Temporal Signals: Human-in-the-Loop and Manual Approval Workflows

Sun, 22 Feb 2026 00:00:00 +0000

Temporal Signals#

Workflows often need input after they have started. A deployment workflow pauses for human approval. An expense workflow waits for a manager’s signature. An incident response workflow escalates after a timeout. Temporal signals are the mechanism for delivering external input to a running workflow.

A signal is a message sent to a workflow from outside – from another workflow, from a CLI command, from an HTTP endpoint, or from any system that has the Temporal client. The workflow receives the signal, processes it, and continues execution. Signals are durable: if the worker crashes after a signal is sent but before the workflow processes it, the signal is replayed when the worker restarts.

Temporal Signals for Automated Coordination: Locking, Blocking, and Cross-Workflow Communication

Sun, 22 Feb 2026 00:00:00 +0000

Temporal Signals for Automated Coordination#

In Temporal Signals for Manual Interaction, you learned how external systems and humans send signals to running workflows. Signals are not limited to human input. They are a general-purpose communication channel between workflows, and they become powerful coordination primitives when workflows signal each other programmatically.

This article covers automated signal patterns: cross-workflow signaling, distributed mutexes built on signals, blocking semantics, and the anti-patterns that will burn you.

Signals on Agent Zone

Temporal Signals: Human-in-the-Loop and Manual Approval Workflows

Temporal Signals#

Temporal Signals for Automated Coordination: Locking, Blocking, and Cross-Workflow Communication

Temporal Signals for Automated Coordination#