Cancel workflow `flow.cancel`

A cancel node finishes a run that already has a durable cancellation request. It has no settings and is not a general control-flow exit. The host first records the request and reason. Workflow code can then release locks, withdraw external tasks, notify child runs, or perform compensation before entering this node to commit the cancelled outcome.

Cleanup order

Cleanup may require several durable steps after the request arrives. Give each operation separate stable node identity and make it safe for repeated delivery. When an external resource cannot be released, choose an explicit retry, recorded failure, or human-repair path instead of silently skipping critical work. A parent also waits while managed child workflows finish their cancellation cleanup.

The node accepts only in control and has no data or outgoing ports. The cancellation reason comes from the original request rather than node configuration. The engine rejects this outcome if no request is present. A business action called cancel, reject, or close therefore needs a clear semantic choice. If it is an ordinary business result, express it with a condition followed by complete or fail.

Race and recovery tests

Test task completion racing with cancellation, hook receipt racing with cancellation, child-run cancellation, cleanup retries, repeated requests, and process recovery. History must contain exactly one terminal outcome. A control plane should report whether cancellation was accepted, cleanup is still running, or the run is already cancelled, and it should retain the original reason and request identity for operators.

Use it to finish a run that already has a durable cancellation request. Workflow code normally releases resources or waits for child cleanup before reaching this node.

Runtime behavior

The node has no settings. The engine rejects it without a cancellation request, and the committed outcome keeps the reason from that request.

Node contract

Type: flow.cancel
Role: Durable runtime command
Runtime binding: cancel
Durable identity: Defined by graph structure

Configuration properties

This node has no configurable properties. Its behavior depends entirely on run state when control reaches it.

Ports

Direction	Port ID	Kind	Value types
Input	`in`In	control	`FlowControl`

Node JSON example

The CLI creates the same structure from manifest defaults. Canvas position, title, and selection are presentation data.

workflow.json

{
  "position": {
    "x": 320,
    "y": 160
  },
  "id": "example-flow-cancel",
  "data": {
    "type": "flow.cancel"
  }
}

CLI usage

Inspect the installed manifest first, then create the node and validate the complete workflow. Every command emits JSON.

Terminal

a3s-flow node flow.cancel --pretty
a3s-flow new flow.cancel --id example-flow-cancel --pretty
a3s-flow validate workflow.json --pretty
a3s-flow compile workflow.json --pretty
a3s-flow digest workflow.json --pretty

Skill usage

The package includes the a3s-flow Skill. It queries the CLI catalog before creating, validating, compiling, and digesting a workflow.

Prompt

Use $a3s-flow to add the "flow.cancel" node to workflow.json, connect valid ports, and validate the result.

CLI usage · Skill usage

Operational notes

Do not use cancellation as an ordinary branch exit.
Give cleanup work fresh stable node identities.
Managed children still cleaning up block the parent outcome.

#Cancel workflow flow.cancel

#Cleanup order

#Race and recovery tests