send_message

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

No annotations are provided, so the description carries the burden. It discloses the SMTP environment dependency and the text/html constraint, but does not mention return values, error behavior, or side effects like sending delays or recipient validation.

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 is a single sentence that front-loads the primary action ('通过 SMTP 发送邮件') and then provides necessary constraints. It is concise with no unnecessary words.

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 7 parameters and no output schema, the description provides essential operational context (SMTP env var, body condition) that complements the schema. It lacks explicit return/error information, but for a send tool this is a minor gap.

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 schema covers 100% of parameters, so baseline is 3. The description adds the crucial constraint 'text 与 html 至少填一项' (at least one of text/html required), which is not captured in the schema and clarifies parameter usage.

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 '通过 SMTP 发送邮件' (send email via SMTP) clearly identifies the action (send) and resource (email), with a specific mechanism (SMTP). This distinguishes it from sibling tools focused on listing or searching messages.

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 context such as using the SMTP environment variable and the requirement that at least one of text/html must be filled. It doesn't explicitly name alternatives, but the purpose is distinct enough from siblings to imply when to use it.

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