node.run

The JavaScript counterpart to python.run. Runs JS code (node -e) or an argv-shape command inside a Node-equipped sidecar. Node 20 LTS + npm + pnpm + yarn + tsc (TypeScript compiler) preinstalled.

⚙️ Setup note: same as python.run — needs make sidecars to build the image, plus HELMDECK_SIDECAR_NODE=helmdeck-sidecar-node:dev in .env.local, plus a control-plane recreate.

Inputs

Field	Type	Required	Default	Notes
code	string	one of	—	JS code to run via node -e.
command	array	one of	—	argv-style command (e.g. ["npx", "tsc", "--noEmit"]).
cwd	string	no	—	Working directory.
stdin	string	no	—	Bytes piped to stdin.

Outputs

Field	Type	Notes
stdout	string
stderr	string
exit_code	number
runtime	string	Always node.

Vault credentials needed

None directly. Same env-var-based vault pattern available as python.run if needed.

Use it from your agent (OpenClaw chat-UI worked example)

Prompt (sent in OpenClaw chat UI / openclaw-cli agent):

Use the helmdeck__node-run tool to execute this JavaScript: const v = process.version; const r = require("crypto").createHash("sha256").update("helmdeck").digest("hex"); console.log(v, r). Report the Node version and the sha256 hex digest.

Tool call (1 call, no failures):

{
  "name": "helmdeck__node-run",
  "arguments": {
    "code": "const v = process.version; const r = require(\"crypto\").createHash(\"sha256\").update(\"helmdeck\").digest(\"hex\"); console.log(v, r);"
  }
}

Pack response (truncated):

{"pack":"node.run","version":"v1","output":{"exit_code":0,"runtime":"node","stderr":"","stdout":"v20.20.2 ab8f104b28f3f2ca9f9f41099400b31114ed7d7599487666f1e6e998616fb8b4\n"},"duration_ms":2284290299,"session_id":"4ab3278a-2601-4897-a475-8fce0886d3f2"}

Agent's final reply:

Node version: v20.20.2
SHA‑256 hex digest of “helmdeck”: ab8f104b28f3f2ca9f9f41099400b31114ed7d7599487666f1e6e998616fb8b4

Verified via OpenClaw 2026.5.6 + helmdeck v0.9.0-dev + openrouter/openai/gpt-oss-120b on 2026-05-07 (cost: $0.1351).

Developer reference (curl)

curl -fsS -X POST http://localhost:3000/api/v1/packs/node.run \
  -H "Authorization: Bearer $JWT" -H 'Content-Type: application/json' \
  -d '{"code":"console.log(\"Node\", process.version); console.log(2+2);"}'

Captured response:

{
  "pack": "node.run",
  "version": "v1",
  "output": {
    "exit_code": 0,
    "runtime": "node",
    "stderr": "",
    "stdout": "Node v20.20.2\n4\n"
  },
  "session_id": "3a78ae97-9cb7-4648-8393-de5aeb683508"
}

Error codes

Same closed set as python.run:

Code	Triggers
invalid_input	both / neither of code/command set
session_unavailable	Node sidecar image missing
handler_failed	container exec fails

Non-zero exits are not errors — they're surfaced as exit_code with the corresponding stderr.

Session chaining

Same pattern as python.run — own sidecar, can be chained off a repo.fetch by passing the clone_path as cwd.

Async behavior

Synchronous. ~1–2 second cold start, fast on warm sessions.

See also

• python.run — Python sibling.
• cmd.run — for ad-hoc shell work in the browser sidecar.
• Source: internal/packs/builtin/node_run.go.
• ADR 001 — sidecar pattern.
• SIDECAR-LANGUAGES.md — adding new language sidecars.