imap_send_email

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

With no annotations provided, the description carries the full behavioral burden. It discloses important side effects: a copy is saved to Sent unless disabled, account defaultBcc addresses are always BCC'd, and attachments can be provided by base64 or file path. It doesn't mention failure behavior or auth requirements, but the disclosed behaviors go well beyond a bare 'send email' statement.

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 front-loaded sentences: the first states the action and key side effects, the second routes to alternatives, the third covers capabilities. Every sentence earns its place and the most important scoping information comes first.

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?

For a complex mutation tool with 11 parameters and no output schema, this description covers purpose, side effects, alternatives, and attachment options. It doesn't explain what happens on failure or whether an active connection is required, but those are minor given the detailed input schema and strong routing guidance.

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 100%, so the baseline is 3. The description adds value beyond the schema by clarifying that attachments can use base64 or file path and pointing to imap_upload_file for large files, plus noting defaultBcc merging with the bcc parameter. This is useful semantic guidance above what the schema properties already state.

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 clearly states 'Compose and send a NEW email' with a specific resource (SMTP server) and explicitly distinguishes from siblings by naming imap_reply_to_email, imap_forward_email, and imap_save_draft. The verb+resource+scope is unambiguous and differentiates this tool from the many sibling email operations.

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 explicitly says 'Use for fresh outbound messages' and then gives conditional alternatives: respond uses imap_reply_to_email, forward uses imap_forward_email, and store without sending uses imap_save_draft. This is exactly the kind of when-to-use vs. alternative guidance an agent needs.

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