slack_cancel_scheduled_messageCancel a scheduled Slack message before it sends by providing the channel ID and scheduled message ID.
Cancel a scheduled Slack message before it sends.
| Name | Required | Description | Default |
|---|---|---|---|
| channel_id | Yes | Channel ID the message was scheduled in | |
| scheduled_message_id | Yes | The scheduled_message_id returned by slack_send_message |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.4.0Input schema / properties / channel_id / descriptionAdded value: +"Channel ID the message was scheduled in"Input schema / properties / scheduled_message_id / descriptionAdded value: +"The scheduled_message_id returned by slack_send_message"v0.2.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It identifies the operation as a cancellation and the timing constraint, but does not disclose permission requirements, irreversibility, behavior if the message is already sent, or error conditions.
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 efficient sentence with no wasted words. The action and timing constraint are front-loaded and immediately useful.
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?
The tool is simple with two fully documented required parameters and an output schema, so basic completeness is met. However, as an unannotated mutation tool, the description should provide more behavioral context such as reversibility and permission expectations.
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 parameters are already well documented in the input schema. The description adds no additional parameter meaning beyond what the schema provides, which is acceptable given full schema coverage.
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 states a specific verb and resource: cancel a scheduled Slack message. It also adds the timing scope 'before it sends,' which distinguishes it from sending messages, though it does not explicitly name sibling alternatives.
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 phrase 'before it sends' implies the use case: cancel a scheduled message prior to delivery. However, the description does not state when not to use the tool, what to do if the message already sent, or name any related alternative tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.