send-mail

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

Annotations already indicate destructiveHint=true and openWorldHint=true. The description adds context about saving to Sent Items and warns against guessing email addresses, but does not elaborate on the full range of side effects or the irreversibility of sending.

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 relatively concise (6 sentences) and front-loads the main purpose. The tip is well-placed. Minor redundancy could be trimmed, but overall it is efficient.

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 (deeply nested schema, no output schema), the description lacks critical information such as expected response format, potential errors, or behavior on failure. It does not fully compensate for the absence of output schema.

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?

With 67% schema description coverage, the description provides only high-level guidance about JSON/MIME formats. It does not add significant meaning beyond what is already in the input schema for the body parameter and its nested properties.

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 'Send the message specified in the request body' and distinguishes between JSON and MIME formats. It mentions creating a draft as an alternative, which could cause slight confusion, but the primary purpose (sending mail) is unambiguous.

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 includes a critical tip to use list-users to find email addresses and contrasts sending vs. creating a draft. However, it does not explicitly specify when to use this tool over sibling tools like create-draft-email or send-draft-message.

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