send_test_email

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

Discloses side effect: 'sends a real email.' Adds context beyond annotations: tests not counted against limits and not tracked. This is critical behavioral information not captured in structured fields.

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?

Concise and well-structured: first sentence states purpose, then notes side effect, then lists parameters with examples. No redundant information; every sentence adds value.

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?

With an output schema present, the description explains the return format and error case. 3 of 4 parameters are explained (account missing). Differentiates well from siblings. Adequate for a test/preview tool.

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?

Despite schema coverage of 0%, the description provides detailed explanations for campaign_id (example, prerequisite), test_emails (comma-separated, max 10), and send_type (default html, plaintext). The account parameter is not explained, slightly reducing completeness.

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?

Clearly states the tool sends a test/preview email to specific addresses without affecting the real audience. The verb 'send' and resource 'test/preview email' are specific, and it distinguishes from siblings like send_campaign by emphasizing it does not affect the real audience.

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?

Provides explicit guidance: 'Recommended before send_campaign or schedule_campaign' and prerequisite 'Campaign must have content set via set_campaign_content.' Also notes tests do not count against send limits and are not tracked in reports, but does not explicitly state when not to use.

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