wechat_send_files

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. It discloses only the 1GB per-file limit — which is already repeated in the schema's files parameter — and says nothing about prerequisites (WeChat must be running/logged in), failure behavior, rate limits around the delay parameter, or whether sending is retried. For a write/action tool with zero annotation coverage this is a significant gap.

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 front-loaded sentence stating the verb, scope, and constraint with no filler. It is not under-padded to the point of being cryptic, but it also omits any routing or prerequisite information that would have earned space.

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?

An output schema exists, so return values need not be described, and the schema fully documents all 5 parameters. However, for an unannotated mutation tool, the description omits prerequisites, failure modes, and any hint about file-type or path validity, leaving gaps an agent would want before invoking it.

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%, so every parameter (files, to_user, messages, messages_first, delay) is already documented in the schema, setting the baseline at 3. The description adds no format or syntax detail beyond what the schema provides; the 1GB note duplicates the files parameter description.

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 (发送) and resource (本地文件) plus the recipient scope (单个好友或群聊) and a key constraint（单个文件需小于 1GB）。An agent can distinguish it from wechat_send_message and wechat_send_multiple_messages, though no sibling is named explicitly.

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 recipient scope (single friend or group chat, as opposed to multiple friends) implicitly signals when this tool applies, but there is no explicit when-to-use, when-not, or named alternative such as wechat_send_message for text-only sending.

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