create_rich_email_draft

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

With no annotations, the description reveals key behaviors: it generates an unsent .eml file, can open in Mail, can save as draft, and provides fallback body generation. It also describes the return value structure. It lacks details on permissions or error conditions but is fairly thorough.

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 well-structured: a brief summary, a rationale paragraph, and a clean Args list. Every sentence adds value, and it is not verbose.

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 complexity (10 params, 1 required, no annotations, output schema exists), the description covers all parameters, behavioral details, return values, and usage context comprehensively.

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 0%, but the description explains all 10 parameters in the Args section, including defaults, formats (comma-separated), and fallback logic for body parameters. This adds substantial meaning beyond the bare 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 the verb 'create', the resource 'rich-text email draft', and the mechanism 'generating an unsent .eml message'. It distinguishes itself from siblings by being the preferred path for HTML/rich formatting versus other tools like compose_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?

It provides explicit context: 'This is the preferred path for HTML or richly formatted emails because Mail reliably renders .eml content, while setting raw HTML through AppleScript often stores the literal markup instead.' This tells when to use and hints at when not to use, though does not name the alternative tool explicitly.

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