ghl_cancel_scheduled_message

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the action ('Cancel') but does not mention whether cancellation is irreversible, any side effects, permission requirements, or what happens to the message after cancellation. This is a significant gap for a mutating operation.

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 a single, concise sentence with no redundant words: 'Cancel a scheduled (future) message before it is sent.' Every word contributes to the meaning.

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 simple one-parameter cancel operation, the description conveys the core purpose adequately. However, the absence of annotations and any explanation of outcomes, error conditions, or idempotency leaves some gaps, though these are less critical given the tool's simplicity. It is minimally viable but not rich.

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 has 100% coverage, with the messageId parameter described as 'ID of the scheduled message to cancel.' The description adds no new semantic meaning beyond what the schema already provides, so the baseline of 3 applies.

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 uses the specific verb 'Cancel' with a clear resource: 'a scheduled (future) message before it is sent.' This distinguishes it from sibling tools like send_message or update_message_status by explicitly scoping to future scheduled messages.

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 that this is only for scheduled messages not yet sent ('before it is sent'), which effectively excludes already-sent messages. It does not explicitly name alternatives, but the context is clear enough for basic usage decisions.

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