Send Email

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

Annotations indicate readOnlyHint=false and destructiveHint=false, which the description does not contradict. It adds that the tool returns a messageId on success and mentions the transport mechanism (Proton Bridge), but does not disclose potential side effects like rate limits or authentication requirements beyond what is implied.

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 a single, well-structured sentence that front-loads the core purpose and then efficiently lists all key capabilities. Every clause adds value without 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 9 parameters, 3 required, and presence of an output schema (presumably defining messageId), the description adequately covers the essential context: SMTP transport, return value, and supported features. It is complete for an agent to understand the tool's behavior.

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?

Schema coverage is 100% with detailed parameter descriptions. The description adds minimal value beyond the schema, such as noting that addresses are comma-separated and attachments are base64-encoded, which are already in the schema. Baseline 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 clearly states the verb 'send' and the resource 'email', specifying it uses Proton Mail SMTP via Proton Bridge. It distinguishes from sibling tools like forward_email, reply_to_email, and send_test_email by listing unique capabilities (To/CC/BCC, base64 attachments, priority) not covered by those alternatives.

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 lists supported features but does not explicitly state when to use this tool versus alternatives. It implies usage for composing new emails but does not mention when not to use it or provide comparisons to siblings like forward_email or reply_to_email.

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