devin-plugin-cc

Devin Plugin for Claude Code and Codex

Devin Plugin for Claude Code and Codex brings Devin into a terminal coding workflow for AI code review, delegated coding tasks, cloud handoffs, and Fusion sidekick sessions. Claude Code uses slash commands such as /devin:review and /devin:fusion; Codex and other agents use the portable skills and the shared Devin CLI runtime.

The project is an open-source Claude Code plugin and cross-agent integration for Devin AI. It uses the local Devin CLI for one-shot work and the Devin API for cloud handoffs.

What it does

Capability	Description
AI code review	Review a working tree or branch diff with read-only Devin analysis.
Adversarial review	Examine implementation choices, assumptions, tradeoffs, and failure modes.
Task delegation	Send a bounded coding task to Devin with workspace-aware state and resumable sessions.
Fusion workflow	Keep Claude Opus 5.5 or GPT 6 Astra as the lead while Devin handles bounded mechanical or test-heavy work.
Cloud handoff	Open a Devin session with repository, branch, context, and uncommitted diff.
Agent skills	Use the same runtime from Codex, OpenCode, Cursor, Gemini CLI, Amp, Jules, Aider, and other agents.
Review gate	Optionally review the previous Claude turn before the session ends.

Modeled after openai/codex-plugin-cc, adapted to Devin's interfaces:

• Local runs use devin -p (one-shot, non-interactive) instead of Codex's app-server/broker — no daemon required.
• Session continuation uses devin -c (latest) and devin -r <session-id> (explicit).
• Reviews return Markdown findings rather than a JSON schema.
• Cloud handoffs create sessions at app.devin.ai via the Devin API.

Requirements

• Devin CLI installed and authenticated (devin auth status), or DEVIN_API_KEY set for cloud handoffs.
• Node.js >= 18.18 (for the companion runtime).
• Git (review commands run inside a repository).

Install

Clone and validate the repository first:

git clone https://github.com/TheOnlyFusionCube/devin-plugin-cc
cd devin-plugin-cc
npm install
npm run doctor

Inside Claude Code, add the local marketplace and install the plugin:

/plugin marketplace add .
/plugin install devin@devin-plugin-cc

The equivalent shell commands use the GitHub marketplace directly:

claude plugin marketplace add TheOnlyFusionCube/devin-plugin-cc
claude plugin install devin@devin-plugin-cc

Or point Claude Code at this repo with --plugin-dir.

Then run:

/devin:setup

to verify the Devin binary, auth, and cloud credentials.

Codex, OpenCode, Cursor, Gemini CLI, and other agents

The runtime is a plain Node CLI — every agent can drive it; only the command wrappers are Claude-specific. Three standard entry points ship in this repo:

• AGENTS.md — read natively by Codex CLI, OpenCode, Cursor, Gemini CLI, Amp, Jules, and Aider. It documents the full devin-companion.mjs command surface.
• skills/devin/ and skills/fusion/ — portable agent skills. Copy both to ~/.codex/skills/, .agents/skills/ in your project, or your tool's skills dir.
• llms.txt — a compact machine-readable summary and doc map at the repo root for agents and AI search tools.

Codex has a native plugin install that uses the same marketplace manifest:

codex plugin marketplace add TheOnlyFusionCube/devin-plugin-cc
codex plugin add devin@devin-plugin-cc          # main plugin
codex plugin add fusion@devin-plugin-cc        # Fusion skill ($fusion)
codex plugin add devin-skills@devin-plugin-cc  # portable runtime skill

To install only the two portable skills instead of the whole plugin:

npx skills add TheOnlyFusionCube/devin-plugin-cc -a codex -g -s devin -s fusion -y

Omit -g for project scope. Then invoke Fusion with $fusion <task> (or pick it in /skills) and use the Devin skill commands.

The Devin CLI reads the same marketplace manifest — this installs the plugin for Devin's own sessions:

devin plugins install TheOnlyFusionCube/devin-plugin-cc#plugins/devin

Commands

Command	What it does
/devin:setup	Check devin binary, auth status, and DEVIN_API_KEY. Enable/disable the stop review gate (--enable-review-gate / --disable-review-gate).
/devin:review [focus]	Read-only review of the working tree, or --base <ref> for a branch diff. --background runs async, --wait polls to completion.
/devin:adversarial-review [focus]	Read-only review focused on implementation choices, tradeoffs, assumptions, and failure modes. Same flags as review.
/devin:rescue <task>	Delegate diagnosis/implementation to Devin via the devin-rescue subagent. Write-capable by default; --read-only/--background/--resume supported.
/devin:fusion <task>	Run a frontier-lead workflow with Claude Opus 5.5 as lead and Devin as the sidekick for bounded mechanical work.
/devin:handoff <task>	Create a cloud Devin session carrying repo, branch, context, and a bounded uncommitted diff. --wait polls until terminal.
/devin:status [job-id]	List local jobs and cloud handoffs, with live phase/elapsed info.
/devin:result [job-id]	Show the complete stored output of a finished job.
/devin:cancel <job-id>	Kill a running local job's process tree; for cloud handoffs also asks the session to stop.

