicitly excluding DMs. An agent can distinguish it from set_conversation_muted without opening the schema.

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?

Explicitly names alternatives and the conditions that select them: use set_conversation_muted for quiet, set icebreak=false to stop future group pulls, and 'list_my_conversations→确认→退群' gives a concrete workflow. When-not guidance is also present (DM400 cannot_leave_dm, 勿重试).

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