send-email

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

The annotations include 'destructiveHint: true', indicating this is a write operation with potential side effects. The description adds that it uses 'Mailtrap Email API' and supports multiple recipients, providing some context beyond annotations. However, it doesn't disclose additional behavioral traits like rate limits, authentication needs, or what 'destructive' entails (e.g., email delivery, no undo). With annotations covering the safety profile, a 3 is appropriate for adding moderate value.

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 with two sentences: one stating the purpose and one adding a usage detail. It's front-loaded with the core functionality. However, the second sentence could be more informative (e.g., clarifying 'multiple recipients' vs. schema details), slightly reducing efficiency.

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 (8 parameters, destructive operation) and lack of output schema, the description is moderately complete. It covers the basic purpose and API context but lacks details on when to use, behavioral nuances, or return values. With annotations providing some safety info, it's adequate but has clear gaps for a mutation 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?

The input schema has 100% description coverage, with clear documentation for all 8 parameters (e.g., 'from' as 'Email address of the sender'). The description doesn't add meaning beyond the schema, such as explaining parameter interactions or constraints. According to the rules, with high schema coverage (>80%), the baseline is 3 even without param info in the 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?

The description clearly states the tool's purpose: 'Send an email to your recipient email address using Mailtrap Email API.' It specifies the action (send), resource (email), and technology (Mailtrap Email API). However, it doesn't explicitly differentiate from sibling tools like 'send-sandbox-email' or 'get-sandbox-messages', which would require a 5.

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 provides minimal usage guidance: 'You can send emails to multiple recipients at once.' It doesn't specify when to use this tool versus alternatives like 'send-sandbox-email' (e.g., for testing vs. production), nor does it mention prerequisites, exclusions, or context for use. This lack of explicit guidance limits its effectiveness.

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