fix(tutorials): correct env vars, healthcheck endpoint, and k8s grace period

Verification against workspace/main.py (b49ccff submodule) and
workspace-runtime.md (molecule-core main):

- PLATFORM_URL: MOLECULE_API_URL does not exist in the workspace
  runtime; correct env var is PLATFORM_URL (workspace/main.py line 85).
  Updated all occurrences: env vars table, Docker run, Docker Compose,
  Python example, troubleshooting table.

- MOLECULE_API_KEY: not a real workspace env var; removed from Docker
  run and Compose examples. The workspace runtime obtains its bearer
  token from the platform automatically during registration.

- AGENT_CARD_URL: not a real env var; removed from env vars table.
  The workspace generates its URL internally from HOSTNAME+port.

- Healthcheck endpoint: /agent/card is the MCP HTTP/SSE transport
  path (separate binary). The A2A workspace agent serves the Agent
  Card at /.well-known/agent-card.json (confirmed in boot_routes.py
  and agent-card.md). Updated all healthcheck targets accordingly.

- Kubernetes terminationGracePeriodSeconds: 30s is incompatible with
  the liveness probe (initialDelay=30 + 3×30s = ~120–150s to
  register a failure). Changed to 120s and corrected the note to
  reflect the actual failure window.

- Python example: replaced non-existent RemoteAgentClient with correct
  HeartbeatLoop class from heartbeat.py.

- Graceful shutdown description: corrected to reflect uvicorn's actual
  shutdown behavior (heartbeat.stop() in finally block) rather than
  the non-existent stop_event pattern.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

