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 for behavioral disclosure. It only describes parameters and does not mention side effects, authentication requirements, rate limits, or what happens on success/failure. For a tool that sends data, this is a significant gap.

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 front-loaded with a one-sentence summary, followed by a structured parameter list. While it is relatively long due to detailed parameter docs, the structure is clear and each sentence serves a purpose. A minor improvement would be to shorten the attachment explanation, but it's still efficient for a complex tool.

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 (7 parameters, attachments, optional fields), the description covers parameter semantics well. It does not explain return values, but an output schema exists (not shown) which likely handles that. However, it lacks behavioral context like error handling or size limits, which would help an agent fully understand invocation risks. Overall, it is sufficient for basic selection and invocation.

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 coverage is 0%, meaning the schema itself lacks descriptions for top-level parameters. The description compensates thoroughly by explaining each parameter (account, to, subject, body, cc, reply_to, attachments) and the attachment object structure, including required fields and defaults. This adds substantial value beyond the schema.

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 starts with 'Send an email with optional attachments,' which clearly states the verb (send) and resource (email). It distinguishes itself from sibling tools like delete_email, get_email, and list_accounts by focusing on sending rather than retrieving or deleting.

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, such as not to use it for reading emails or when to prefer list_emails. It provides no when-not-to-use guidance, leaving the agent to infer from sibling names. This is adequate but not proactive.

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