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

Adds substantial behavior beyond annotations: login required, that a real chat/send occurs, no quota cap, and the subtle nuance that claiming is idempotent while the message is re-sent every call. It also maps error codes (400/404/409/429) to a no-retry rule, which is exactly the operational context an agent needs.

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?

Dense but well-structured with bracketed markers (login, chain) that front-load the critical auth constraint and purpose. Every clause carries information, though the density trades some readability.

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 mutating tool with annotations but no output schema, the description covers auth, side effects, idempotency nuance, error handling, and workflow position. Nothing needed to invoke it safely is missing.

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 needId and the optional ≤2000-char message are already documented in the schema. The description only restates the length cap and the 'confirm the target first' advice, adding marginal meaning beyond the structured fields, so 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?

States a specific verb and resource: contact the author of an active need and claim it, plus the concrete side effect of really starting a chat. It is clearly distinguishable from siblings like get_need (read) and complete_need (closing).

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 【组合链】 line gives an explicit call sequence (get_need → contact_need → get_conversation_needs/send_message → complete_need), telling the agent when this step belongs in a workflow. It does not spell out when NOT to contact (e.g. alternatives like start_conversation), so it stops short of full when/when-not guidance.

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