send_email

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

Annotations already indicate this is a mutating operation (readOnlyHint=false, openWorldHint=true). The description confirms the action of sending but adds no additional behavioral context such as whether the send is synchronous, whether confirmation is returned, or any side effects beyond actually sending. With annotations covering the basic write nature, a score of 3 reflects minimal added transparency.

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?

One succinct sentence that front-loads the main action, then lists the key supporting features. Every word contributes to understanding, with no filler.

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 eight parameters and no output schema, the description is adequate to understand the tool's core purpose and key options. It doesn't cover return behavior or prerequisites beyond the schema, but for a straightforward send action with good schema coverage, it meets the minimum and is slightly better due to clear scope.

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 input schema has 100% parameter description coverage, so the baseline is 3. The description adds little beyond repeating that CC and BCC are supported and mentioning HTML body, but does not provide format details, syntax, or relationships beyond what the schema already documents.

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 the specific verb 'Send' and names the resource 'a new email', clearly distinguishing from siblings like reply_email, forward_email, and save_draft by emphasizing 'new'. It also mentions key format options (plain text/HTML, CC, BCC), making the purpose unambiguous.

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 implies usage for new outgoing emails by the phrase 'a new email', but it does not explicitly state when not to use it or name alternatives like reply_email, forward_email, or schedule_email. There is no when/when-not guidance, so it falls at implied usage.

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