diff --git a/docs/PLG-CAL-001-calendar-heartbeat-format.md b/docs/PLG-CAL-001-calendar-heartbeat-format.md
new file mode 100644
index 0000000..687fd5e
--- /dev/null
+++ b/docs/PLG-CAL-001-calendar-heartbeat-format.md
@@ -0,0 +1,261 @@
+# PLG-CAL-001 — Calendar Heartbeat Format Specification
+
+> **Task:** HarborForge OpenclawPlugin / Monitor 联动  
+> **Subtask:** PLG-CAL-001 — 插件侧定义 Calendar 心跳请求格式  
+> **Status:** ✅ Implemented (types + client + spec)  
+> **Date:** 2026-04-01
+
+---
+
+## Overview
+
+This document specifies the request/response format for the Calendar heartbeat
+communication between the OpenClaw HarborForge plugin and the HarborForge backend.
+
+Heartbeat direction: **Plugin → Backend**
+
+The plugin sends a heartbeat every minute (aligned with the existing Monitor
+heartbeat interval). The backend returns today's pending TimeSlots for the agent.
+
+---
+
+## 1. How `claw_identifier` is Determined
+
+`claw_identifier` identifies the server/claw instance. It is the same value used
+in the Monitor heartbeat system (`MonitoredServer.identifier`).
+
+**Priority order:**
+
+1. **`config.identifier`** — if set in the plugin config (`harbor-forge.identifier`)
+2. **`os.hostname()`** — auto-detected from the machine hostname (fallback)
+
+```typescript
+// In plugin/calendar/calendar-bridge.ts
+const clawIdentifier = baseConfig.identifier || hostname();
+```
+
+---
+
+## 2. How `agent_id` is Determined
+
+`agent_id` is the OpenClaw agent identifier (`$AGENT_ID`).
+
+- Set by OpenClaw at agent startup as an environment variable
+- The plugin reads it via `process.env.AGENT_ID`
+- Globally unique within a single OpenClaw gateway deployment
+
+```typescript
+// In plugin/index.ts (caller)
+const agentId = process.env.AGENT_ID || 'unknown';
+```
+
+---
+
+## 3. Heartbeat Request
+
+**Endpoint:** `GET /calendar/agent/heartbeat`
+
+### Headers
+
+| Header | Value | Notes |
+|--------|-------|-------|
+| `Content-Type` | `application/json` | Always set |
+| `X-Agent-ID` | `$AGENT_ID` | OpenClaw agent identifier |
+| `X-Claw-Identifier` | `claw_identifier` | Server identifier |
+
+### Request Body (JSON)
+
+```json
+{
+  "claw_identifier": "srv1390517",
+  "agent_id": "developer"
+}
+```
+
+### Field Definitions
+
+| Field | Type | Source | Notes |
+|-------|------|--------|-------|
+| `claw_identifier` | string | Plugin config or `hostname()` | Identifies the OpenClaw server instance |
+| `agent_id` | string | `process.env.AGENT_ID` | Identifies the agent session |
+
+---
+
+## 4. Heartbeat Response
+
+### Success (HTTP 200)
+
+```json
+{
+  "slots": [
+    {
+      "id": 42,
+      "virtual_id": null,
+      "user_id": 1,
+      "date": "2026-04-01",
+      "slot_type": "work",
+      "estimated_duration": 30,
+      "scheduled_at": "09:00:00",
+      "started_at": null,
+      "attended": false,
+      "actual_duration": null,
+      "event_type": "job",
+      "event_data": {
+        "type": "Task",
+        "code": "TASK-123"
+      },
+      "priority": 50,
+      "status": "not_started",
+      "plan_id": null
+    }
+  ],
+  "agent_status": "idle",
+  "message": "2 slots pending"
+}
+```
+
+### Field Definitions
+
+| Field | Type | Notes |
+|-------|------|-------|
+| `slots` | `CalendarSlotResponse[]` | Pending slots, sorted by `priority` DESC |
+| `agent_status` | `AgentStatusValue` | Current backend-observed agent status |
+| `message` | string (optional) | Human-readable summary |
+
+### `CalendarSlotResponse` Fields
+
+| Field | Type | Notes |
+|-------|------|-------|
+| `id` | `number \| null` | Real slot DB id. `null` for virtual slots. |
+| `virtual_id` | `string \| null` | `plan-{plan_id}-{date}`. `null` for real slots. |
+| `user_id` | number | Owner HarborForge user id |
+| `date` | string | ISO date `YYYY-MM-DD` |
+| `slot_type` | `SlotType` | `work \| on_call \| entertainment \| system` |
+| `estimated_duration` | number | Minutes (1-50) |
+| `scheduled_at` | string | ISO time `HH:MM:SS` |
+| `started_at` | `string \| null` | Actual start time when slot begins |
+| `attended` | boolean | `true` once agent begins the slot |
+| `actual_duration` | `number \| null` | Real minutes when slot finishes |
+| `event_type` | `EventType \| null` | `job \| entertainment \| system_event` |
+| `event_data` | object \| null | See §4a below |
+| `priority` | number | 0-99, higher = more urgent |
+| `status` | `SlotStatus` | `not_started \| deferred \| ...` |
+| `plan_id` | `number \| null` | Source plan if materialized from SchedulePlan |
+
+### §4a — `event_data` Shapes
+
+**When `event_type == "job"`:**
+```json
+{
+  "type": "Task",
+  "code": "TASK-42",
+  "working_sessions": ["session-id-1"]
+}
+```
+
+**When `event_type == "system_event"`:**
+```json
+{
+  "event": "ScheduleToday"
+}
+```
+Valid events: `ScheduleToday | SummaryToday | ScheduledGatewayRestart`
+
+---
+
+## 5. Slot Update Requests (Plugin → Backend after execution)
+
+After attending / finishing / deferring a slot, the plugin calls:
+
+**Real slot:** `PATCH /calendar/slots/{slot_id}/agent-update`
+**Virtual slot:** `PATCH /calendar/slots/virtual/{virtual_id}/agent-update`
+
+### Headers
+
+Same as heartbeat (see §3).
+
+### Request Body
+
+```json
+{
+  "status": "ongoing",
+  "started_at": "09:02:31",
+  "actual_duration": null
+}
+```
+
+| Field | Type | Required | Notes |
+|-------|------|----------|-------|
+| `status` | `SlotStatus` | **Required** | New status after agent action |
+| `started_at` | string | On attending | ISO time `HH:MM:SS` |
+| `actual_duration` | number | On finishing | Real minutes |
+
+### Status Transition Values
+
+| Action | `status` value |
+|--------|---------------|
+| Agent begins slot | `ongoing` |
+| Agent finishes slot | `finished` |
+| Agent defers slot | `deferred` |
+| Agent aborts slot | `aborted` |
+| Agent pauses slot | `paused` |
+
+---
+
+## 6. Backend Endpoint Summary
+
+| Method | Path | Auth | Description |
+|--------|------|------|-------------|
+| GET | `/calendar/agent/heartbeat` | X-Agent-ID + X-Claw-Identifier | Fetch pending slots for today |
+| PATCH | `/calendar/slots/{id}/agent-update` | X-Agent-ID + X-Claw-Identifier | Update real slot status |
+| PATCH | `/calendar/slots/virtual/{vid}/agent-update` | X-Agent-ID + X-Claw-Identifier | Update virtual slot status |
+| POST | `/calendar/agent/status` | X-Agent-ID + X-Claw-Identifier | Report agent status change |
+
+---
+
+## 7. Error Handling
+
+- **Backend unreachable:** Plugin logs warning, returns `null` from heartbeat.  
+  Agent continues to operate without Calendar integration.
+- **Invalid credentials (401/403):** Logged as error. No retry on same interval.
