send-mail

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

Annotations indicate destructiveHint=true, and description mentions MIME saves to Sent Items. No annotation contradiction. However, description lacks details on rate limits, authentication, or immediate delivery 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?

Description is two paragraphs plus a tip. It is mostly clear but could be slightly more concise. The important tip is well highlighted.

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?

No output schema provided, and description does not explain what the tool returns (e.g., sent message object). Lacks details on error cases and response format for a complex mutable action.

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 75%, so the schema already documents most parameters. Description adds little beyond the tip about email addresses. Baseline score 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?

Clearly states the tool sends a message, can use JSON or MIME format, and mentions attachment capability. Distinguishes itself from creating a draft by offering that alternative.

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?

Provides guidance on JSON vs MIME usage (attachments vs saving to Sent Items) and gives a critical tip to use list-users for recipient addresses. However, it does not explicitly differentiate from other send-related sibling tools like send-draft-message.

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