Edit a pending send

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

Annotations already cover idempotency and lack of destructiveness; the description adds useful behavioral context by noting that the reviewer sees the edited version and that the message still requires approval afterward. This gives an agent a clearer picture of the edit's real-world effect beyond just a generic mutation.

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 short sentences, each earning its place: the first names the action, the second explains the post-edit workflow, and the third constrains the subject parameter. The most important information is front-loaded, and there is no filler.

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 small update tool, the description plus full schema coverage gives an agent enough to invoke it correctly: what can be changed, the required approval_id, and the continuing approval requirement. A minor gap is that it does not describe the outcome if the approval is no longer pending, but this is not essential for a correct call.

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 already describes all four parameters at 100% coverage, so the baseline applies. The description adds a meaningful nuance beyond the schema by explaining that 'subject' only applies to operations carrying one (email_send, schedule_create), which is directly relevant to when an agent should pass that parameter.

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 ('Change') and resource ('a send that is waiting for human approval'), and clearly identifies the editable fields (subject or body). It also clarifies the scope of subject editing by naming which operations carry one, which helps distinguish this from approval_decide and approval_review.

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 clearly indicates this is for pending sends still awaiting approval, and notes that approval must still happen afterwards, implicitly steering agents away from using this as a final decision tool. It does not explicitly list alternatives or say 'do not use for approved sends,' but the context is strong enough for correct routing among siblings.

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