Send Email

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

With no annotations, the description carries the full burden. It usefully discloses the fixed sender identity and the HTML rendering restrictions (tags that survive vs. those stripped), which is genuine behavioral context. However, for a tool that fires irreversible outbound email, it says nothing about required permissions, rate limits, or delivery failure behavior.

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 purpose and sender constraint are correctly front-loaded, but roughly 80% of the text is an HTML compatibility list that is repeated word-for-word in the schema's content field. The repetition bloats the definition without adding new information.

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 and all four parameters are fully documented, so the agent has what it needs to construct a call. The main gap is behavioral rather than structural: nothing covers failure modes, throttling, or whether the send is authenticated as the app identity.

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%, and the HTML guidance in the description is duplicated almost verbatim in the content parameter's own description, so the prose adds no meaning beyond the schema. Baseline 3 is correct when the schema does the heavy lifting.

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 ('通过企业微信官方邮件 API 发送普通邮件') and adds a real scoping fact: the sender is fixed to the current app mailbox account. It does not explicitly differentiate from the only sibling, get_mailbox_info, but that sibling is a read tool on a different resource, so confusion risk is low.

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 explicit when-to-use/when-not-to-use or alternative routing, though as the sole send tool the implied usage is clear. The conditional guidance it does give is parameter-level (pass content_type=html for HTML bodies), not tool-selection guidance.

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