Send email

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

No annotations are provided, so the description must cover behavioral traits. It only says 'Send an email NOW' implying immediate action, but does not disclose potential side effects (e.g., irreversibility), authentication requirements, rate limits, or what happens on success/failure. More transparency is needed for a tool that performs a real-world action.

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?

Two sentences, front-loaded with the action and a clear usage condition. No filler or redundancy. However, it could include more useful details without becoming overly verbose.

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 tool's complexity (9 parameters, no output schema, no annotations), the description is insufficient. It lacks details on return values, constraints (e.g., attachment limits), error handling, or post-send behavior. The context signals indicate high complexity, but the description does not address it.

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 44%. The description adds no parameter-level information beyond the schema, which already describes some parameters (to, text, html, attachments' path and contentBase64, inReplyTo). Undocumented parameters like cc, bcc, subject, and attachment properties remain unclear. The description should compensate for schema gaps but does not.

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 explicitly states 'Send an email NOW,' which is a clear verb+resource. It distinguishes from sibling tools like compose_preview, save_draft, reply, and forward that deal with email composition or other actions.

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 provides explicit guidance: 'Only call after the user has explicitly approved sending (ideally after a compose_preview).' This tells when to use and suggests a prerequisite (compose_preview). However, it does not mention when not to use or alternative tools for other email actions.

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