+- **Rate limiting (429):** Plugin should mark agent as `Exhausted` and not retry
+  until the `Retry-After` header indicates.
+
+---
+
+## 8. TypeScript Reference
+
+Full type definitions are in `plugin/calendar/types.ts`:
+
+```typescript
+// Request
+interface CalendarHeartbeatRequest {
+  claw_identifier: string;
+  agent_id: string;
+}
+
+// Response
+interface CalendarHeartbeatResponse {
+  slots: CalendarSlotResponse[];
+  agent_status: AgentStatusValue;
+  message?: string;
+}
+
+// Slot update
+interface SlotAgentUpdate {
+  status: SlotStatus;
+  started_at?: string;   // ISO time HH:MM:SS
+  actual_duration?: number;
+}
+```
+
+---
+
+## 9. Implementation Files
+
+| File | Purpose |
+|------|---------|
+| `plugin/calendar/types.ts` | TypeScript interfaces for all request/response shapes |
+| `plugin/calendar/calendar-bridge.ts` | `CalendarBridgeClient` HTTP client |
+| `plugin/calendar/index.ts` | Module entry point |
+| `docs/PLG-CAL-001-calendar-heartbeat-format.md` | This specification |
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..60eb846
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,17 @@
+{
+  "name": "harbor-forge-openclaw-plugin",
+  "version": "0.2.0",
+  "lockfileVersion": 3,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "harbor-forge-openclaw-plugin",
+      "version": "0.2.0",
+      "hasInstallScript": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=18.0.0"
+      }
+    }
+  }
+}
diff --git a/plugin/calendar/calendar-bridge.d.ts b/plugin/calendar/calendar-bridge.d.ts
new file mode 100644
index 0000000..cae6d50
--- /dev/null
+++ b/plugin/calendar/calendar-bridge.d.ts
@@ -0,0 +1,124 @@
+/**
+ * HarborForge Calendar Bridge Client
+ *
+ * PLG-CAL-001: Handles HTTP communication between the OpenClaw plugin
+ * and the HarborForge backend for Calendar heartbeat and slot updates.
+ *
+ * Request authentication:
+ *   • X-Agent-ID header — set to process.env.AGENT_ID
+ *   • X-Claw-Identifier header — set to the server's claw_identifier
+ *     (from plugin config or hostname fallback)
+ *
+ * Base URL:
+ *   Derived from plugin config: backendUrl + "/calendar"
+ *   Default backendUrl: "https://monitor.hangman-lab.top"
+ *
+ * Endpoints used:
+ *   GET  /calendar/agent/heartbeat        — fetch pending slots
+ *   PATCH /calendar/slots/{id}/agent-update   — update real slot status
+ *   PATCH /calendar/slots/virtual/{vid}/agent-update — update virtual slot status
+ *
+ * References:
+ *   • NEXT_WAVE_DEV_DIRECTION.md §6.1 (Heartbeat flow)
+ *   • HarborForge.Backend/app/services/agent_heartbeat.py (BE-AGT-001)
+ */
+import { CalendarHeartbeatResponse, CalendarSlotResponse, SlotAgentUpdate } from './types';
+export interface CalendarBridgeConfig {
+    /** HarborForge backend base URL (e.g. "https://monitor.hangman-lab.top") */
+    backendUrl: string;
+    /** Server/claw identifier (from plugin config or hostname fallback) */
+    clawIdentifier: string;
+    /** OpenClaw agent ID ($AGENT_ID), set at agent startup */
+    agentId: string;
+    /** HTTP request timeout in milliseconds (default: 5000) */
+    timeoutMs?: number;
+}
+export declare class CalendarBridgeClient {
+    private baseUrl;
+    private config;
+    private timeoutMs;
+    constructor(config: CalendarBridgeConfig);
+    /**
+     * Fetch today's pending calendar slots for this agent.
+     *
+     * Heartbeat flow (§6.1):
+     *  1. Plugin sends heartbeat every minute
+     *  2. Backend returns slots where status is NotStarted or Deferred
+     *     AND scheduled_at <= now
+     *  3. Plugin selects highest-priority slot (if any)
+     *  4. For remaining slots, plugin sets status = Deferred + priority += 1
+     *
+     * @returns CalendarHeartbeatResponse or null if the backend is unreachable
+     */
+    heartbeat(): Promise<CalendarHeartbeatResponse | null>;
+    /**
+     * Update a real (materialized) slot's status after agent execution.
+     *
+     * Used by the plugin to report:
+     *   - Slot attended (attended=true, started_at=now, status=Ongoing)
+     *   - Slot finished (actual_duration set, status=Finished)
+     *   - Slot deferred (status=Deferred, priority += 1)
+     *   - Slot aborted (status=Aborted)
+     *
+     * @param slotId  Real slot DB id
+     * @param update  Status update payload
+     * @returns true on success, false on failure
+     */
+    updateSlot(slotId: number, update: SlotAgentUpdate): Promise<boolean>;
+    /**
+     * Update a virtual (plan-generated) slot's status after agent execution.
+     *
+     * When updating a virtual slot, the backend first materializes it
+     * (creates a real TimeSlot row), then applies the update.
+     * The returned slot will have a real id on subsequent calls.
+     *
+     * @param virtualId  Virtual slot id in format "plan-{plan_id}-{date}"
+     * @param update     Status update payload
+     * @returns Updated CalendarSlotResponse on success, null on failure
+     */
+    updateVirtualSlot(virtualId: string, update: SlotAgentUpdate): Promise<CalendarSlotResponse | null>;
+    /**
+     * Report the agent's current runtime status to HarborForge.
+     *
+     * Used to push agent status transitions:
+     *   idle → busy / on_call  (when starting a slot)
+     *   busy / on_call → idle  (when finishing a slot)
+     *   → exhausted (on rate-limit / billing error, with recovery_at)
+     *   → offline (after 2 min with no heartbeat)
+     *
+     * @param status  New agent status
+     * @param recoveryAt  ISO timestamp for expected Exhausted recovery (optional)
+     * @param exhaustReason "rate_limit" | "billing" (required if status=exhausted)
+     */
+    reportAgentStatus(params: {
+        status: 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline';
+        recoveryAt?: string;
+        exhaustReason?: 'rate_limit' | 'billing';
+    }): Promise<boolean>;
+    private fetchJson;
+    private postBoolean;
+}
+export interface CalendarPluginConfig {
+    /** Backend URL for calendar API (overrides monitor backendUrl) */
+    calendarBackendUrl?: string;
+    /** Server identifier (overrides auto-detected hostname) */
+    identifier?: string;
+    /** Agent ID from OpenClaw ($AGENT_ID) */
+    agentId: string;
+    /** HTTP timeout for calendar API calls (default: 5000) */
+    timeoutMs?: number;
+}
+/**
+ * Build a CalendarBridgeClient from the OpenClaw plugin API context.
+ *
+ * @param api           OpenClaw plugin API (register() receives this)
+ * @param fallbackUrl   Fallback backend URL if not configured
+ * @param agentId       $AGENT_ID from OpenClaw environment
+ */
+export declare function createCalendarBridgeClient(api: {
+    config?: Record<string, unknown>;
+    logger?: {
+        debug?: (...args: unknown[]) => void;
+    };
+}, fallbackUrl: string, agentId: string): CalendarBridgeClient;
+//# sourceMappingURL=calendar-bridge.d.ts.map
\ No newline at end of file
diff --git a/plugin/calendar/calendar-bridge.d.ts.map b/plugin/calendar/calendar-bridge.d.ts.map
new file mode 100644
index 0000000..d83c24e
--- /dev/null
+++ b/plugin/calendar/calendar-bridge.d.ts.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/plugin/calendar/calendar-bridge.js b/plugin/calendar/calendar-bridge.js
new file mode 100644
index 0000000..3ac6578
--- /dev/null
+++ b/plugin/calendar/calendar-bridge.js
@@ -0,0 +1,214 @@
+"use strict";
+/**
+ * HarborForge Calendar Bridge Client
+ *
+ * PLG-CAL-001: Handles HTTP communication between the OpenClaw plugin
+ * and the HarborForge backend for Calendar heartbeat and slot updates.
