delete_msg

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

With no annotations, the description carries the full behavioral burden. It does disclose the key trait that this mutates state and erases the message ('会改变会话状态：消息会被抹掉'), which is genuine destructive-operation context. However it omits permission/auth requirements, irreversibility or failure behavior, and rate limits, so it is only partially complete.

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?

Two short sentences with zero padding; the action is stated first and the state-changing consequence second. Every clause earns its place.

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 destructive tool with no output schema and no annotations, the description covers the action and the destructive effect but says nothing about failure conditions, required permissions, or what the caller gets back. It is adequate but leaves meaningful gaps for a state-mutating operation.

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?

There is a single parameter and schema coverage is 100%, with the schema itself documenting the message_id and the two-minute eligibility window. The description adds no meaning beyond the schema, so the baseline 3 applies.

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 ('撤回一条已发出去的消息' / recall an already-sent message), which clearly separates it from the read-oriented get_msg sibling. It does not name any sibling or state how it differs from other 'set_' mutation tools, so it stops short of a 5.

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?

There is no when-to-use or when-not-to-use guidance, no mention of the two-minute recall window (that constraint lives only in the schema), and no routing to alternatives such as get_msg for reading or other message operations. The agent must infer usage entirely from the name.

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