feat: playwright browser cache mount + PLAYWRIGHT_BROWSERS_PATH; ops guide: MCP stack inherited from base image

daemon/docker.go

@@ -49,6 +49,8 @@ const (
 	authMountTarget       string = "/root/.pi/agent/auth.json"
 	envHostPiAgentDir     string = "LVMH_HOST_PI_AGENT_DIR"
 	envSecretsDir         string = "LVMH_SECRETS_DIR"
+	envCloakCacheDir      string = "LVMH_CLOAK_CACHE_DIR"
+	envPlaywrightCacheDir string = "LVMH_PLAYWRIGHT_CACHE_DIR"
 	sshMountTarget        string = "/root/.ssh"
 	gitconfigMountTarget  string = "/root/.gitconfig"
 	workspaceMount        string = "/workspace"
@@ -374,6 +376,7 @@ func workerEnv(s *Spawner, repo, sessionID string) []string {
 		"GEMINI_API_KEY=" + os.Getenv("GEMINI_API_KEY"),
 		"DEEPSEEK_KEY=" + os.Getenv("DEEPSEEK_KEY"),
 		"ANTHROPIC_API_KEY=" + os.Getenv("ANTHROPIC_API_KEY"),
+		"PLAYWRIGHT_BROWSERS_PATH=/pw-browsers",
 		envLVMHRepo + "=" + repo,
 	}
 	// Gitea token (write scope) so agents can push and open PRs.
@@ -555,6 +558,17 @@ func (s *Spawner) createAndStart(ctx context.Context, repo, slug, sessionID stri
 	if hostAgent := os.Getenv(envHostPiAgentDir); hostAgent != "" {
 		binds = append(binds, hostAgent+"/auth.json:"+authMountTarget+":ro")
 	}
+	// Shared playwright browser cache (host path, read-only); the env var
+	// below makes every playwright-based MCP use it instead of downloading.
+	if pw := os.Getenv(envPlaywrightCacheDir); pw != "" {
+		binds = append(binds, pw+":/pw-browsers:ro")
+	}
+	// Shared cloakbrowser chromium cache (host path, read-only): browsers
+	// are ~700MB; one copy serves every container. CLOAKBROWSER_CACHE_DIR
+	// points the MCP at it (see docker/mcp.json).
+	if cb := os.Getenv(envCloakCacheDir); cb != "" {
+		binds = append(binds, cb+":/cloakbrowser-cache:ro")
+	}
 	// Deploy secrets (ssh key + known_hosts + config, gitconfig), read-only.
 	// Bind sources resolve on the HOST (docker.sock semantics), so this env
 	// must carry the host path of the secrets dir.

daemon/spawner_test.go

@@ -72,7 +72,7 @@ func TestSpawnerStartHappyPath(t *testing.T) {
 	passthrough := map[string]bool{
 		"OPENAI_API_KEY": true, "GEMINI_API_KEY": true,
 		"DEEPSEEK_KEY": true, "ANTHROPIC_API_KEY": true,
-		"LVMH_GITEA_TOKEN": true,
+		"LVMH_GITEA_TOKEN": true, "PLAYWRIGHT_BROWSERS_PATH": true,
 	}
 	for _, e := range c.Env {
 		if name, _, ok := strings.Cut(e, "="); ok && passthrough[name] {

docker-compose.yml

@@ -20,6 +20,8 @@ services:
       # this must be the HOST path of the pi config (auth.json etc.).
       LVMH_HOST_PI_AGENT_DIR: ${LVMH_PI_AGENT_DIR:-/home/alarm/.dotfiles/pi/agent}
       LVMH_SECRETS_DIR: /zdata/root/lvmh-secrets
+      LVMH_CLOAK_CACHE_DIR: /home/alarm/.cloakbrowser
+      LVMH_PLAYWRIGHT_CACHE_DIR: /home/alarm/.cache/ms-playwright
       OPENAI_API_KEY: ${OPENAI_API_KEY:-}
       GEMINI_API_KEY: ${GEMINI_API_KEY:-}
       DEEPSEEK_KEY: ${DEEPSEEK_KEY:-}

docker/control.Dockerfile

@@ -8,6 +8,9 @@ RUN apt-get update \
   && apt-get install -y --no-install-recommends \
     bash ca-certificates git ripgrep curl xz-utils make jq golang-go \
     docker.io \
+    libglib2.0-0 libnss3 libnspr4 libatk1.0-0 libatk-bridge2.0-0 \
+    libcups2 libdrm2 libxkbcommon0 libxcomposite1 libxdamage1 \
+    libxfixes3 libxrandr2 libgbm1 libpango-1.0-0 libcairo2 libasound2 \
   && rm -rf /var/lib/apt/lists/*
 