+ *
+ * Request authentication:
+ *   • X-Agent-ID header — set to process.env.AGENT_ID
+ *   • X-Claw-Identifier header — set to the server's claw_identifier
+ *     (from plugin config or hostname fallback)
+ *
+ * Base URL:
+ *   Derived from plugin config: backendUrl + "/calendar"
+ *   Default backendUrl: "https://monitor.hangman-lab.top"
+ *
+ * Endpoints used:
+ *   GET  /calendar/agent/heartbeat        — fetch pending slots
+ *   PATCH /calendar/slots/{id}/agent-update   — update real slot status
+ *   PATCH /calendar/slots/virtual/{vid}/agent-update — update virtual slot status
+ *
+ * References:
+ *   • NEXT_WAVE_DEV_DIRECTION.md §6.1 (Heartbeat flow)
+ *   • HarborForge.Backend/app/services/agent_heartbeat.py (BE-AGT-001)
+ */
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.CalendarBridgeClient = void 0;
+exports.createCalendarBridgeClient = createCalendarBridgeClient;
+class CalendarBridgeClient {
+    baseUrl;
+    config;
+    timeoutMs;
+    constructor(config) {
+        this.baseUrl = config.backendUrl.replace(/\/$/, ''); // strip trailing slash
+        this.config = {
+            timeoutMs: 5000,
+            ...config,
+        };
+        this.timeoutMs = this.config.timeoutMs;
+    }
+    /**
+     * Fetch today's pending calendar slots for this agent.
+     *
+     * Heartbeat flow (§6.1):
+     *  1. Plugin sends heartbeat every minute
+     *  2. Backend returns slots where status is NotStarted or Deferred
+     *     AND scheduled_at <= now
+     *  3. Plugin selects highest-priority slot (if any)
+     *  4. For remaining slots, plugin sets status = Deferred + priority += 1
+     *
+     * @returns CalendarHeartbeatResponse or null if the backend is unreachable
+     */
+    async heartbeat() {
+        const url = `${this.baseUrl}/calendar/agent/heartbeat`;
+        const body = {
+            claw_identifier: this.config.clawIdentifier,
+            agent_id: this.config.agentId,
+        };
+        try {
+            const response = await this.fetchJson(url, {
+                method: 'GET',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'X-Agent-ID': this.config.agentId,
+                    'X-Claw-Identifier': this.config.clawIdentifier,
+                },
+                body: JSON.stringify(body),
+            });
+            return response;
+        }
+        catch (err) {
+            // Non-fatal: backend unreachable — return null, plugin continues
+            return null;
+        }
+    }
+    /**
+     * Update a real (materialized) slot's status after agent execution.
+     *
+     * Used by the plugin to report:
+     *   - Slot attended (attended=true, started_at=now, status=Ongoing)
+     *   - Slot finished (actual_duration set, status=Finished)
+     *   - Slot deferred (status=Deferred, priority += 1)
+     *   - Slot aborted (status=Aborted)
+     *
+     * @param slotId  Real slot DB id
+     * @param update  Status update payload
+     * @returns true on success, false on failure
+     */
+    async updateSlot(slotId, update) {
+        const url = `${this.baseUrl}/calendar/slots/${slotId}/agent-update`;
+        return this.postBoolean(url, update);
+    }
+    /**
+     * Update a virtual (plan-generated) slot's status after agent execution.
+     *
+     * When updating a virtual slot, the backend first materializes it
+     * (creates a real TimeSlot row), then applies the update.
+     * The returned slot will have a real id on subsequent calls.
+     *
+     * @param virtualId  Virtual slot id in format "plan-{plan_id}-{date}"
+     * @param update     Status update payload
+     * @returns Updated CalendarSlotResponse on success, null on failure
+     */
+    async updateVirtualSlot(virtualId, update) {
+        const url = `${this.baseUrl}/calendar/slots/virtual/${encodeURIComponent(virtualId)}/agent-update`;
+        try {
+            const response = await this.fetchJson(url, {
+                method: 'PATCH',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'X-Agent-ID': this.config.agentId,
+                    'X-Claw-Identifier': this.config.clawIdentifier,
+                },
+                body: JSON.stringify(update),
+            });
+            return response?.slot ?? null;
+        }
+        catch {
+            return null;
+        }
+    }
+    /**
+     * Report the agent's current runtime status to HarborForge.
+     *
+     * Used to push agent status transitions:
+     *   idle → busy / on_call  (when starting a slot)
+     *   busy / on_call → idle  (when finishing a slot)
+     *   → exhausted (on rate-limit / billing error, with recovery_at)
+     *   → offline (after 2 min with no heartbeat)
+     *
+     * @param status  New agent status
+     * @param recoveryAt  ISO timestamp for expected Exhausted recovery (optional)
+     * @param exhaustReason "rate_limit" | "billing" (required if status=exhausted)
+     */
+    async reportAgentStatus(params) {
+        const url = `${this.baseUrl}/calendar/agent/status`;
+        const body = {
+            agent_id: this.config.agentId,
+            claw_identifier: this.config.clawIdentifier,
+            ...params,
+        };
+        return this.postBoolean(url, body);
+    }
+    // -------------------------------------------------------------------------
+    // Internal helpers
+    // -------------------------------------------------------------------------
+    async fetchJson(url, init) {
+        const controller = new AbortController();
+        const timeout = setTimeout(() => controller.abort(), this.timeoutMs);
+        try {
+            const response = await fetch(url, {
+                ...init,
+                signal: controller.signal,
+            });
+            clearTimeout(timeout);
+            if (!response.ok)
+                return null;
+            return (await response.json());
+        }
+        catch {
+            clearTimeout(timeout);
+            return null;
+        }
+    }
+    async postBoolean(url, body) {
+        const controller = new AbortController();
+        const timeout = setTimeout(() => controller.abort(), this.timeoutMs);
+        try {
+            const response = await fetch(url, {
+                method: 'POST',
+                headers: {
+                    'Content-Type': 'application/json',
+                    'X-Agent-ID': this.config.agentId,
+                    'X-Claw-Identifier': this.config.clawIdentifier,
+                },
+                body: JSON.stringify(body),
+                signal: controller.signal,
+            });
+            clearTimeout(timeout);
+            return response.ok;
+        }
+        catch {
+            clearTimeout(timeout);
+            return false;
+        }
+    }
+}
+exports.CalendarBridgeClient = CalendarBridgeClient;
+// ---------------------------------------------------------------------------
+// Utility: build CalendarBridgeConfig from plugin API context
+// ---------------------------------------------------------------------------
+const os_1 = require("os");
+const live_config_1 = require("../core/live-config");
+/**
+ * Build a CalendarBridgeClient from the OpenClaw plugin API context.
