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

The description discloses the key behavioral trait by stating that it actually sends the email, going beyond the annotations (readOnlyHint=false, destructiveHint=false). It does not mention potential side effects like email delivery failure or permissions, but the main side effect is clearly communicated. No contradiction with annotations.

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 and well-structured: three sentences that cover purpose, a constraint, and the side-effect distinction. No fluff or repetition; it gets straight to the point and is easy to scan.

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 simple action with no output schema, the description covers the core aspects: what it does, that it actually sends the email, and what alternatives exist. It does not mention error cases or what happens if no email is on file, but given the simplicity, the description 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 schema descriptions already provide clear explanations for both parameters (id and email), and the tool description does not add significant meaning beyond them. With 100% schema coverage, the baseline is 3, and there is little extra semantic value added by 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 action: it emails a document to its contact. It specifies the resource (document) and the verb (send/email), and explicitly distinguishes it from related actions like marking as sent or logging a payment, so an agent can easily understand its purpose.

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 tells when to use this tool: 'This actually sends the email' and contrasts it with mark_document_sent and record_document_payment, providing clear guidance on when to choose this over alternatives.

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