get_recent_sessions

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

No annotations are provided, so the description carries the burden of behavioral disclosure. It adds value by stating the output fields (message summary, unread count, time) and implies recency via '最近', but it does not mention sorting order, filtering, auth requirements, or pagination behavior. The verb 'get' implies read-only, but this is not explicitly stated.

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 consists of two short sentences that are front-loaded with the main action and then provide usage context. There is no filler or redundant information, making it highly concise and well-structured.

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's simplicity (one optional parameter, no annotations) and the existence of an output schema, the description adequately covers the tool's purpose and output content. It does not delve into edge cases or operational prerequisites, but for a simple read-only list tool, this is acceptable.

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 input schema covers the single 'limit' parameter with a clear description and default value (20), achieving 100% schema description coverage. The tool description does not mention this parameter at all, so it adds no additional meaning beyond the schema, which is the baseline for high coverage.

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 '获取微信最近会话列表' (get WeChat recent session list), specifying the verb and resource. It distinguishes itself from siblings like get_chat_history and search_messages by focusing on sessions rather than messages, and mentions the included fields (latest message summary, unread count, time).

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 provides a clear context for use: '用于了解最近有哪些人/群在聊天' (used to understand who/groups have been chatting recently). While this implies the appropriate scenario, it does not explicitly mention alternatives or exclusions, such as when to use search_messages instead.

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