turnpack

Try the demo · See an example · Set it up · The three tools · What it saves · Safety · FAQ

AI coding agents work in round trips: the model asks for something, waits, reads the result, and asks again. Each trip is a full model turn, a wait for the first token and then the tokens themselves. Today's apps already run independent reads side by side, so the trips that are left are the ones that depend on each other. A search has to come back before the agent knows which files to open. An edit has to land before the tests can run. And when the tests fail at the end, your repo is left half-edited while the agent spends more turns backing out.

Turnpack is a small local MCP server that gives the agent three tools to fold those trips together:

It runs entirely on your machine: no API keys, no account, no telemetry, no network calls, and zero runtime dependencies. It works with Claude Code and Claude Desktop, Codex CLI and the ChatGPT desktop app, OMP, Grok Build, Cursor, Gemini CLI, OpenCode and anything else that speaks MCP over stdio.

Try it in 10 seconds

npx turnpack demo

This builds a throwaway repo in your temp folder, runs all three tools against it, and deletes it. Nothing in your own projects or AI app config is touched.

The recording is generated from the real output of those two commands (scripts/render-assets.py), so it cannot drift from what the tool does. doctor is run on a temporary home directory in which init has just set up five apps, which is why it lists them.

Want to run it straight from this repository instead of npm? npx github:OnlyTerp/turnpack demo

What it looks like

A rename that misses a call site is the classic way an agent breaks a build. Here is that mistake going through ship. The agent renames a function but forgets the file that imports it:

{
  "edits": [
    {
      "path": "src/tax.js",
      "search": "export function calculateTax(amount)",
      "replace": "export function computeTax(amount)"
    }
  ],
  "verify": "npm test"
}

FAILED_AND_ROLLED_BACK: verify "npm test" failed (exit code 1).

Restored 1 file(s) to byte-exact pre-edit snapshots. The workspace is unchanged; fix the edit and ship again.

Changed by this call and tested together: src/tax.js (line 3).

The failing output does not mention any file this call changed. It names src/invoice.js:1, a file this call did not change: often a caller or a test the change has not reached yet.

$ npm test
> test
> node test/invoice.test.js

file:///home/you/shop/src/invoice.js:1
import { calculateTax } from "./tax.js";
         ^^^^^^^^^^^^
SyntaxError: The requested module './tax.js' does not provide an export named 'calculateTax'

The repo is exactly as it was, and the reply names the file the edit missed. It ships again with both files:

{
  "edits": [
    {
      "path": "src/tax.js",
      "search": "export function calculateTax(amount)",
      "replace": "export function computeTax(amount)"
    },
    {
      "path": "src/invoice.js",
      "search": "calculateTax",
      "replace": "computeTax",
      "replace_all": true
    }
  ],
  "verify": "npm test"
}

SHIPPED_AND_VERIFIED in 283ms: 2 file(s) changed: src/tax.js (line 3), src/invoice.js (lines 1, 4).

$ npm test  (passed)
> test
> node test/invoice.test.js

ok - invoice total includes tax

Two turns, and at no point was the working tree broken. Both replies are real output, with Node's internal stack frames cut from the first and the project path shortened.

{
  "query": "calculateTax",
  "files": ["src/tax.js", { "path": "src/invoice.js", "symbol": "invoiceTotal" }, ".env"],
  "git_status": true
}

## GIT STATUS
## master

## SEARCH "calculateTax" (3 hits, engine=rg)
src/invoice.js:1: import { calculateTax } from "./tax.js";
src/invoice.js:4:   return Number((subtotal + calculateTax(subtotal)).toFixed(2));
src/tax.js:3: export function calculateTax(amount) {

## FILES (3)
### FILE: src/tax.js (L1-6/6)
1 | export const TAX_RATE = 0.08;
2 |
3 | export function calculateTax(amount) {
4 |   return Number((amount * TAX_RATE).toFixed(2));
5 | }
6 |

### SYMBOL: src/invoice.js :: function invoiceTotal (L3-5/6)
3 | export function invoiceTotal(subtotal) {
4 |   return Number((subtotal + calculateTax(subtotal)).toFixed(2));
5 | }

### FILE: .env
[REDACTED SECRET FILE: .env — pass allow_secrets: true if intentional]

Set it up

You need Node.js 22 or newer. Then:

npx turnpack init

npx turnpack doctor

init finds the AI apps you have installed, shows you exactly what it would change, and asks before writing. By default that is Claude Code, Claude Desktop, Codex (the CLI and the ChatGPT desktop app share one config), OMP and Grok Build.

• The entry it writes starts a file on your machine, with an absolute path to Node. That starts in tens of milliseconds, works offline, cannot change version without you, and does not depend on the PATH a desktop app happens to be given. If you ran init through npx, the server's files are first copied to ~/.turnpack/versions/<version>, because the npx cache gets cleaned. Prefer a portable entry? init --npx writes npx -y turnpack@<version> serve instead, pinned to the version.
• It then starts the server with that exact command and tells you whether it answered. An entry in a config file and an entry that works are different things.
• **It