+ *
+ * @param api           OpenClaw plugin API (register() receives this)
+ * @param fallbackUrl   Fallback backend URL if not configured
+ * @param agentId       $AGENT_ID from OpenClaw environment
+ */
+function createCalendarBridgeClient(api, fallbackUrl, agentId) {
+    const baseConfig = (0, live_config_1.getLivePluginConfig)(api, {
+        backendUrl: fallbackUrl,
+        identifier: (0, os_1.hostname)(),
+    });
+    const clawIdentifier = baseConfig.identifier || (0, os_1.hostname)();
+    return new CalendarBridgeClient({
+        backendUrl: baseConfig.backendUrl || fallbackUrl,
+        clawIdentifier,
+        agentId,
+        timeoutMs: 5000,
+    });
+}
+//# sourceMappingURL=calendar-bridge.js.map
\ No newline at end of file
diff --git a/plugin/calendar/calendar-bridge.js.map b/plugin/calendar/calendar-bridge.js.map
new file mode 100644
index 0000000..f62de25
--- /dev/null
+++ b/plugin/calendar/calendar-bridge.js.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/plugin/calendar/calendar-bridge.ts b/plugin/calendar/calendar-bridge.ts
new file mode 100644
index 0000000..71ffce1
--- /dev/null
+++ b/plugin/calendar/calendar-bridge.ts
@@ -0,0 +1,265 @@
+/**
+ * HarborForge Calendar Bridge Client
+ *
+ * PLG-CAL-001: Handles HTTP communication between the OpenClaw plugin
+ * and the HarborForge backend for Calendar heartbeat and slot updates.
+ *
+ * Request authentication:
+ *   • X-Agent-ID header — set to process.env.AGENT_ID
+ *   • X-Claw-Identifier header — set to the server's claw_identifier
+ *     (from plugin config or hostname fallback)
+ *
+ * Base URL:
+ *   Derived from plugin config: backendUrl + "/calendar"
+ *   Default backendUrl: "https://monitor.hangman-lab.top"
+ *
+ * Endpoints used:
+ *   GET  /calendar/agent/heartbeat        — fetch pending slots
+ *   PATCH /calendar/slots/{id}/agent-update   — update real slot status
+ *   PATCH /calendar/slots/virtual/{vid}/agent-update — update virtual slot status
+ *
+ * References:
+ *   • NEXT_WAVE_DEV_DIRECTION.md §6.1 (Heartbeat flow)
+ *   • HarborForge.Backend/app/services/agent_heartbeat.py (BE-AGT-001)
+ */
+
+import {
+  CalendarHeartbeatRequest,
+  CalendarHeartbeatResponse,
+  CalendarSlotResponse,
+  SlotAgentUpdate,
+  SlotStatus,
+} from './types';
+
+export interface CalendarBridgeConfig {
+  /** HarborForge backend base URL (e.g. "https://monitor.hangman-lab.top") */
+  backendUrl: string;
+  /** Server/claw identifier (from plugin config or hostname fallback) */
+  clawIdentifier: string;
+  /** OpenClaw agent ID ($AGENT_ID), set at agent startup */
+  agentId: string;
+  /** HTTP request timeout in milliseconds (default: 5000) */
+  timeoutMs?: number;
+}
+
+export class CalendarBridgeClient {
+  private baseUrl: string;
+  private config: Required<CalendarBridgeConfig>;
+  private timeoutMs: number;
+
+  constructor(config: CalendarBridgeConfig) {
+    this.baseUrl = config.backendUrl.replace(/\/$/, ''); // strip trailing slash
+    this.config = {
+      timeoutMs: 5000,
+      ...config,
+    };
+    this.timeoutMs = this.config.timeoutMs;
+  }
+
+  /**
+   * Fetch today's pending calendar slots for this agent.
+   *
+   * Heartbeat flow (§6.1):
+   *  1. Plugin sends heartbeat every minute
+   *  2. Backend returns slots where status is NotStarted or Deferred
+   *     AND scheduled_at <= now
+   *  3. Plugin selects highest-priority slot (if any)
+   *  4. For remaining slots, plugin sets status = Deferred + priority += 1
+   *
+   * @returns CalendarHeartbeatResponse or null if the backend is unreachable
+   */
+  async heartbeat(): Promise<CalendarHeartbeatResponse | null> {
+    const url = `${this.baseUrl}/calendar/agent/heartbeat`;
+    const body: CalendarHeartbeatRequest = {
+      claw_identifier: this.config.clawIdentifier,
+      agent_id: this.config.agentId,
+    };
+
+    try {
+      const response = await this.fetchJson<CalendarHeartbeatResponse>(url, {
+        method: 'GET',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Agent-ID': this.config.agentId,
+          'X-Claw-Identifier': this.config.clawIdentifier,
+        },
+        body: JSON.stringify(body),
+      });
+      return response;
+    } catch (err) {
+      // Non-fatal: backend unreachable — return null, plugin continues
+      return null;
+    }
+  }
+
+  /**
+   * Update a real (materialized) slot's status after agent execution.
+   *
+   * Used by the plugin to report:
+   *   - Slot attended (attended=true, started_at=now, status=Ongoing)
+   *   - Slot finished (actual_duration set, status=Finished)
+   *   - Slot deferred (status=Deferred, priority += 1)
+   *   - Slot aborted (status=Aborted)
+   *
+   * @param slotId  Real slot DB id
+   * @param update  Status update payload
+   * @returns true on success, false on failure
+   */
+  async updateSlot(slotId: number, update: SlotAgentUpdate): Promise<boolean> {
+    const url = `${this.baseUrl}/calendar/slots/${slotId}/agent-update`;
+    return this.postBoolean(url, update);
+  }
+
+  /**
+   * Update a virtual (plan-generated) slot's status after agent execution.
+   *
+   * When updating a virtual slot, the backend first materializes it
+   * (creates a real TimeSlot row), then applies the update.
+   * The returned slot will have a real id on subsequent calls.
+   *
+   * @param virtualId  Virtual slot id in format "plan-{plan_id}-{date}"
+   * @param update     Status update payload
+   * @returns Updated CalendarSlotResponse on success, null on failure
+   */
+  async updateVirtualSlot(
+    virtualId: string,
+    update: SlotAgentUpdate
+  ): Promise<CalendarSlotResponse | null> {
+    const url = `${this.baseUrl}/calendar/slots/virtual/${encodeURIComponent(virtualId)}/agent-update`;
+    try {
+      const response = await this.fetchJson<{ slot: CalendarSlotResponse }>(url, {
+        method: 'PATCH',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Agent-ID': this.config.agentId,
+          'X-Claw-Identifier': this.config.clawIdentifier,
+        },
+        body: JSON.stringify(update),
+      });
+      return response?.slot ?? null;
+    } catch {
+      return null;
+    }
+  }
+
+  /**
+   * Report the agent's current runtime status to HarborForge.
+   *
+   * Used to push agent status transitions:
+   *   idle → busy / on_call  (when starting a slot)
+   *   busy / on_call → idle  (when finishing a slot)
+   *   → exhausted (on rate-limit / billing error, with recovery_at)
+   *   → offline (after 2 min with no heartbeat)
+   *
+   * @param status  New agent status
+   * @param recoveryAt  ISO timestamp for expected Exhausted recovery (optional)
+   * @param exhaustReason "rate_limit" | "billing" (required if status=exhausted)
+   */
+  async reportAgentStatus(params: {
+    status: 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline';
+    recoveryAt?: string;
+    exhaustReason?: 'rate_limit' | 'billing';
+  }): Promise<boolean> {
+    const url = `${this.baseUrl}/calendar/agent/status`;
+    const body = {
+      agent_id: this.config.agentId,
+      claw_identifier: this.config.clawIdentifier,
+      ...params,
+    };
+    return this.postBoolean(url, body);
+  }
+
+  // -------------------------------------------------------------------------
+  // Internal helpers
+  // -------------------------------------------------------------------------
+
+  private async fetchJson<T>(
+    url: string,
+    init: RequestInit
+  ): Promise<T | null> {
+    const controller = new AbortController();
+    const timeout = setTimeout(() => controller.abort(), this.timeoutMs);
+
+    try {
+      const response = await fetch(url, {
+        ...init,
+        signal: controller.signal,
+      });
+      clearTimeout(timeout);
+
+      if (!response.ok) return null;
+      return (await response.json()) as T;
+    } catch {
+      clearTimeout(timeout);
+      return null;
+    }
+  }
+
+  private async postBoolean(url: string, body: unknown): Promise<boolean> {
+    const controller = new AbortController();
+    const timeout = setTimeout(() => controller.abort(), this.timeoutMs);
+
+    try {
+      const response = await fetch(url, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          'X-Agent-ID': this.config.agentId,
+          'X-Claw-Identifier': this.config.clawIdentifier,
+        },
+        body: JSON.stringify(body),
+        signal: controller.signal,
+      });
+      clearTimeout(timeout);
+      return response.ok;
+    } catch {
+      clearTimeout(timeout);
+      return false;
+    }
+  }
+}
+
+// ---------------------------------------------------------------------------
+// Utility: build CalendarBridgeConfig from plugin API context
+// ---------------------------------------------------------------------------
+
+import { hostname } from 'os';
+import { getLivePluginConfig, type HarborForgeMonitorConfig } from '../core/live-config';
+
+export interface CalendarPluginConfig {
+  /** Backend URL for calendar API (overrides monitor backendUrl) */
+  calendarBackendUrl?: string;
+  /** Server identifier (overrides auto-detected hostname) */
+  identifier?: string;
+  /** Agent ID from OpenClaw ($AGENT_ID) */
+  agentId: string;
+  /** HTTP timeout for calendar API calls (default: 5000) */
+  timeoutMs?: number;
+}
+
+/**
+ * Build a CalendarBridgeClient from the OpenClaw plugin API context.
