update-draft

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

With no annotations provided, the description carries full burden. It covers omitted fields preservation, empty array clearing, refusal of attached drafts, and safety (updates only, sends nothing). This is comprehensive behavioral disclosure.

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 with sections 'Use when', 'Returns', 'Do not use when', and 'Safety'. Every sentence adds value, and it is front-loaded with critical usage guidance.

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 7 parameters, large sibling set, and presence of an output schema, the description covers all essential aspects: usage scope, parameter behavior, return value, and safety. Error handling is omitted but acceptable for typical use.

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 low (14%), so description must compensate. It explains that omitted fields are preserved, empty arrays clear recipients, and from can be identity id/email/sender. However, it does not detail subject or body beyond their existence, leaving some gap.

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 it edits an existing Apple Mail draft, selected by draft_id. It distinguishes from sibling create-draft and from editing drafts with attachments, providing a specific verb+resource+scope.

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?

Explicitly provides 'Use when' and 'Do not use when' scenarios, with alternatives like create-draft and editing drafts with attachments in Mail.app. The description gives clear context for when to invoke this tool vs siblings.

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