 RUN npm install -g --ignore-scripts @earendil-works/pi-coding-agent
@@ -34,6 +37,11 @@ COPY docker/bridge /bridge
 COPY docker/ops-context/entrypoint.sh /entrypoint.sh
 RUN chmod +x /entrypoint.sh
 
+# MCP tooling (same as workers; ops also browses).
+RUN npm-real install -g --ignore-scripts cloakbrowser-mcp@1.4.0 \
+	&& mkdir -p /root/.config/mcp
+COPY docker/mcp.json /root/.config/mcp/mcp.json
+
 ENV PI_SESSION_DIR=/pi-sessions
 WORKDIR /ops
 ENTRYPOINT ["/entrypoint.sh"]

docker/mcp.json

@@ -0,0 +1,13 @@
+{
+  "mcpServers": {
+    "playwright": {
+      "command": "npx",
+      "args": ["@playwright/mcp@latest", "--headless", "--browser", "chromium"]
+    },
+    "cloakbrowser": {
+      "command": "cloakbrowser-mcp",
+      "args": [],
+      "env": { "CLOAKBROWSER_CACHE_DIR": "/cloakbrowser-cache" }
+    }
+  }
+}

docker/ops-context/AGENTS.md

@@ -41,7 +41,12 @@ When asked to prepare a workspace for a repo (e.g. "prepare empstream"):
 
    Include everything an agent working in that repo needs (compilers, DB
    clients, protobuf, etc.). The base already has: node 24, pi, golang, git,
-   ripgrep, make, jq, gopls. Don't reinstall those.
+   ripgrep, make, jq, gopls, **the MCP stack (cloakbrowser-mcp, playwright
+   via npx, chromium runtime libs, `/root/.config/mcp/mcp.json`)** plus
+   shared browser-cache mounts (`/cloakbrowser-cache`, `/pw-browsers`).
+   Don't reinstall any of those — `FROM lvmh-worker:latest` inherits them.
+   If a repo needs an extra MCP server, MERGE it into the image's
+   `/root/.config/mcp/mcp.json` (never overwrite the existing servers).
 
 3. **Build**:
 

docker/worker.Dockerfile

@@ -7,6 +7,9 @@ RUN apt-get update \
   && apt-get install -y --no-install-recommends \
     bash ca-certificates git ripgrep curl xz-utils make jq \
     golang-go \
+    libglib2.0-0 libnss3 libnspr4 libatk1.0-0 libatk-bridge2.0-0 \
+    libcups2 libdrm2 libxkbcommon0 libxcomposite1 libxdamage1 \
+    libxfixes3 libxrandr2 libgbm1 libpango-1.0-0 libcairo2 libasound2 \
   && rm -rf /var/lib/apt/lists/*
 
 RUN GOBIN=/usr/local/bin go install golang.org/x/tools/gopls@latest || true
@@ -17,6 +20,8 @@ RUN npm install -g --ignore-scripts @earendil-works/pi-coding-agent
 # scripts (husky etc.) crash headless installs. Route installs through
 # --ignore-scripts so ALL dotfiles packages (pi-subagents, todo tooling,
 # async agents, every extension) survive the bake.
+# MCP servers available to pi agents (matches the host setup).
+# cloakbrowser-mcp ships the browser automation MCP (bundled deps, no postinstall).
 COPY docker/npm-real /usr/local/bin/npm-real
 COPY docker/npm-shim /usr/local/bin/npm-ignore-scripts
 # rm first: /usr/local/bin/npm is a symlink into npm's lib dir, and COPY
@@ -39,6 +44,12 @@ COPY docker/bridge /bridge
 
 # Per-session pi sessions persist here (volume lvmh-sessions); package cache
 # shared across spawns via volume lvmh-pi-cache at /root/.pi/agent/cache.
+# MCP tooling: cloakbrowser-mcp global (bundled deps), npx for playwright,
+# and the standard MCP config the pi-mcp-adapter reads.
+RUN npm-real install -g --ignore-scripts cloakbrowser-mcp@1.4.0 \
+	&& mkdir -p /root/.config/mcp
+COPY docker/mcp.json /root/.config/mcp/mcp.json
+
 ENV PI_SESSION_DIR=/pi-sessions
 WORKDIR /workspace
 CMD ["node", "/bridge/index.mjs"]