+ *
+ * @param api           OpenClaw plugin API (register() receives this)
+ * @param fallbackUrl   Fallback backend URL if not configured
+ * @param agentId       $AGENT_ID from OpenClaw environment
+ */
+export function createCalendarBridgeClient(
+  api: { config?: Record<string, unknown>; logger?: { debug?: (...args: unknown[]) => void } },
+  fallbackUrl: string,
+  agentId: string
+): CalendarBridgeClient {
+  const baseConfig = getLivePluginConfig(api, {
+    backendUrl: fallbackUrl,
+    identifier: hostname(),
+  } as HarborForgeMonitorConfig) as HarborForgeMonitorConfig;
+
+  const clawIdentifier = baseConfig.identifier || hostname();
+
+  return new CalendarBridgeClient({
+    backendUrl: baseConfig.backendUrl || fallbackUrl,
+    clawIdentifier,
+    agentId,
+    timeoutMs: 5000,
+  });
+}
diff --git a/plugin/calendar/index.d.ts b/plugin/calendar/index.d.ts
new file mode 100644
index 0000000..7207fc6
--- /dev/null
+++ b/plugin/calendar/index.d.ts
@@ -0,0 +1,23 @@
+/**
+ * HarborForge Calendar — Plugin Module
+ *
+ * PLG-CAL-001: Calendar heartbeat request/response format definition.
+ *
+ * Exports:
+ *   • Types for heartbeat request/response and slot update
+ *   • CalendarBridgeClient — HTTP client for backend communication
+ *   • createCalendarBridgeClient — factory from plugin API context
+ *
+ * Usage in plugin/index.ts:
+ *   import { createCalendarBridgeClient } from './calendar';
+ *
+ *   const agentId = process.env.AGENT_ID || 'unknown';
+ *   const calendar = createCalendarBridgeClient(api, 'https://monitor.hangman-lab.top', agentId);
+ *
+ *   // Inside gateway_start or heartbeat tick:
+ *   const result = await calendar.heartbeat();
+ *   if (result?.slots.length) { /* handle pending slots /\ }
+ */
+export * from './types';
+export * from './calendar-bridge';
+//# sourceMappingURL=index.d.ts.map
\ No newline at end of file
diff --git a/plugin/calendar/index.d.ts.map b/plugin/calendar/index.d.ts.map
new file mode 100644
index 0000000..5762871
--- /dev/null
+++ b/plugin/calendar/index.d.ts.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.d.ts","sourceRoot":"","sources":["index.ts"],"names":[],"mappings":"AAAA;;;;;;;;;;;;;;;;;;;GAmBG;AAEH,cAAc,SAAS,CAAC;AACxB,cAAc,mBAAmB,CAAC"}
\ No newline at end of file
diff --git a/plugin/calendar/index.js b/plugin/calendar/index.js
new file mode 100644
index 0000000..a67b291
--- /dev/null
+++ b/plugin/calendar/index.js
@@ -0,0 +1,39 @@
+"use strict";
+/**
+ * HarborForge Calendar — Plugin Module
+ *
+ * PLG-CAL-001: Calendar heartbeat request/response format definition.
+ *
+ * Exports:
+ *   • Types for heartbeat request/response and slot update
+ *   • CalendarBridgeClient — HTTP client for backend communication
+ *   • createCalendarBridgeClient — factory from plugin API context
+ *
+ * Usage in plugin/index.ts:
+ *   import { createCalendarBridgeClient } from './calendar';
+ *
+ *   const agentId = process.env.AGENT_ID || 'unknown';
+ *   const calendar = createCalendarBridgeClient(api, 'https://monitor.hangman-lab.top', agentId);
+ *
+ *   // Inside gateway_start or heartbeat tick:
+ *   const result = await calendar.heartbeat();
+ *   if (result?.slots.length) { /* handle pending slots /\ }
+ */
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __exportStar = (this && this.__exportStar) || function(m, exports) {
+    for (var p in m) if (p !== "default" && !Object.prototype.hasOwnProperty.call(exports, p)) __createBinding(exports, m, p);
+};
+Object.defineProperty(exports, "__esModule", { value: true });
+__exportStar(require("./types"), exports);
+__exportStar(require("./calendar-bridge"), exports);
+//# sourceMappingURL=index.js.map
\ No newline at end of file
diff --git a/plugin/calendar/index.js.map b/plugin/calendar/index.js.map
new file mode 100644
index 0000000..88da539
--- /dev/null
+++ b/plugin/calendar/index.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"index.js","sourceRoot":"","sources":["index.ts"],"names":[],"mappings":";AAAA;;;;;;;;;;;;;;;;;;;GAmBG;;;;;;;;;;;;;;;;AAEH,0CAAwB;AACxB,oDAAkC"}
\ No newline at end of file
diff --git a/plugin/calendar/index.ts b/plugin/calendar/index.ts
new file mode 100644
index 0000000..e25866a
--- /dev/null
+++ b/plugin/calendar/index.ts
@@ -0,0 +1,23 @@
+/**
+ * HarborForge Calendar — Plugin Module
+ *
+ * PLG-CAL-001: Calendar heartbeat request/response format definition.
+ *
+ * Exports:
+ *   • Types for heartbeat request/response and slot update
+ *   • CalendarBridgeClient — HTTP client for backend communication
+ *   • createCalendarBridgeClient — factory from plugin API context
+ *
+ * Usage in plugin/index.ts:
+ *   import { createCalendarBridgeClient } from './calendar';
+ *
+ *   const agentId = process.env.AGENT_ID || 'unknown';
+ *   const calendar = createCalendarBridgeClient(api, 'https://monitor.hangman-lab.top', agentId);
+ *
+ *   // Inside gateway_start or heartbeat tick:
+ *   const result = await calendar.heartbeat();
+ *   if (result?.slots.length) { /* handle pending slots /\ }
+ */
+
+export * from './types';
+export * from './calendar-bridge';
diff --git a/plugin/calendar/types.d.ts b/plugin/calendar/types.d.ts
new file mode 100644
index 0000000..4e19b4a
--- /dev/null
+++ b/plugin/calendar/types.d.ts
@@ -0,0 +1,171 @@
+/**
+ * HarborForge Calendar — Plugin-side type definitions
+ *
+ * PLG-CAL-001: Define the Calendar heartbeat request/response format
+ * between the OpenClaw plugin and HarborForge backend.
