---
summary: "Heartbeat polling messages and notification rules"
read_when:
  - Adjusting heartbeat cadence or messaging
  - Deciding between heartbeat and cron for scheduled tasks
title: "Heartbeat"
---

# Heartbeat (Gateway)

> **Heartbeat vs Cron?** See [Automation & Tasks](/automation) for guidance on when to use each.

Heartbeat runs **periodic agent turns** in the main session so the model can
surface anything that needs attention without spamming you.

Heartbeat is a scheduled main-session turn — it does **not** create [background task](/automation/tasks) records.
Task records are for detached work (ACP runs, subagents, isolated cron jobs).

Troubleshooting: [Scheduled Tasks](/automation/cron-jobs#troubleshooting)

## Quick start (beginner)

1. Leave heartbeats enabled (default is `30m`, or `1h` for Anthropic OAuth/token auth, including Claude CLI reuse) or set your own cadence.
2. Create a tiny `HEARTBEAT.md` checklist or `tasks:` block in the agent workspace (optional but recommended).
3. Decide where heartbeat messages should go (`target: "none"` is the default; set `target: "last"` to route to the last contact).
4. Optional: enable heartbeat reasoning delivery for transparency.
5. Optional: use lightweight bootstrap context if heartbeat runs only need `HEARTBEAT.md`.
6. Optional: enable isolated sessions to avoid sending full conversation history each heartbeat.
7. Optional: restrict heartbeats to active hours (local time).

Example config:

```json5
{
  agents: {
    defaults: {
      heartbeat: {
        every: "30m",
        target: "last", // explicit delivery to last contact (default is "none")
        directPolicy: "allow", // default: allow direct/DM targets; set "block" to suppress
        lightContext: true, // optional: only inject HEARTBEAT.md from bootstrap files
        isolatedSession: true, // optional: fresh session each run (no conversation history)
        // activeHours: { start: "08:00", end: "24:00" },
        // includeReasoning: true, // optional: send separate `Reasoning:` message too
      },
    },
  },
}
```

## Defaults

- Interval: `30m` (or `1h` when Anthropic OAuth/token auth is the detected auth mode, including Claude CLI reuse). Set `agents.defaults.heartbeat.every` or per-agent `agents.list[].heartbeat.every`; use `0m` to disable.
- Prompt body (configurable via `agents.defaults.heartbeat.prompt`):
  `Read HEARTBEAT.md if it exists (workspace context). Follow it strictly. Do not infer or repeat old tasks from prior chats. If nothing needs attention, reply HEARTBEAT_OK.`
- The heartbeat prompt is sent **verbatim** as the user message. The system
  prompt includes a “Heartbeat” section only when heartbeats are enabled for the
  default agent, and the run is flagged internally.
- When heartbeats are disabled with `0m`, normal runs also omit `HEARTBEAT.md`
  from bootstrap context so the model does not see heartbeat-only instructions.
- Active hours (`heartbeat.activeHours`) are checked in the configured timezone.
  Outside the window, heartbeats are skipped until the next tick inside the window.

## What the heartbeat prompt is for

The default prompt is intentionally broad:

- **Background tasks**: “Consider outstanding tasks” nudges the agent to review
  follow-ups (inbox, calendar, reminders, queued work) and surface anything urgent.
- **Human check-in**: “Checkup sometimes on your human during day time” nudges an
  occasional lightweight “anything you need?” message, but avoids night-time spam
  by using your configured local timezone (see [/concepts/timezone](/concepts/timezone)).

Heartbeat can react to completed [background tasks](/automation/tasks), but a heartbeat run itself does not create a task record.

If you want a heartbeat to do something very specific (e.g. “check Gmail PubSub
stats” or “verify gateway health”), set `agents.defaults.heartbeat.prompt` (or
`agents.list[].heartbeat.prompt`) to a custom body (sent verbatim).

## Response contract

- If nothing needs attention, reply with **`HEARTBEAT_OK`**.
- During heartbeat runs, KaijiBot treats `HEARTBEAT_OK` as an ack when it appears
  at the **start or end** of the reply. The token is stripped and the reply is
  dropped if the remaining content is **≤ `ackMaxChars`** (default: 300).
- If `HEARTBEAT_OK` appears in the **middle** of a reply, it is not treated
  specially.
- For alerts, **do not** include `HEARTBEAT_OK`; return only the alert text.

Outside heartbeats, stray `HEARTBEAT_OK` at the start/end of a message is stripped
and logged; a message that is only `HEARTBEAT_OK` is dropped.

