Build & Runtime

NanoClaw runs a split stack: the host is Node + pnpm, the agent container is Bun. They communicate exclusively through two SQLite files per session — there are no shared modules between them, which is what lets them use different runtimes cleanly.

Why the split

• Host stays on Node because Baileys (WhatsApp) depends on libsignal-node native bindings and a long-tested WebSocket/HTTP stack. Bun's Node-API compat has improved, but this isn't where we want risk.
• Container runs Bun because bun:sqlite is built-in (no native compile of better-sqlite3 per image rebuild), source runs directly (no tsc build step at image build or session wake), and bun install is ~5-10× faster than npm install.

Host and container each have their own package tree:

/                             pnpm + Node 22
  pnpm-lock.yaml              host deps (channels, Chat SDK, Baileys, better-sqlite3, etc.)
  pnpm-workspace.yaml         minimumReleaseAge + onlyBuiltDependencies policy

/container/agent-runner/      Bun 1.3+
  bun.lock                    agent-runner runtime deps (Claude Agent SDK, MCP SDK, zod, etc.)
  package.json                @types/bun, typescript devDeps for type-checking

The container image also has pnpm + Node inside for global CLIs (@anthropic-ai/claude-code, agent-browser, vercel). Those are Node binaries the agent invokes at runtime, not library deps. Keeping them on pnpm preserves the supply-chain policy for CLI versions.

Lockfiles

Both are committed. CI and the Dockerfile run --frozen-lockfile variants — any drift between package.json and lockfile fails the build.

Supply chain

• Host + global CLIs (pnpm): minimumReleaseAge: 4320 (3-day hold on new versions), onlyBuiltDependencies allowlist for postinstall scripts. See pnpm-workspace.yaml and docs/SECURITY.md.
• Agent-runner (Bun): no release-age policy — Bun doesn't have an equivalent today. The defenses are bun.lock pinning plus version-pinned CLIs/Bun itself via Dockerfile ARGs. When bumping @anthropic-ai/claude-agent-sdk or any runtime dep, review the release date on npm and bump deliberately, not via bun update.

Image build surface

container/Dockerfile is a single-stage build on node:22-slim:

• Pinned ARGs — BUN_VERSION, CLAUDE_CODE_VERSION, AGENT_BROWSER_VERSION, VERCEL_VERSION. Bump deliberately in PRs.
• CJK fonts — ARG INSTALL_CJK_FONTS=false. container/build.sh reads INSTALL_CJK_FONTS from .env and passes it through. Default build saves ~200MB; opt in when the user works with Chinese/Japanese/Korean content.
• BuildKit cache mounts — /var/cache/apt, /var/lib/apt, /root/.bun/install/cache, /root/.cache/pnpm. Rebuilds where package.json/bun.lock haven't changed are fast. Requires BuildKit (default on Docker 23+, Apple Container-compat).
• tini as init — reaps Chromium zombies, forwards signals so in-flight outbound.db writes finalize on SIGTERM.
• entrypoint.sh (extracted) — exec bun run /app/src/index.ts under tini. Readable and diffable.
• No compiled /app/dist — Bun runs TS directly. The host also mounts fresh source over /app/src at session start, so host edits take effect without rebuilding the image.

Session wake (two paths)

1. Base image ENTRYPOINT — used for stdin-piped test invocations like the sample in container/build.sh: tini --> entrypoint.sh captures stdin to /tmp/input.json, then exec bun run src/index.ts.
2. Host-spawned session — src/container-runner.ts at line ~301 uses --entrypoint bash with -c 'exec bun run /app/src/index.ts'. Bypasses tini (Docker's default PID 1 handling applies). Stdin is unused; all IO flows through the mounted session DBs.

Both paths end with Bun running the same source file from /app/src/index.ts.

CI shape

.github/workflows/ci.yml installs both Node (with pnpm cache) and Bun, then runs in order:

1. pnpm install --frozen-lockfile (host)
2. bun install --frozen-lockfile in container/agent-runner/ (container)
3. pnpm run format:check
4. pnpm exec tsc --noEmit (host typecheck)
5. pnpm exec tsc -p container/agent-runner/tsconfig.json --noEmit (container typecheck)
6. pnpm exec vitest run (host tests)
7. bun test in container/agent-runner/ (container tests)

Any failure fails the PR.

Key invariants

• Session DBs must use journal_mode=DELETE. WAL's -shm memory-map doesn't cross VirtioFS between host and guest. See the doc comment at the top of container/agent-runner/src/db/connection.ts and src/session-manager.ts.
• Named SQL parameters in the container require the prefix in JS object keys. bun:sqlite does not auto-strip @/$/: the way better-sqlite3 does on the host. Use $name in both SQL and keys: .run({ $id: msg.id }). Positional ? params work normally.
• Agent-runner tests run under bun:test, not vitest. vitest.config.ts excludes the container/agent-runner/ tree because vitest runs on Node and can't load bun:sqlite.
• No tsc build step in the container image. Re-adding one would reintroduce the ~200-500ms per-session-wake cost we removed.
• Global container CLIs stay on pnpm, not Bun. agent-browser, @anthropic-ai/claude-code, vercel and any future Node CLIs the agent invokes should be pinned versions under the Dockerfile's pnpm global-install block. bun install -g would bypass the pnpm supply-chain policy.

Migration history

This structure replaced a uniform npm-on-Node stack across both host and container. The pnpm migration landed first (PR #1771) to bring the host under supply-chain policy, then the container moved to Bun to eliminate native-module compilation and the per-wake tsc step. The split was chosen over going full-Bun because Baileys' native deps are the main risk surface on the host — the container has no such deps, so it benefits from Bun without taking the risk.