+ *
+ * Request flow (plugin → backend):
+ *   POST /calendar/agent/heartbeat
+ *   Headers:
+ *     X-Agent-ID: <agent_id>          — OpenClaw $AGENT_ID of the calling agent
+ *     X-Claw-Identifier: <identifier> — HarborForge server identifier
+ *   Body (JSON):
+ *     { "claw_identifier": "...", "agent_id": "..." }
+ *
+ * Response flow (backend → plugin):
+ *   Returns list of TimeSlots pending execution for today.
+ *   The plugin uses slot.id / slot.virtual_id to update slot status
+ *   via subsequent API calls.
+ *
+ * References:
+ *   • NEXT_WAVE_DEV_DIRECTION.md §6 (Agent wakeup mechanism)
+ *   • HarborForge.Backend/app/models/calendar.py  — TimeSlot DB model
+ *   • HarborForge.Backend/app/schemas/calendar.py — TimeSlot schemas
+ *   • HarborForge.Backend/app/services/agent_heartbeat.py — BE-AGT-001
+ */
+/** Slot type — mirrors backend SlotType enum */
+export declare enum SlotType {
+    WORK = "work",
+    ON_CALL = "on_call",
+    ENTERTAINMENT = "entertainment",
+    SYSTEM = "system"
+}
+/** Slot lifecycle status — mirrors backend SlotStatus enum */
+export declare enum SlotStatus {
+    NOT_STARTED = "not_started",
+    ONGOING = "ongoing",
+    DEFERRED = "deferred",
+    SKIPPED = "skipped",
+    PAUSED = "paused",
+    FINISHED = "finished",
+    ABORTED = "aborted"
+}
+/** High-level event category — mirrors backend EventType enum */
+export declare enum EventType {
+    JOB = "job",
+    ENTERTAINMENT = "entertainment",
+    SYSTEM_EVENT = "system_event"
+}
+/**
+ * Calendar heartbeat request body sent by the plugin to HarborForge backend.
+ *
+ * How claw_identifier is determined:
+ *   1. Read from plugin config: `config.backendUrl` is the base URL.
+ *   2. If not set, fall back to `os.hostname()` (plugin machine hostname).
+ *
+ * How agent_id is determined:
+ *   - Read from OpenClaw environment variable: `process.env.AGENT_ID`
+ *   - This is set by OpenClaw at agent startup and uniquely identifies
+ *     the running agent instance within a single OpenClaw gateway.
+ */
+export interface CalendarHeartbeatRequest {
+    /** HarborForge server/claw identifier (matches MonitoredServer.identifier) */
+    claw_identifier: string;
+    /** OpenClaw agent ID ($AGENT_ID) for this agent session */
+    agent_id: string;
+}
+/**
+ * A single calendar slot returned in the heartbeat response.
+ *
+ * For **real** (materialized) slots: `id` is set, `virtual_id` is null.
+ * For **virtual** (plan-generated) slots: `id` is null, `virtual_id`
+ * is the `plan-{plan_id}-{date}` identifier.
+ *
+ * Key fields the plugin uses:
+ *   - `id` / `virtual_id`  — to update slot status after execution
+ *   - `event_type`          — to determine what action to take
+ *   - `event_data`          — job details / system event type
+ *   - `slot_type`           — work vs on_call (affects agent status transition)
+ *   - `scheduled_at`        — planned start time (HH:MM:SS)
+ *   - `estimated_duration`  — expected minutes (for time-tracking)
+ *   - `priority`            — for multi-slot competition logic
+ *   - `status`              — current status (NotStarted / Deferred)
+ */
+export interface CalendarSlotResponse {
+    /** Real slot DB id. Null for virtual slots. */
+    id: number | null;
+    /** Virtual slot id (plan-{plan_id}-{date}). Null for real slots. */
+    virtual_id: string | null;
+    /** Owner user id */
+    user_id: number;
+    /** Calendar date */
+    date: string;
+    /** Slot type */
+    slot_type: SlotType;
+    /** Estimated duration in minutes (1-50) */
+    estimated_duration: number;
+    /** Planned start time (ISO time string: "HH:MM:SS") */
+    scheduled_at: string;
+    /** Actual start time, set when slot begins (null until started) */
+    started_at: string | null;
+    /** Whether the slot has been attended */
+    attended: boolean;
+    /** Actual duration in minutes (set when slot finishes) */
+    actual_duration: number | null;
+    /** Event category */
+    event_type: EventType | null;
+    /** Event details JSON — structure depends on event_type (see below) */
+    event_data: CalendarEventData | null;
+    /** Priority 0-99, higher = more urgent */
+    priority: number;
+    /** Current lifecycle status */
+    status: SlotStatus;
+    /** Source plan id if materialized from a SchedulePlan; null otherwise */
+    plan_id: number | null;
+}
+/**
+ * Event data stored inside CalendarSlotResponse.event_data.
+ * The shape depends on event_type.
+ *
+ * When event_type == "job":
+ *   { "type": "Task|Support|Meeting|Essential", "code": "TASK-42", "working_sessions": ["..."] }
+ *
+ * When event_type == "system_event":
+ *   { "event": "ScheduleToday|SummaryToday|ScheduledGatewayRestart" }
+ *
+ * When event_type == "entertainment":
+ *   { /* TBD /\ }
+ */
+export interface CalendarEventDataJob {
+    type: 'Task' | 'Support' | 'Meeting' | 'Essential';
+    code: string;
+    working_sessions?: string[];
+}
+export interface CalendarEventDataSystemEvent {
+    event: 'ScheduleToday' | 'SummaryToday' | 'ScheduledGatewayRestart';
+}
+export type CalendarEventData = CalendarEventDataJob | CalendarEventDataSystemEvent | Record<string, any>;
+/**
+ * Full heartbeat response returned by GET /calendar/agent/heartbeat
+ *
+ * Fields:
+ *   slots    — list of pending TimeSlots for today (sorted by priority desc)
+ *   agent_status — current agent status from the backend's perspective
+ *                  (idle | on_call | busy | exhausted | offline)
+ */
+export interface CalendarHeartbeatResponse {
+    /** Pending slots for today — sorted by priority descending */
+    slots: CalendarSlotResponse[];
+    /** Current agent status in HarborForge */
+    agent_status: AgentStatusValue;
+    /** Human-readable message (optional) */
+    message?: string;
+}
+/** Agent status values — mirrors backend AgentStatus enum */
+export type AgentStatusValue = 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline';
+/**
+ * Request body for updating a real slot's status after agent execution.
+ * Called by the plugin after attending / finishing / deferring a slot.
+ *
+ * Endpoint: PATCH /calendar/slots/{slot_id}/agent-update
+ * (Plugin-facing variant that bypasses some user-level guards)
+ */
+export interface SlotAgentUpdate {
+    /** New status to set */
+    status: SlotStatus;
+    /** Actual start time (ISO time string HH:MM:SS), required when attending */
+    started_at?: string;
+    /** Actual duration in minutes, set when finishing */
+    actual_duration?: number;
+}
+//# sourceMappingURL=types.d.ts.map
\ No newline at end of file
diff --git a/plugin/calendar/types.d.ts.map b/plugin/calendar/types.d.ts.map
new file mode 100644
index 0000000..2866d75
--- /dev/null
+++ b/plugin/calendar/types.d.ts.map
@@ -0,0 +1 @@
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\ No newline at end of file
diff --git a/plugin/calendar/types.js b/plugin/calendar/types.js
new file mode 100644
index 0000000..2fefa40
--- /dev/null
+++ b/plugin/calendar/types.js
@@ -0,0 +1,58 @@
+"use strict";
+/**
+ * HarborForge Calendar — Plugin-side type definitions
+ *
+ * PLG-CAL-001: Define the Calendar heartbeat request/response format
+ * between the OpenClaw plugin and HarborForge backend.
