send_email

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

No annotations are provided, so the burden falls entirely on the description. 'Send an email' discloses no behavioral traits: no mention of side effects (e.g., saving to Sent folder), authentication requirements, rate limits, or error behavior. The description merely repeats the tool name without adding any contextual detail.

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 sentence with no waste, but it is under-specified. While it earns its place by stating the core action, it provides no additional useful information. It is neither verbose nor helpfully detailed, placing it at the minimum viable level.

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?

With 12 parameters, no output schema, and no annotations, the description is far too minimal. It fails to explain what happens after sending, how to handle attachments (despite schema details), whether it is immediate, or expected return behavior. The lack of context makes it difficult for an agent to anticipate consequences, so it is incomplete.

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 provides 100% coverage of the 12 parameters with clear descriptions, including details like the 'attachments' object's EXACTLY ONE source constraint. Since the description adds no parameter information itself, the baseline of 3 applies. The schema carries the full semantic weight, so the description's lack of parameter detail is not a significant penalty.

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 'Send an email' clearly states the action (send) and resource (email), making the core purpose unambiguous. However, it does not differentiate from sibling tools like send_draft or reply_email, which are both send-like operations. Still, the basic purpose is clear.

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?

There is no guidance on when to use this tool versus alternatives such as reply_email, send_draft, or create_draft. The description provides no context for distinguishing between direct sending and other email operations, leaving the agent to infer usage from the tool name.

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