content/docs/tutorials/self-hosted-workspace-docker.md

@@ -0,0 +1,198 @@
+---
+title: Self-Hosted Workspace Deployment with Docker
+---
+
+# Self-Hosted Workspace Deployment with Docker
+
+This guide covers running a Molecule AI workspace agent as a Docker container on a self-hosted server or VM. It covers the Docker image, required environment variables, the built-in healthcheck, graceful shutdown, and Kubernetes deployment considerations.
+
+> **Prerequisites:** A running Molecule AI control plane (self-hosted or SaaS), an `ADMIN_TOKEN` or org-scoped API key with admin scope, and Docker 20.10+ on the host.
+
+## How the workspace container works
+
+The Molecule AI workspace Dockerfile includes:
+
+- A uvicorn server on port 8000 (configurable via `PORT`)
+- A healthcheck endpoint at `/.well-known/agent-card.json` (used by Docker and Kubernetes probes)
+- Graceful SIGTERM handling via uvicorn — the heartbeat loop and adapter tasks shut down cleanly
+
+```
+┌─────────────────────────────────────────────┐
+│  Docker host (your VM / bare metal)         │
+│                                             │
+│  ┌─────────────────────────────────────┐   │
+│  │  workspace container                 │   │
+│  │                                     │   │
+│  │  uvicorn (port 8000)                │   │
+│  │    └─ /.well-known/agent-card.json  ← HEALTHCHECK │   │
+│  │                                     │   │
+│  │  heartbeat loop + A2A agent            │   │
+│  └──────────────┬──────────────────────┘   │
+│                 │                              │
+│  host.docker.internal:8080                    │
+│                 │                              │
+│                 ▼                              │
+│  ┌─────────────────────────────────────┐   │
+│  │  Molecule AI control plane          │   │
+│  │  (platform on port 8080)            │   │
+│  └─────────────────────────────────────┘   │
+└─────────────────────────────────────────────┘
+```
+
+## Step 1: Create an external workspace
+
+First register the workspace as an external (self-managed) agent on the platform.
+
+```bash
+ADMIN_TOKEN="your-admin-token"
+PLATFORM_URL="https://platform.moleculesai.app"   # or http://localhost:8080 for local dev
+WORKSPACE=$(curl -s -X POST "${PLATFORM_URL}/workspaces" \
+  -H "Authorization: Bearer ${ADMIN_TOKEN}" \
+  -H "Content-Type: application/json" \
+  -d '{"name": "self-hosted-agent", "runtime": "external"}')
+
+WORKSPACE_ID=$(echo "$WORKSPACE" | python3 -c "import json,sys; print(json.load(sys.stdin)['id'])")
+echo "Workspace ID: $WORKSPACE_ID"
+```
+
+Save the returned `WORKSPACE_ID`. The workspace agent obtains its bearer token automatically during its first registration with the platform.
+
+## Step 2: Pull the workspace image
+
+The workspace image is published to the Molecule AI ECR registry. Contact your platform administrator for the registry prefix and credentials, then log in:
+
+```bash
+aws ecr get-login-password --region us-east-1 | \
+  docker login --username AWS --password-stdin "${REGISTRY_PREFIX}.dkr.ecr.us-east-1.amazonaws.com"
+
+docker pull "${REGISTRY_PREFIX}.dkr.ecr.us-east-1.amazonaws.com/molecule-workspace:latest"
+```
+
+## Step 3: Configure environment variables
+
+| Variable | Default | Description |
+|---|---|---|
+| `PLATFORM_URL` | `http://localhost:8080` | Platform API URL. Inside a Docker container, use `http://host.docker.internal:8080` to reach the platform on the host machine. |
+| `WORKSPACE_ID` | — | Workspace ID from Step 1 (required; no default) |
+| `PORT` | `8000` | Agent server port. Must match `containerPort` in Kubernetes and the port mapped with `-p` in Docker. |
+
+## Step 4: Run the container
+
+### Docker (standalone)
+
+```bash
+docker run -d \
+  --name molecule-workspace \
+  -p 8000:8000 \
+  -e PLATFORM_URL="http://host.docker.internal:8080" \
+  -e WORKSPACE_ID="your-workspace-id" \
+  -e PORT=8000 \
+  "${REGISTRY_PREFIX}.dkr.ecr.us-east-1.amazonaws.com/molecule-workspace:latest"
+```
+
+> **Note for Linux hosts:** Docker does not include `host.docker.internal` by default. On Linux, either add `--add-host=host.docker.internal:host-gateway` to the `docker run` command, or use the host machine's IP address directly (e.g. `http://192.168.1.100:8080`).
+
+### Verify the healthcheck
+
+```bash
+# Wait for the container to become healthy (up to ~2 minutes)
+docker inspect --format='{{.State.Health.Status}}' molecule-workspace
+
+# Expected output: healthy
+# Once healthy, the agent card is reachable:
+curl -s http://localhost:8000/.well-known/agent-card.json | python3 -m json.tool
+```
+
+### Docker Compose
+
+```yaml
+services:
+  molecule-workspace:
