slack_cancel_scheduled_message

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

With no annotations, the description carries the burden; it does disclose the core behavior, the timing constraint ('before it sends'), and the confirmation-shaped return. However, it does not mention permissions/scope requirements, error behavior for already-sent messages, or whether cancellation is irreversible.

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 compact and front-loaded with the one-sentence purpose, followed by a clear Args/Returns structure. Every line adds information 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 two-parameter cancellation tool, the description covers the core invocation details, lifecycle origin, and return value; an output schema exists to fill in return structure. It leaves out only edge-case behavior such as already-sent messages or required Slack scopes, which keeps it from a 5.

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 0%, so the description must compensate, and it does: it identifies channel_id as the channel where the message was scheduled and explains that scheduled_message_id comes from slack_send_message. This is meaningful guidance beyond the bare string names in the 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 opens with a specific verb and resource: 'Cancel a scheduled Slack message before it sends.' It clearly identifies the tool as the cancellation counterpart to slack_send_message and is not confusable with any sibling tool.

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 gives clear context: use this to cancel a scheduled message before it sends, and it anchors the scheduled_message_id to a value 'returned by slack_send_message.' It does not explicitly list when-not-to-use alternatives, but no true alternative exists among the siblings.

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