## Config

```json5
{
  agents: {
    defaults: {
      heartbeat: {
        every: "30m", // default: 30m (0m disables)
        model: "anthropic/claude-opus-4-6",
        includeReasoning: false, // default: false (deliver separate Reasoning: message when available)
        lightContext: false, // default: false; true keeps only HEARTBEAT.md from workspace bootstrap files
        isolatedSession: false, // default: false; true runs each heartbeat in a fresh session (no conversation history)
        target: "last", // default: none | options: last | none | <channel id> (core or plugin, e.g. "bluebubbles")
        to: "+15551234567", // optional channel-specific override
        accountId: "ops-bot", // optional multi-account channel id
        prompt: "Read HEARTBEAT.md if it exists (workspace context). Follow it strictly. Do not infer or repeat old tasks from prior chats. If nothing needs attention, reply HEARTBEAT_OK.",
        ackMaxChars: 300, // max chars allowed after HEARTBEAT_OK
      },
    },
  },
}
```

### Scope and precedence

- `agents.defaults.heartbeat` sets global heartbeat behavior.
- `agents.list[].heartbeat` merges on top; if any agent has a `heartbeat` block, **only those agents** run heartbeats.
- `channels.defaults.heartbeat` sets visibility defaults for all channels.
- `channels.<channel>.heartbeat` overrides channel defaults.
- `channels.<channel>.accounts.<id>.heartbeat` (multi-account channels) overrides per-channel settings.

### Per-agent heartbeats

If any `agents.list[]` entry includes a `heartbeat` block, **only those agents**
run heartbeats. The per-agent block merges on top of `agents.defaults.heartbeat`
(so you can set shared defaults once and override per agent).

Example: two agents, only the second agent runs heartbeats.

```json5
{
  agents: {
    defaults: {
      heartbeat: {
        every: "30m",
        target: "last", // explicit delivery to last contact (default is "none")
      },
    },
    list: [
      { id: "main", default: true },
      {
        id: "ops",
        heartbeat: {
          every: "1h",
          target: "whatsapp",
          to: "+15551234567",
          prompt: "Read HEARTBEAT.md if it exists (workspace context). Follow it strictly. Do not infer or repeat old tasks from prior chats. If nothing needs attention, reply HEARTBEAT_OK.",
        },
      },
    ],
  },
}
```

### Active hours example

Restrict heartbeats to business hours in a specific timezone:

```json5
{
  agents: {
    defaults: {
      heartbeat: {
        every: "30m",
        target: "last", // explicit delivery to last contact (default is "none")
        activeHours: {
          start: "09:00",
          end: "22:00",
          timezone: "America/New_York", // optional; uses your userTimezone if set, otherwise host tz
        },
      },
    },
  },
}
```

Outside this window (before 9am or after 10pm Eastern), heartbeats are skipped. The next scheduled tick inside the window will run normally.

### 24/7 setup

If you want heartbeats to run all day, use one of these patterns:

- Omit `activeHours` entirely (no time-window restriction; this is the default behavior).
- Set a full-day window: `activeHours: { start: "00:00", end: "24:00" }`.

Do not set the same `start` and `end` time (for example `08:00` to `08:00`).
That is treated as a zero-width window, so heartbeats are always skipped.

### Multi account example

Use `accountId` to target a specific account on multi-account channels like Telegram:

```json5
{
  agents: {
    list: [
      {
        id: "ops",
        heartbeat: {
          every: "1h",
          target: "telegram",
          to: "12345678:topic:42", // optional: route to a specific topic/thread
          accountId: "ops-bot",
        },
      },
    ],
  },
  channels: {
    telegram: {
      accounts: {
        "ops-bot": { botToken: "YOUR_TELEGRAM_BOT_TOKEN" },
      },
    },
  },
}
```