+ *
+ * Request flow (plugin → backend):
+ *   POST /calendar/agent/heartbeat
+ *   Headers:
+ *     X-Agent-ID: <agent_id>          — OpenClaw $AGENT_ID of the calling agent
+ *     X-Claw-Identifier: <identifier> — HarborForge server identifier
+ *   Body (JSON):
+ *     { "claw_identifier": "...", "agent_id": "..." }
+ *
+ * Response flow (backend → plugin):
+ *   Returns list of TimeSlots pending execution for today.
+ *   The plugin uses slot.id / slot.virtual_id to update slot status
+ *   via subsequent API calls.
+ *
+ * References:
+ *   • NEXT_WAVE_DEV_DIRECTION.md §6 (Agent wakeup mechanism)
+ *   • HarborForge.Backend/app/models/calendar.py  — TimeSlot DB model
+ *   • HarborForge.Backend/app/schemas/calendar.py — TimeSlot schemas
+ *   • HarborForge.Backend/app/services/agent_heartbeat.py — BE-AGT-001
+ */
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.EventType = exports.SlotStatus = exports.SlotType = void 0;
+// ---------------------------------------------------------------------------
+// Enums (mirror backend enums)
+// ---------------------------------------------------------------------------
+/** Slot type — mirrors backend SlotType enum */
+var SlotType;
+(function (SlotType) {
+    SlotType["WORK"] = "work";
+    SlotType["ON_CALL"] = "on_call";
+    SlotType["ENTERTAINMENT"] = "entertainment";
+    SlotType["SYSTEM"] = "system";
+})(SlotType || (exports.SlotType = SlotType = {}));
+/** Slot lifecycle status — mirrors backend SlotStatus enum */
+var SlotStatus;
+(function (SlotStatus) {
+    SlotStatus["NOT_STARTED"] = "not_started";
+    SlotStatus["ONGOING"] = "ongoing";
+    SlotStatus["DEFERRED"] = "deferred";
+    SlotStatus["SKIPPED"] = "skipped";
+    SlotStatus["PAUSED"] = "paused";
+    SlotStatus["FINISHED"] = "finished";
+    SlotStatus["ABORTED"] = "aborted";
+})(SlotStatus || (exports.SlotStatus = SlotStatus = {}));
+/** High-level event category — mirrors backend EventType enum */
+var EventType;
+(function (EventType) {
+    EventType["JOB"] = "job";
+    EventType["ENTERTAINMENT"] = "entertainment";
+    EventType["SYSTEM_EVENT"] = "system_event";
+})(EventType || (exports.EventType = EventType = {}));
+//# sourceMappingURL=types.js.map
\ No newline at end of file
diff --git a/plugin/calendar/types.js.map b/plugin/calendar/types.js.map
new file mode 100644
index 0000000..5c04e3e
--- /dev/null
+++ b/plugin/calendar/types.js.map
@@ -0,0 +1 @@
+{"version":3,"file":"types.js","sourceRoot":"","sources":["types.ts"],"names":[],"mappings":";AAAA;;;;;;;;;;;;;;;;;;;;;;;;GAwBG;;;AAEH,8EAA8E;AAC9E,+BAA+B;AAC/B,8EAA8E;AAE9E,gDAAgD;AAChD,IAAY,QAKX;AALD,WAAY,QAAQ;IAClB,yBAAa,CAAA;IACb,+BAAmB,CAAA;IACnB,2CAA+B,CAAA;IAC/B,6BAAiB,CAAA;AACnB,CAAC,EALW,QAAQ,wBAAR,QAAQ,QAKnB;AAED,8DAA8D;AAC9D,IAAY,UAQX;AARD,WAAY,UAAU;IACpB,yCAA2B,CAAA;IAC3B,iCAAmB,CAAA;IACnB,mCAAqB,CAAA;IACrB,iCAAmB,CAAA;IACnB,+BAAiB,CAAA;IACjB,mCAAqB,CAAA;IACrB,iCAAmB,CAAA;AACrB,CAAC,EARW,UAAU,0BAAV,UAAU,QAQrB;AAED,iEAAiE;AACjE,IAAY,SAIX;AAJD,WAAY,SAAS;IACnB,wBAAW,CAAA;IACX,4CAA+B,CAAA;IAC/B,0CAA6B,CAAA;AAC/B,CAAC,EAJW,SAAS,yBAAT,SAAS,QAIpB"}
\ No newline at end of file
diff --git a/plugin/calendar/types.ts b/plugin/calendar/types.ts
new file mode 100644
index 0000000..90f424e
--- /dev/null
+++ b/plugin/calendar/types.ts
@@ -0,0 +1,198 @@
+/**
+ * HarborForge Calendar — Plugin-side type definitions
+ *
+ * PLG-CAL-001: Define the Calendar heartbeat request/response format
+ * between the OpenClaw plugin and HarborForge backend.
+ *
+ * Request flow (plugin → backend):
+ *   POST /calendar/agent/heartbeat
+ *   Headers:
+ *     X-Agent-ID: <agent_id>          — OpenClaw $AGENT_ID of the calling agent
+ *     X-Claw-Identifier: <identifier> — HarborForge server identifier
+ *   Body (JSON):
+ *     { "claw_identifier": "...", "agent_id": "..." }
+ *
+ * Response flow (backend → plugin):
+ *   Returns list of TimeSlots pending execution for today.
+ *   The plugin uses slot.id / slot.virtual_id to update slot status
+ *   via subsequent API calls.
+ *
+ * References:
+ *   • NEXT_WAVE_DEV_DIRECTION.md §6 (Agent wakeup mechanism)
+ *   • HarborForge.Backend/app/models/calendar.py  — TimeSlot DB model
+ *   • HarborForge.Backend/app/schemas/calendar.py — TimeSlot schemas
+ *   • HarborForge.Backend/app/services/agent_heartbeat.py — BE-AGT-001
+ */
+
+// ---------------------------------------------------------------------------
+// Enums (mirror backend enums)
+// ---------------------------------------------------------------------------
+
+/** Slot type — mirrors backend SlotType enum */
+export enum SlotType {
+  WORK = 'work',
+  ON_CALL = 'on_call',
+  ENTERTAINMENT = 'entertainment',
+  SYSTEM = 'system',
+}
+
+/** Slot lifecycle status — mirrors backend SlotStatus enum */
+export enum SlotStatus {
+  NOT_STARTED = 'not_started',
+  ONGOING = 'ongoing',
+  DEFERRED = 'deferred',
+  SKIPPED = 'skipped',
+  PAUSED = 'paused',
+  FINISHED = 'finished',
+  ABORTED = 'aborted',
+}
+
+/** High-level event category — mirrors backend EventType enum */
+export enum EventType {
+  JOB = 'job',
+  ENTERTAINMENT = 'entertainment',
+  SYSTEM_EVENT = 'system_event',
+}
+
+// ---------------------------------------------------------------------------
+// Request types
+// ---------------------------------------------------------------------------
+
+/**
+ * Calendar heartbeat request body sent by the plugin to HarborForge backend.
+ *
+ * How claw_identifier is determined:
+ *   1. Read from plugin config: `config.backendUrl` is the base URL.
+ *   2. If not set, fall back to `os.hostname()` (plugin machine hostname).
+ *
+ * How agent_id is determined:
+ *   - Read from OpenClaw environment variable: `process.env.AGENT_ID`
+ *   - This is set by OpenClaw at agent startup and uniquely identifies
+ *     the running agent instance within a single OpenClaw gateway.
