compose_email

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

With no annotations provided, the description carries the full burden of disclosing behavior. It reveals key behavioral traits: 'opens the compose window with a draft' by default and 'sends immediately without confirmation' when send=true. This goes beyond the schema by noting the lack of confirmation, which is critical for the agent.

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?

Two sentences, front-loaded with the core purpose, and every word earns its place. No redundancy or irrelevant details.

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?

The tool is relatively simple with 5 parameters and no output schema, and the description sufficiently explains the primary behavior. It covers the draft vs send distinction but could optionally mention error handling or response details, though these are not essential.

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 input schema already covers 100% of parameters with descriptions, so baseline is 3. The description adds nuance about the send parameter ('without confirmation') and reinforces the default draft behavior, providing marginal 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 clearly states 'Compose a new email' with a specific verb and resource, and explains the two modes of operation (draft vs send). It effectively distinguishes this tool from siblings like reply_email or draft_reply by focusing on composing a new email.

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 provides clear context for when to use send=false (draft) vs send=true (immediate send), which is essential for correct usage. However, it does not explicitly compare against sibling tools or state when not to use this tool.

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