Send Mail Draft

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

There are no annotations, so the description must disclose behavioral traits. It does mention the permission requirement ('delegated Mail.Send'), but it does not describe what happens after sending (e.g., whether the draft is deleted, marked as sent, or if a response is returned). For a mutation tool, this is a moderate disclosure level.

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 concise sentence plus a useful bilingual intent list. Every part earns its place, and the core action is front-loaded. There is zero fluff.

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 simple one-parameter tool with no output schema and fully covered parameter schema, the description adequately covers purpose and permission. It could mention expected outcome or error behavior, but the simplicity of the operation makes this less critical. The Chinese intents also aid multilingual use.

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 description covers 100% of parameters (messageId with 'Draft message ID.'), so the baseline is 3. The tool description adds no extra detail about the parameter, such as how to obtain or format the messageId. Thus, it provides no added value beyond the schema.

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 uses a specific verb ('Send') with a clear resource ('an existing draft message'), which precisely identifies the tool's function and distinguishes it from siblings like mail_send (for new messages) and mail_create_draft (for creating drafts). The title 'Send Mail Draft' reinforces the purpose.

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 phrase 'existing draft message' clearly indicates the tool is for sending drafts, not composing new messages. It also states the required permission ('delegated Mail.Send'), which is a valuable prerequisite. However, it does not explicitly name alternatives or explain when not to use it, so it just misses a 5.

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