### Field notes

- `every`: heartbeat interval (duration string; default unit = minutes).
- `model`: optional model override for heartbeat runs (`provider/model`).
- `includeReasoning`: when enabled, also deliver the separate `Reasoning:` message when available (same shape as `/reasoning on`).
- `lightContext`: when true, heartbeat runs use lightweight bootstrap context and keep only `HEARTBEAT.md` from workspace bootstrap files.
- `isolatedSession`: when true, each heartbeat runs in a fresh session with no prior conversation history. Uses the same isolation pattern as cron `sessionTarget: "isolated"`. Dramatically reduces per-heartbeat token cost. Combine with `lightContext: true` for maximum savings. Delivery routing still uses the main session context.
- `session`: optional session key for heartbeat runs.
  - `main` (default): agent main session.
  - Explicit session key (copy from `kaijibot sessions --json` or the [sessions CLI](/cli/sessions)).
  - Session key formats: see [Sessions](/concepts/session) and [Groups](/channels/groups).
- `target`:
  - `last`: deliver to the last used external channel.
  - explicit channel: any configured channel or plugin id, for example `discord`, `matrix`, `telegram`, or `whatsapp`.
  - `none` (default): run the heartbeat but **do not deliver** externally.
- `directPolicy`: controls direct/DM delivery behavior:
  - `allow` (default): allow direct/DM heartbeat delivery.
  - `block`: suppress direct/DM delivery (`reason=dm-blocked`).
- `to`: optional recipient override (channel-specific id, e.g. E.164 for WhatsApp or a Telegram chat id). For Telegram topics/threads, use `<chatId>:topic:<messageThreadId>`.
- `accountId`: optional account id for multi-account channels. When `target: "last"`, the account id applies to the resolved last channel if it supports accounts; otherwise it is ignored. If the account id does not match a configured account for the resolved channel, delivery is skipped.
- `prompt`: overrides the default prompt body (not merged).
- `ackMaxChars`: max chars allowed after `HEARTBEAT_OK` before delivery.
- `suppressToolErrorWarnings`: when true, suppresses tool error warning payloads during heartbeat runs.
- `activeHours`: restricts heartbeat runs to a time window. Object with `start` (HH:MM, inclusive; use `00:00` for start-of-day), `end` (HH:MM exclusive; `24:00` allowed for end-of-day), and optional `timezone`.
  - Omitted or `"user"`: uses your `agents.defaults.userTimezone` if set, otherwise falls back to the host system timezone.
  - `"local"`: always uses the host system timezone.
  - Any IANA identifier (e.g. `America/New_York`): used directly; if invalid, falls back to the `"user"` behavior above.
  - `start` and `end` must not be equal for an active window; equal values are treated as zero-width (always outside the window).
  - Outside the active window, heartbeats are skipped until the next tick inside the window.

## Delivery behavior

- Heartbeats run in the agent’s main session by default (`agent:<id>:<mainKey>`),
  or `global` when `session.scope = "global"`. Set `session` to override to a
  specific channel session (Discord/WhatsApp/etc.).
- `session` only affects the run context; delivery is controlled by `target` and `to`.
- To deliver to a specific channel/recipient, set `target` + `to`. With
  `target: "last"`, delivery uses the last external channel for that session.
- Heartbeat deliveries allow direct/DM targets by default. Set `directPolicy: "block"` to suppress direct-target sends while still running the heartbeat turn.
- If the main queue is busy, the heartbeat is skipped and retried later.
- If `target` resolves to no external destination, the run still happens but no
  outbound message is sent.
- If `showOk`, `showAlerts`, and `useIndicator` are all disabled, the run is skipped up front as `reason=alerts-disabled`.
- If only alert delivery is disabled, KaijiBot can still run the heartbeat, update due-task timestamps, restore the session idle timestamp, and suppress the outward alert payload.
- Heartbeat-only replies do **not** keep the session alive; the last `updatedAt`
  is restored so idle expiry behaves normally.
- Detached [background tasks](/automation/tasks) can enqueue a system event and wake heartbeat when the main session should notice something quickly. That wake does not make the heartbeat run a background task.

## Visibility controls

By default, `HEARTBEAT_OK` acknowledgments are suppressed while alert content is
delivered. You can adjust this per channel or per account:

```yaml
channels:
  defaults:
    heartbeat:
      showOk: false # Hide HEARTBEAT_OK (default)
      showAlerts: true # Show alert messages (default)
      useIndicator: true # Emit indicator events (default)
  telegram:
    heartbeat:
      showOk: true # Show OK acknowledgments on Telegram
  whatsapp:
    accounts:
      work:
        heartbeat:
          showAlerts: false # Suppress alert delivery for this account
```

Precedence: per-account → per-channel → channel defaults → built-in defaults.

### What each flag does

- `showOk`: sends a `HEARTBEAT_OK` acknowledgment when the model returns an OK-only reply.
- `showAlerts`: sends the alert content when the model returns a non-OK reply.
- `useIndicator`: emits indicator events for UI status surfaces.

If **all three** are false, KaijiBot skips the heartbeat run entirely (no model call).

### Per-channel vs per-account examples

```yaml
channels:
  defaults:
    heartbeat:
      showOk: false
      showAlerts: true
      useIndicator: true
  slack:
    heartbeat:
      showOk: true # all Slack accounts
    accounts:
      ops:
        heartbeat:
          showAlerts: false # suppress alerts for the ops account only
  telegram:
    heartbeat:
      showOk: true
```

### Common patterns

| Goal                                     | Config                                                                                   |
| ---------------------------------------- | ---------------------------------------------------------------------------------------- |
| Default behavior (silent OKs, alerts on) | _(no config needed)_                                                                     |
| Fully silent (no messages, no indicator) | `channels.defaults.heartbeat: { showOk: false, showAlerts: false, useIndicator: false }` |
| Indicator-only (no messages)             | `channels.defaults.heartbeat: { showOk: false, showAlerts: false, useIndicator: true }`  |
| OKs in one channel only                  | `channels.telegram.heartbeat: { showOk: true }`                                          |

## HEARTBEAT.md (optional)

If a `HEARTBEAT.md` file exists in the workspace, the default prompt tells the
agent to read it. Think of it as your “heartbeat checklist”: small, stable, and
safe to include every 30 minutes.