Review commands are strictly read-only: they never apply fixes. Arguments are parsed POSIX-style — flags first, then free text passed through verbatim.

The default model is pinned to swe-2-max (SWE-2 Max); pass --model <id> to any review/task command to override — devin models list shows what your account can use.

Fusion

Fusion keeps the frontier model responsible for intent, planning, ambiguity, and final review while Devin handles bounded mechanical or test-heavy work in its own context. Cognition describes this sidekick pattern as two parallel agents with dynamic handoffs as the task evolves. See Devin Fusion. This repo reimplements that pattern as prompts — the lead is your Claude or Codex session, not a separate Devin Fusion harness.

In Claude Code, run /devin:fusion <task>. The installed plugin command is namespace-scoped, so Claude exposes it as /devin:fusion; Claude Opus 5.5 is the lead model named by the command. Devin remains the sidekick and uses the existing swe-2-max default unless you override it.

In Codex, install the fusion skill (via codex plugin add fusion@devin-plugin-cc or the npx skills command above) and invoke $fusion <task> — Codex skills use $, not /. GPT 6 Astra is the lead model named by that skill, with Devin as the sidekick.

Hooks

• SessionStart — exports session metadata for job attribution.
• SessionEnd — kills local jobs still running from this session. Detached cloud handoffs are left alone and reconciled on the next status/result call.
• Stop (opt-in) — when enabled via /devin:setup --enable-review-gate, reviews the previous turn's diff and blocks session stop only on a BLOCK: verdict. Infrastructure failures fail open with a warning.

State

Per-workspace state lives outside the repo under the OS temp dir (<tmp>/devin-companion/<slug>/): state.json plus per-job .json/.log/.prompt.md files. Redirect with CLAUDE_PLUGIN_DATA. State writes are atomic; job files are garbage-collected when the 50-job history cap prunes them.

Layout

AGENTS.md                         # cross-agent instructions (Codex, OpenCode, Cursor, …)
llms.txt                          # agent-readable summary + doc map
skills/devin/SKILL.md             # portable Devin runtime skill
skills/fusion/SKILL.md            # portable Fusion lead/sidekick skill
.claude-plugin/marketplace.json   # marketplace manifest (Claude Code and Codex)
.github/workflows/ci.yml          # CI: install check, tests, doctor
scripts/install.mjs               # npm prepare hook — required-file sanity check
plugins/devin/
  .claude-plugin/plugin.json      # plugin manifest
  commands/*.md                   # /devin:* slash commands
  agents/devin-rescue.md          # thin forwarding subagent
  hooks/hooks.json                # lifecycle + stop-gate wiring
  prompts/*.md                    # review / adversarial / gate templates
  scripts/devin-companion.mjs     # CLI dispatcher — the universal entry point
  scripts/lib/*.mjs               # args, state, jobs, git, devin, cloud, render
  skills/*/SKILL.md               # runtime, result-handling, prompting docs
tests/                            # node:test suite + fake devin fixture

Frequently asked questions

What is devin-plugin-cc?

devin-plugin-cc is a Claude Code plugin and portable agent integration that adds Devin AI code review, task delegation, cloud handoffs, and Fusion workflows to a repository-based coding workflow.

Does it work with Claude Code and Codex?

Yes. Claude Code installs the devin marketplace plugin and exposes commands such as /devin:review, /devin:rescue, and /devin:fusion. Codex loads skills/devin/ and skills/fusion/, then calls the same devin-companion.mjs runtime.

What is Fusion mode?

Fusion keeps a frontier model as the lead for intent, planning, ambiguity, architecture, and final review. Devin acts as a sidekick for bounded mechanical, repetitive, or test-heavy work with its own task context.

Does local use require a Devin API key?

No. Local review and task commands use an installed and authenticated Devin CLI. Only cloud handoffs require DEVIN_API_KEY.

Development

npm test          # node --test — incl. a fake devin binary fixture
node --check <file>   # syntax-check any module

DEVIN_COMPANION_DEVIN_BINARY overrides the devin binary path (used by tests; handy for smoke tests against a stub).

Credits

Derived from openai/codex-plugin-cc by OpenAI — original concept, architecture, and much of the companion runtime are theirs, adapted for the Devin CLI and Devin API. See NOTICE.

Disclaimer

devin-plugin-cc is an independent community project. It is not affiliated with, endorsed by, or sponsored by Cognition AI (the company behind Devin and Devin Desktop), Anthropic, or OpenAI. "Devin", "Devin Desktop", "Claude", "Claude Code", and "Codex" are trademarks of their respective owners; references here are descriptive only.

License

Apache-2.0 — see LICENSE and NOTICE.