send_email

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

While no annotations are present, the description discloses the two-phase behavior (no SMTP on first call, send on second) and the allowlist restriction. It implies a write operation through 'SMTP-send' but does not explicitly mention side effects like email delivery or state changes, so a small gap remains.

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 description is concise, composed of two sentences that efficiently convey the tool's purpose, usage flow, and key constraints. No unnecessary words or redundancy.

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 (two-step flow, allowlist, recipient restriction), the description covers the essential context. It does not mention error handling, rate limits, or attachment behavior, but these are not critical for basic invocation and the tool has no output schema to explain, so it is reasonably complete.

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?

The description clarifies three of six parameters (to, account_id, confirm_token) with contextual details, but body and subject have no additional explanation. Since schema coverage is 50%, the description adds some value but leaves half the parameters underexplained.

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 the tool's dual-purpose: preparing a preview and sending a new message. It uses specific verbs 'Prepare' and 'SMTP-send' and distinguishes itself from sibling tools like send_draft or send_reply by focusing on new messages.

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?

It provides a clear two-step usage pattern: first call returns preview + confirm_token, second call sends with only confirm_token. Also mentions the allowlist requirement and warns against extracting recipients from email bodies, giving practical guidance.

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