send_new_email

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

With no annotations, the description carries full burden. It discloses immediate sending behavior, return details (message ID and thread details or error). Lacks authentication or rate limit info, but sufficient for common email sending.

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?

Concise opening, followed by a behavioral note, then structured args list, ending with returns. No extraneous text. Could be slightly more compact, but well-organized.

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?

Covers purpose, parameters, and return for a 6-param tool with no output schema. Does not explain error details in depth, but 'error information' suffices. No mention of attachments or throttling, but reasonable for the complexity.

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 has 0% description coverage, so description adds significant value: explains comma-separated for multiple recipients, default values, and body_type options ('plain'/'html'). All parameters are meaningfully explained.

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?

Description clearly states 'Send an email directly via Gmail' and distinguishes from sibling tools by noting it sends immediately without creating a draft first. The verb 'send' and resource 'email' are specific.

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?

Description explicitly says 'without creating a draft first', contrasting with draft-related siblings. However, it does not provide explicit when-not-to-use guidance or list alternatives beyond the draft distinction.

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