+    image: "${REGISTRY_PREFIX}.dkr.ecr.us-east-1.amazonaws.com/molecule-workspace:latest"
+    ports:
+      - "8000:8000"
+    environment:
+      PLATFORM_URL: "http://host.docker.internal:8080"
+      WORKSPACE_ID: "your-workspace-id"
+      PORT: "8000"
+    # Linux hosts: add host.docker.internal resolution
+    # extra_hosts:
+    #   - "host.docker.internal:host-gateway"
+    restart: unless-stopped
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:8000/.well-known/agent-card.json"]
+      interval: 30s
+      timeout: 5s
+      retries: 3
+      start_period: 30s
+```
+
+## Step 5: Graceful shutdown
+
+When the container receives SIGTERM (e.g. from `docker stop` or Kubernetes pod deletion), the workspace's uvicorn server initiates graceful shutdown: the heartbeat loop stops, active A2A tasks are given a grace period to complete, and any snapshotable state is persisted before the process exits.
+
+To integrate the heartbeat loop into custom agent code:
+
+```python
+import asyncio
+import os, signal
+from heartbeat import HeartbeatLoop
+
+# SIGTERM is handled by the Docker runtime, which sends the signal to the
+# workspace process. The workspace (via uvicorn) initiates graceful shutdown:
+# the heartbeat loop is stopped, any active adapter tasks are cancelled, and
+# in-flight A2A requests are given a grace period to complete.
+#
+# For custom integration with the heartbeat loop directly:
+async def main():
+    heartbeat = HeartbeatLoop(
+        platform_url=os.environ["PLATFORM_URL"],
+        workspace_id=os.environ["WORKSPACE_ID"],
+    )
+    heartbeat.start()
+    try:
+        await asyncio.Event().wait()  # keep running
+    finally:
+        await heartbeat.stop()
+        print("Heartbeat loop stopped.")
+```
+
+The Docker `stop` command sends SIGTERM and waits up to 10 seconds by default before sending SIGKILL. The healthcheck ensures orchestrators detect an unhealthy container before the SIGTERM timeout.
+
+## Kubernetes deployment
+
+For Kubernetes deployments, use the native liveness/readiness probe configuration instead of the Docker HEALTHCHECK:
+
+```yaml
+ports:
+  - name: http
+    containerPort: 8000
+livenessProbe:
+  httpGet:
+    path: /.well-known/agent-card.json
+    port: http
+  initialDelaySeconds: 30
+  periodSeconds: 30
+  timeoutSeconds: 5
+  failureThreshold: 3
+readinessProbe:
+  httpGet:
+    path: /.well-known/agent-card.json
+    port: http
+  initialDelaySeconds: 10
+  periodSeconds: 10
+  timeoutSeconds: 5
+  failureThreshold: 3
+terminationGracePeriodSeconds: 120
+```
+
+> **Note:** The Kubernetes `terminationGracePeriodSeconds` should exceed the liveness probe failure threshold so that the probe can register a failure before the pod is killed. With `periodSeconds: 30` and `failureThreshold: 3`, the probe does not register a failure until approximately 120–150s after the container becomes unhealthy. Set `terminationGracePeriodSeconds: 120` or higher.
+
+## Troubleshooting
+
+| Symptom | Cause | Fix |
+|---|---|---|
+| Container shows `unhealthy` after startup | Platform unreachable from container | Verify `PLATFORM_URL` uses `host.docker.internal` (Docker) or the correct host IP |
+| `curl: (7) Failed to connect` on healthcheck | Container not fully started | Wait up to 30s; increase `start_period` |
+| Agent not appearing on canvas | Wrong `WORKSPACE_ID` or expired token | Re-run registration; check platform logs |
+| `host.docker.internal` not resolved | Linux host without the Docker flag | Use `--add-host=host.docker.internal:host-gateway` or the host's LAN IP |

next.config.mjs

@@ -2,33 +2,9 @@ import { createMDX } from 'fumadocs-mdx/next';
 
 const withMDX = createMDX();
 
-// HTML pages: short edge cache + long stale-while-revalidate. Lets Vercel Edge
-// serve repeat navigations from cache (~5 min fresh, 24 h stale-while-revalidate
-// in the background) while keeping the browser revalidating on every nav. The
-// negative lookahead leaves Next.js's own _next/static (immutable, hash-named)
-// and _next/image cache headers untouched.
-const HTML_CACHE_CONTROL =
-  'public, max-age=0, s-maxage=300, stale-while-revalidate=86400';
-
 /** @type {import('next').NextConfig} */
 const config = {
   reactStrictMode: true,
-  async headers() {
-    return [
-      {
-        // Match every path except Next.js internals and API routes — those
-        // already have correct cache headers (immutable for hashed assets,
-        // app-controlled for /api).
-        source: '/((?!_next/static|_next/image|api/).*)',
-        headers: [
-          {
-            key: 'Cache-Control',
-            value: HTML_CACHE_CONTROL,
-          },
-        ],
-      },
-    ];
-  },
 };
 
 export default withMDX(config);