AI coding plugin
Keep coding with AI. Hand the heavy work to XCR.
A free plugin for Codex, Claude Code and Cursor. Tasks are billed by usage.
Codex, Claude Code, Grok Build and Cursor on macOS and Linux (Windows through WSL). Product names are used only to describe compatibility.
A copy, not your files
Only what's needed is sent
Requirements and results come back
Set up in about a minute, no terminal needed
- 01
Create a XCR account
Sign in with Google or your email. No card needed to start.
- 02
Copy one instruction and paste it into your AI coding tool
On the Install on a computer page of your console, pick Codex, Claude Code, Grok Build or Cursor and click Copy. Paste it into your AI coding tool and allow it to run the command. Cursor users can click Add to Cursor instead. The page lists exactly what will change on your computer.
- 03
Restart your AI coding tool and work as usual
Ask for what you want. Big jobs are handed to XCR; small edits and questions stay with your AI coding tool.
Requirements+
Requires Node.js 20 or later; if it's missing, your AI coding tool installs it first (and asks you before it does). Works in git projects and in plain folders. Checks run offline in a sandbox (macOS built in; on Linux install bubblewrap). Prefer the terminal? The Install on a computer page also gives you the command.
Published comparison · 13 Oct 2026
22 tasks: XCR and Astra each completed 19. Estimated XCR cost was 41.8% lower.
See the data and notes+
| Plan | Completed | Estimated sample cost |
|---|---|---|
| Astra API workflow | 19/22 | $3.0708–$3.4858 |
| XCR evaluation workflow | 19/22 | $1.6396–$1.7870 |
XCR self-test, 13 Oct 2026: 12 small tasks and 10 public historical tasks from two utility libraries. XCR cost includes 20% markup; Astra is API cost. Uses XCR’s upper estimate and Astra’s lower estimate, including failed tasks. Not a production-version, subscription-quota or overall-capability guarantee. The 100× figures are arithmetic only. The report uses its original cost-plus-20% calculation and excludes the current $0.02 fixed task fee.
Report text is in Chinese. Full data covers both rounds; individual baseline results are kept separate.
What happens when your AI coding tool hands over a task+
01 · A copy, not your files
XCR copies your project as it is right now, including uncommitted work, and works on the copy.
02 · Only what's needed is sent
XCR picks the relevant files, removes secret values, and never reads files like .env or private keys.
03 · Coding implementation
Larger jobs may be divided into parts. XCR returns changes, checks and requirement status within a task budget.
04 · Your checks decide
Failed checks guide repairs within the task budget. Review the final changes and any unresolved requirements.
05 · Requirements and results come back
The report lists done, not done and needs-you requirements, files and checks. Incomplete or unverified requirements keep the result aside for review. Passing checks alone do not prove the result is correct.
06 · Your AI coding tool finishes
It reviews the change and handles anything that needs the internet: installing new packages, running tests that call live services.
What your AI coding tool gets back
A short, exact report your AI coding tool can act on:
XCR task 7f3a…: PARTIAL · kept aside · [charge] Requirements: - [done] CSV export with date and status filters - [needs you] Install the declared package; rerun checks Files (4): export.ts, service.ts, orders.ts, export.test.ts Checks: typecheck passed, tests need install (offline) Review, then apply: mc2_code_apply (task_id "7f3a…").
What to hand to XCR
- A feature that touches several files
- Writing the tests a module is missing
- Fixing a bug until the test suite is green
- Refactors and API migrations
- Database or config migrations with tests
Keep these with your AI coding tool
- One-line edits and quick questions
- Design decisions and code review
- Anything needing the internet, accounts or secrets
- Code that must not be sent to third parties
Install, privacy and cost details+
Exactly what setup changes
Codex: adds an [mcp_servers.mc2] section to ~/.codex/config.toml and a short rule to ~/.codex/AGENTS.md. Claude Code: registers the mc2 server for your user (claude mcp add) and adds a short rule to ~/.claude/CLAUDE.md. Grok Build: adds an [mcp_servers.mc2] section to ~/.grok/config.toml. Cursor: adds mc2 to ~/.cursor/mcp.json. The install page lists every change before you copy the instruction; original files are backed up, and uninstalling restores them exactly.
Your code and your secrets
The parts of the project a task needs are sent to XCR and to the AI providers doing the work, then discarded: XCR does not store your code. Secret values are removed before anything is sent, and . env files, private keys and similar files are never read. No providers headquartered in mainland China are used.
Offline by design
XCR runs your checks without internet access and only lets them write inside the working copy, so code under test cannot send anything out. It never installs packages. Steps that need the internet are listed for your own AI coding tool, which runs them on your computer with your permissions.
What it costs
Actual model usage plus 20%, and one $0.02 fixed fee per task with successful model work. Model retries within the same task do not add more fixed fees. The task cap includes both. Incomplete work can still be charged; tasks without successful model work are not charged.
Pausing and removing
Your console has the switches: pause everything on Overview, or one computer or project under Computers & projects. To remove XCR from a computer, tell your AI coding tool "uninstall XCR", run `npx -y https://xcr.ai/downloads/mc2-plugin-0.1.3.tgz uninstall`, or click "Remove from this computer" under Computers & projects.
Why it adds a rule
The installed rule tells your AI coding tool when to delegate and how to review changes. You can inspect the rule and disable delegation with mc2 off.
AI providers · Privacy · Pricing
Codex is a trademark of OpenAI; Claude Code of Anthropic; Grok Build of xAI; Cursor of Anysphere. XCR is not affiliated with or endorsed by them.