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

Annotations declare destructive and open-world, and the description goes further: it explains that the draft is sent exactly as stored including in-app edits, that the draft is removed from Drafts, that recipients are external, and that there is a few-minute hold cancellable from notifications or Outbox. That is real behavioral context an agent cannot get from the annotations alone.

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?

Three sentences, front-loaded with the action and the side effect (removal from Drafts). Every sentence carries information, though the opening sentence is long and packs the send semantics and the deletion together.

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?

For a non-idempotent, destructive send with an output schema, the description covers what is sent, who receives it, what is destroyed, and the cancellation window. Nothing an agent needs before calling is missing.

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 description coverage is 100%, so both draft_id and scheduled_for are already documented, including the rule that an earlier time is pushed to the end of the hold. The description adds nothing parameter-specific beyond that baseline, which is acceptable but not additive.

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?

States a specific verb and resource: sends the current user's saved draft verbatim and removes it from Drafts. That is unambiguous and clearly distinct from the draft-creation/update tools. It stops short of explicitly contrasting with the sibling send-email-tool, which also dispatches mail, so sibling differentiation is inferred rather than stated.

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?

Gives a clear precondition ('only when the user asked for it') because the email reaches people outside the workspace, which is exactly the kind of gating an agent needs. It also flags that the send is cancelable during a hold, implying an alternative path, though it never names cancel-email-tool or reschedule-email-tool as the tools to reach for.

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