send_email

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

No annotations are provided, so the description carries the full burden. It discloses supported content types and recipient options, which adds useful context. However, it does not mention prerequisites like SMTP authentication, side effects, or what happens after sending.

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 two sentences, front-loading the primary action and listing key capabilities without redundancy. Every sentence earns its place, and the structure is clean and direct.

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 schema thoroughly documents parameters, and the description covers the main purpose and supported features. Since there is no output schema, the description does not clarify return values or error behavior, but this is a minor gap for a straightforward send operation.

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 input schema has 100% parameter coverage with descriptions for all 8 parameters. The description adds no additional meaning beyond what the schema already provides, so the baseline score of 3 is appropriate.

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 uses a specific verb ('Send') and a clear resource ('email via SMTP'), making the tool's function immediately obvious. It also lists key features (HTML, plain text, attachments, CC/BCC) that distinguish it from sibling tools like fetch_emails or test_smtp_config.

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 does not explicitly state when to use this tool vs alternatives, nor does it mention exclusions. The intended usage is implied by the verb 'Send', but there is no guidance to help the agent choose it over other email-related tools.

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