send_email

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

Adds rich behavior beyond annotations: the elicitation/preview flow, the confirmation_token requirement, and the rule that any change to recipients/subject/body/attachments causes rejection. This tells the agent exactly how the destructive send is gated, which annotations alone do not convey.

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?

Three tightly packed sentences, front-loaded with purpose then the two-phase protocol. No filler; each clause conveys actionable constraint.

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?

The critical send-safety workflow is complete, but with 16 params, no output schema, and a sparse preview description ("full preview" unexplained), the definition leaves gaps around the reply/forward parameter family and what the preview response contains.

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?

With 16 parameters at 38% schema coverage, the description should carry the load, but it only says "same arguments as create_draft." It never clarifies reply_to_id/reply_all, forward_id/forward_mode, quote_original, or delete_draft_after_send, leaving the majority of params undocumented in both schema and description.

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 ("Send an email via SMTP") and immediately distinguishes the two modes (compose with create_draft's arguments, or draft_id). It also names the sibling create_draft, so an agent can route correctly.

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 explains the two-phase call protocol: first call returns a preview/elicitation, second call uses confirmation_token only after explicit user approval. It lacks a crisp "use create_draft instead when you only want to save," but the reference to create_draft and the approval flow give strong usage context.

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