wechat_export_chat_files

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

With no annotations, the description carries the full behavioral burden. It usefully discloses one failure mode (expired/undownloaded files cannot be exported), which is real value beyond the schema, but it says nothing about local write behavior, permissions, or whether an export is idempotent. Output schema exists, so return values need not be covered.

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?

A single compact sentence with the core action front-loaded and the caveat placed in a parenthetical at the end. Nothing is wasted, though the brevity leaves room for a routing hint at no real cost.

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 three-parameter file-export tool with full schema coverage and an output schema, the description covers the essential action and one important constraint. It omits sibling differentiation and any note on the side effect of writing files to disk, which leaves gaps an agent must resolve elsewhere.

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 description coverage is 100% and all three parameters (number, to_user, target_folder) are documented inline with defaults and exact-match semantics for to_user. The description adds no parameter-level detail beyond the schema, so the baseline of 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 (导出/export) and resource (聊天文件/chat files) plus the destination (本地目录/local directory), which clearly separates it from sibling readers like wechat_get_chat_history. It does not explicitly name a sibling, but the verb+resource combination is unambiguous.

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?

Usage is implied by the verb and the friend-scoped framing, and the parenthetical adds a failure condition (expired/undownloaded files cannot be exported). However, it never states when to prefer this over wechat_get_chat_history or wechat_send_files, so the agent must infer the routing.

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