gmail_send_message

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

Annotations already indicate destructive/read-only status, and the description adds the key consequence: it reaches people immediately and cannot be undone. It also frames the safer alternative workflow, adding context beyond structured data.

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 warning and usage guidance are front-loaded, and the parameter block is compact and readable. Every sentence earns its place 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 the simple parameter set, output schema, and annotations, the description covers purpose, when to use it, side effects, and all parameters. No critical information needed for correct invocation is missing.

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 description coverage is 0%, so the description must compensate. It does by explaining comma-separated recipients, plain-text body, and cc/bcc roles. It could include address format details, but the coverage is solid for this API.

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?

States a specific verb-resource pair ('Compose and send') and clearly marks this as the immediate-send tool. The opening line distinguishes it from the draft/send-draft siblings.

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?

Explicitly directs the agent to prefer gmail_create_draft followed by gmail_send_draft once text is approved, and says 'Use this only when told to send outright.' This is strong positive and negative routing.

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