---
slug: "Heartbeat"
name: "Heartbeat"
type: "Primitives"
layer: "Infrastructure"
ref: "Heartbeat#c5df"
sema_id: "sema:Heartbeat#mh:SHA-256:c5dfefe91d5460716f19e001290b47c3853173b17f0b6914793f6f51a41903ef"
tags: ["Infrastructure","Primitives"]
updated: 2026-11-11
mindscape: "bootstrap"
index_url: https://mindscape.world/scapes/bootstrap.json
url: https://mindscape.world/bootstrap/Heartbeat/
related: ["Signal","Quorum","Monitor","Delegate","ExplainBeacon","QuorumPulse","Responsibility","TaskLifecycle"]
---

# Heartbeat

Liveness detection via periodic signals

Layer: Infrastructure · Category: Primitives

## Mechanism

Periodic Liveness [Signal](https://mindscape.world/scapes/bootstrap/Signal.md): An entity emits [Signal](https://mindscape.world/scapes/bootstrap/Signal.md) (Heartbeat) every interval I. Missing K consecutive heartbeats triggers failure detection. Heartbeat may include health metrics. Receiver tracks last-seen timestamp. It feeds into the [Quorum](https://mindscape.world/scapes/bootstrap/Quorum.md) detector, allowing the collective to identify and prune dead nodes.

## Invariants

- Missing `timeout_multiplier` consecutive intervals triggers failure DETECTION, which is a suspicion and not a fact about the emitter.
- Emission interval stays within `interval`.

## Preconditions

- Active component
- [Monitor](https://mindscape.world/scapes/bootstrap/Monitor.md)

## Postconditions

- Liveness confirmed

## Failure modes

- False failure detection: the node is alive and its heartbeat was delayed, so absence of signal was read as absence of the emitter.
- Heartbeat outlives usefulness: the emitter is alive and the work it was doing is not, so liveness is reported while progress has stopped.

## Parameters

- `interval` (Duration, [100ms, 60s]): Time between heartbeats
- `timeout_multiplier` (Integer, [2, 5]): Missed beats before failure

## Builds on

- [Signal](https://mindscape.world/scapes/bootstrap/Signal.md) (Infrastructure; Accepts)
- [Quorum](https://mindscape.world/scapes/bootstrap/Quorum.md) (Infrastructure; Composes with)
- [Monitor](https://mindscape.world/scapes/bootstrap/Monitor.md) (Infrastructure; References)

## Used by

- [Delegate](https://mindscape.world/scapes/bootstrap/Delegate.md) (Society; Composes with)
- [ExplainBeacon](https://mindscape.world/scapes/bootstrap/ExplainBeacon.md) (Infrastructure; References)
- [QuorumPulse](https://mindscape.world/scapes/bootstrap/QuorumPulse.md) (Society; References)
- [Responsibility](https://mindscape.world/scapes/bootstrap/Responsibility.md) (Society; References)
- [TaskLifecycle](https://mindscape.world/scapes/bootstrap/TaskLifecycle.md) (Infrastructure; References)

## Identity

- Sema ID: `sema:Heartbeat#mh:SHA-256:c5dfefe91d5460716f19e001290b47c3853173b17f0b6914793f6f51a41903ef`
- Ref: `Heartbeat#c5df`
- Supersedes:
  - `sema:Heartbeat#mh:SHA-256:7f881d347e8ead278efa6ee9abb5ce8c50f1ea70d38f485cb2c4e911457702b2`
  - `sema:Heartbeat#mh:SHA-256:d0e6ffd899704efd75b87f0365bbe48fec4a1179b81e08923779ed84be7c83c2`
  - `sema:Heartbeat#mh:SHA-256:c36fe65a4b171559a33cb36f37ec448dce8ad7092c665426bfabee3dbeb6d1c1`

## Links

- [Pattern page](https://mindscape.world/bootstrap/Heartbeat/)
- [View in the interactive graph](https://mindscape.world/bootstrap/#Heartbeat)
- [JSON](https://mindscape.world/scapes/bootstrap/Heartbeat.json)
- [Index of all patterns](https://mindscape.world/scapes/bootstrap.json)