On normal runs, `HEARTBEAT.md` is only injected when heartbeat guidance is
enabled for the default agent. Disabling the heartbeat cadence with `0m` or
setting `includeSystemPromptSection: false` omits it from normal bootstrap
context.

If `HEARTBEAT.md` exists but is effectively empty (only blank lines and markdown
headers like `# Heading`), KaijiBot skips the heartbeat run to save API calls.
That skip is reported as `reason=empty-heartbeat-file`.
If the file is missing, the heartbeat still runs and the model decides what to do.

Keep it tiny (short checklist or reminders) to avoid prompt bloat.

Example `HEARTBEAT.md`:

```md
# Heartbeat checklist

- Quick scan: anything urgent in inboxes?
- If it’s daytime, do a lightweight check-in if nothing else is pending.
- If a task is blocked, write down _what is missing_ and ask Peter next time.
```

### `tasks:` blocks

`HEARTBEAT.md` also supports a small structured `tasks:` block for interval-based
checks inside heartbeat itself.

Example:

```md
tasks:

- name: inbox-triage
  interval: 30m
  prompt: "Check for urgent unread emails and flag anything time sensitive."
- name: calendar-scan
  interval: 2h
  prompt: "Check for upcoming meetings that need prep or follow-up."

# Additional instructions

- Keep alerts short.
- If nothing needs attention after all due tasks, reply HEARTBEAT_OK.
```

Behavior:

- KaijiBot parses the `tasks:` block and checks each task against its own `interval`.
- Only **due** tasks are included in the heartbeat prompt for that tick.
- If no tasks are due, the heartbeat is skipped entirely (`reason=no-tasks-due`) to avoid a wasted model call.
- Non-task content in `HEARTBEAT.md` is preserved and appended as additional context after the due-task list.
- Task last-run timestamps are stored in session state (`heartbeatTaskState`), so intervals survive normal restarts.
- Task timestamps are only advanced after a heartbeat run completes its normal reply path. Skipped `empty-heartbeat-file` / `no-tasks-due` runs do not mark tasks as completed.

Task mode is useful when you want one heartbeat file to hold several periodic checks without paying for all of them every tick.

### Can the agent update HEARTBEAT.md?

Yes — if you ask it to.

`HEARTBEAT.md` is just a normal file in the agent workspace, so you can tell the
agent (in a normal chat) something like:

- “Update `HEARTBEAT.md` to add a daily calendar check.”
- “Rewrite `HEARTBEAT.md` so it’s shorter and focused on inbox follow-ups.”

If you want this to happen proactively, you can also include an explicit line in
your heartbeat prompt like: “If the checklist becomes stale, update HEARTBEAT.md
with a better one.”

Safety note: don’t put secrets (API keys, phone numbers, private tokens) into
`HEARTBEAT.md` — it becomes part of the prompt context.

## Manual wake (on-demand)

You can enqueue a system event and trigger an immediate heartbeat with:

```bash
kaijibot system event --text "Check for urgent follow-ups" --mode now
```

If multiple agents have `heartbeat` configured, a manual wake runs each of those
agent heartbeats immediately.

Use `--mode next-heartbeat` to wait for the next scheduled tick.

## Reasoning delivery (optional)

By default, heartbeats deliver only the final “answer” payload.

If you want transparency, enable:

- `agents.defaults.heartbeat.includeReasoning: true`

When enabled, heartbeats will also deliver a separate message prefixed
`Reasoning:` (same shape as `/reasoning on`). This can be useful when the agent
is managing multiple sessions/codexes and you want to see why it decided to ping
you — but it can also leak more internal detail than you want. Prefer keeping it
off in group chats.

## Cost awareness

Heartbeats run full agent turns. Shorter intervals burn more tokens. To reduce cost:

- Use `isolatedSession: true` to avoid sending full conversation history (~100K tokens down to ~2-5K per run).
- Use `lightContext: true` to limit bootstrap files to just `HEARTBEAT.md`.
- Set a cheaper `model` (e.g. `ollama/llama3.2:1b`).
- Keep `HEARTBEAT.md` small.
- Use `target: "none"` if you only want internal state updates.

## Related

- [Automation & Tasks](/automation) — all automation mechanisms at a glance
- [Background Tasks](/automation/tasks) — how detached work is tracked
- [Timezone](/concepts/timezone) — how timezone affects heartbeat scheduling
- [Troubleshooting](/automation/cron-jobs#troubleshooting) — debugging automation issues
