MV3 Manifest Preflight - Chrome Web Store

Runs the same checker as our npm package on a Node.js runtime that pip installs for you (nodejs-wheel-binaries) - no system Node.js needed. Your files are checked locally.

25 rules over manifest.json: every line Manifest V3 or the Chrome Web Store upload refuses, with the fix beside it. The shipped MV2 fixture returns 19 findings, 16 of them errors that block the upload; the migrated file returns 0.

Install

mv3-manifest-preflight file

Node 18+. The same 25 rules as the VS Code extension, from a terminal or CI.

Free

• Open any manifest.json and see every Manifest V3 and Chrome Web Store upload blocker in it, all 25 rules, each with the exact replacement line - one file, finished, no key.
• --rules lists every rule

With a licence ($29 once)

• Scan every manifest.json in the workspace in one run and export the pre-submission report as a file you keep: Markdown for the reviewer, JSON for CI.

mv3-manifest-preflight --dir ./templates --report html --out report.html

A contract extension developer at $80/h costs more than the licence after 22 minutes of resubmission rework, and a rejected upload restarts the Chrome Web Store review queue.

Use from an AI agent (MCP)

Claude Code · Cursor · Windsurf · any MCP client - add to your MCP config:

{ "mcpServers": { "mv3-manifest-preflight": { "command": "mv3-manifest-preflight", "args": ["--mcp"] } } }

Tools: check_text and check_file (free) · check_dir (licence). The agent gets every finding with the line number.

Use in CI

- name: MV3 Manifest Preflight - Chrome Web Store
  run: pip install rulestamp-mv3-manifest-preflight && mv3-manifest-preflight --dir . --ci

The folder sweep, reports and CI mode need one licence — one payment, no subscription. Set READYSTACK_LICENSE=<key> or run --license <key> once.

Get a licence

Install (PyPI)

pip install rulestamp-mv3-manifest-preflight
mv3-manifest-preflight --help