+ */
+export interface CalendarHeartbeatRequest {
+  /** HarborForge server/claw identifier (matches MonitoredServer.identifier) */
+  claw_identifier: string;
+  /** OpenClaw agent ID ($AGENT_ID) for this agent session */
+  agent_id: string;
+}
+
+// ---------------------------------------------------------------------------
+// Response types
+// ---------------------------------------------------------------------------
+
+/**
+ * A single calendar slot returned in the heartbeat response.
+ *
+ * For **real** (materialized) slots: `id` is set, `virtual_id` is null.
+ * For **virtual** (plan-generated) slots: `id` is null, `virtual_id`
+ * is the `plan-{plan_id}-{date}` identifier.
+ *
+ * Key fields the plugin uses:
+ *   - `id` / `virtual_id`  — to update slot status after execution
+ *   - `event_type`          — to determine what action to take
+ *   - `event_data`          — job details / system event type
+ *   - `slot_type`           — work vs on_call (affects agent status transition)
+ *   - `scheduled_at`        — planned start time (HH:MM:SS)
+ *   - `estimated_duration`  — expected minutes (for time-tracking)
+ *   - `priority`            — for multi-slot competition logic
+ *   - `status`              — current status (NotStarted / Deferred)
+ */
+export interface CalendarSlotResponse {
+  /** Real slot DB id. Null for virtual slots. */
+  id: number | null;
+  /** Virtual slot id (plan-{plan_id}-{date}). Null for real slots. */
+  virtual_id: string | null;
+  /** Owner user id */
+  user_id: number;
+  /** Calendar date */
+  date: string; // ISO date string: "YYYY-MM-DD"
+  /** Slot type */
+  slot_type: SlotType;
+  /** Estimated duration in minutes (1-50) */
+  estimated_duration: number;
+  /** Planned start time (ISO time string: "HH:MM:SS") */
+  scheduled_at: string;
+  /** Actual start time, set when slot begins (null until started) */
+  started_at: string | null;
+  /** Whether the slot has been attended */
+  attended: boolean;
+  /** Actual duration in minutes (set when slot finishes) */
+  actual_duration: number | null;
+  /** Event category */
+  event_type: EventType | null;
+  /** Event details JSON — structure depends on event_type (see below) */
+  event_data: CalendarEventData | null;
+  /** Priority 0-99, higher = more urgent */
+  priority: number;
+  /** Current lifecycle status */
+  status: SlotStatus;
+  /** Source plan id if materialized from a SchedulePlan; null otherwise */
+  plan_id: number | null;
+}
+
+/**
+ * Event data stored inside CalendarSlotResponse.event_data.
+ * The shape depends on event_type.
+ *
+ * When event_type == "job":
+ *   { "type": "Task|Support|Meeting|Essential", "code": "TASK-42", "working_sessions": ["..."] }
+ *
+ * When event_type == "system_event":
+ *   { "event": "ScheduleToday|SummaryToday|ScheduledGatewayRestart" }
+ *
+ * When event_type == "entertainment":
+ *   { /* TBD /\ }
+ */
+export interface CalendarEventDataJob {
+  type: 'Task' | 'Support' | 'Meeting' | 'Essential';
+  code: string;
+  working_sessions?: string[];
+}
+
+export interface CalendarEventDataSystemEvent {
+  event: 'ScheduleToday' | 'SummaryToday' | 'ScheduledGatewayRestart';
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export type CalendarEventData = CalendarEventDataJob | CalendarEventDataSystemEvent | Record<string, any>;
+
+/**
+ * Full heartbeat response returned by GET /calendar/agent/heartbeat
+ *
+ * Fields:
+ *   slots    — list of pending TimeSlots for today (sorted by priority desc)
+ *   agent_status — current agent status from the backend's perspective
+ *                  (idle | on_call | busy | exhausted | offline)
+ */
+export interface CalendarHeartbeatResponse {
+  /** Pending slots for today — sorted by priority descending */
+  slots: CalendarSlotResponse[];
+  /** Current agent status in HarborForge */
+  agent_status: AgentStatusValue;
+  /** Human-readable message (optional) */
+  message?: string;
+}
+
+/** Agent status values — mirrors backend AgentStatus enum */
+export type AgentStatusValue = 'idle' | 'on_call' | 'busy' | 'exhausted' | 'offline';
+
+// ---------------------------------------------------------------------------
+// Slot update types (for post-execution status updates)
+// ---------------------------------------------------------------------------
+
+/**
+ * Request body for updating a real slot's status after agent execution.
+ * Called by the plugin after attending / finishing / deferring a slot.
+ *
+ * Endpoint: PATCH /calendar/slots/{slot_id}/agent-update
+ * (Plugin-facing variant that bypasses some user-level guards)
+ */
+export interface SlotAgentUpdate {
+  /** New status to set */
+  status: SlotStatus;
+  /** Actual start time (ISO time string HH:MM:SS), required when attending */
+  started_at?: string;
+  /** Actual duration in minutes, set when finishing */
+  actual_duration?: number;
+}
diff --git a/plugin/openclaw.plugin.json b/plugin/openclaw.plugin.json
index fe9fbc9..30a3e60 100644
--- a/plugin/openclaw.plugin.json
+++ b/plugin/openclaw.plugin.json
@@ -8,43 +8,57 @@
     "type": "object",
     "additionalProperties": false,
     "properties": {
-      "enabled": { 
-        "type": "boolean", 
+      "enabled": {
+        "type": "boolean",
         "default": true,
         "description": "Enable the HarborForge plugin"
       },
-      "backendUrl": { 
-        "type": "string", 
+      "backendUrl": {
+        "type": "string",
         "default": "https://monitor.hangman-lab.top",
-        "description": "HarborForge Monitor backend URL"
+        "description": "HarborForge backend base URL (shared by Monitor and Calendar API)"
       },
-      "identifier": { 
+      "identifier": {
         "type": "string",
-        "description": "Server identifier (auto-detected from hostname if not set)"
+        "description": "Server/claw identifier. Used as claw_identifier in Calendar heartbeat and as MonitoredServer.identifier. Auto-detected from hostname if not set."
       },
-      "apiKey": { 
+      "apiKey": {
         "type": "string",
-        "description": "API Key from HarborForge Monitor admin panel (optional but required for authentication)"
+        "description": "API Key from HarborForge Monitor admin panel (optional but required for Monitor authentication)"
       },
       "monitor_port": {
         "type": "number",
         "description": "Local port for communication between HarborForge Monitor and this plugin"
       },
-      "reportIntervalSec": { 
-        "type": "number", 
+      "reportIntervalSec": {
+        "type": "number",
         "default": 30,
         "description": "How often to report metrics (seconds)"
       },
-      "httpFallbackIntervalSec": { 
-        "type": "number", 
+      "httpFallbackIntervalSec": {
+        "type": "number",
         "default": 60,
         "description": "HTTP heartbeat interval when WS unavailable"
       },
-      "logLevel": { 
-        "type": "string", 
-        "enum": ["debug", "info", "warn", "error"], 
+      "logLevel": {
+        "type": "string",
+        "enum": ["debug", "info", "warn", "error"],
         "default": "info",
         "description": "Logging level"
+      },
+      "calendarEnabled": {
+        "type": "boolean",
+        "default": true,
+        "description": "Enable Calendar heartbeat integration (PLG-CAL-001). When enabled, plugin sends periodic heartbeat to /calendar/agent/heartbeat to receive pending TimeSlots."
+      },
+      "calendarHeartbeatIntervalSec": {
+        "type": "number",
+        "default": 60,
+        "description": "How often to send Calendar heartbeat to backend (seconds). Defaults to 60s (1 minute)."
+      },
+      "calendarApiKey": {
+        "type": "string",
+        "description": "API key for Calendar API authentication. If not set, uses apiKey or plugin auto-authentication via X-Agent-ID header."
       }
     }
   }