Claude Code Plugin for Any Agent

Use an already-installed and authenticated Claude Code CLI from Codex or any other MCP-compatible harness.

This is an MCP server, not a host-specific plugin: it communicates over standard input/output and starts the local claude executable. That makes its tool interface portable across MCP clients while preserving your existing CLI authentication and default model configuration.

What it provides

Every task and review accepts optional model and effort fields. If model is omitted, the server does not send --model, so the local CLI uses its normally configured default. effort maps directly to Claude Code's --effort option (low, medium, high, xhigh, or max).

Related MCP server: claude-code-mcp

Prerequisites

• Node.js 18 or newer

• Claude Code already installed and authenticated

• Codex CLI, if you are using the Codex installation path below

Check the local prerequisites:

node --version
claude --version
codex --version

Install in Codex

Clone the repository, or use your existing clone:

git clone https://github.com/sarthchawla/claude-code-as-plugin.git
cd claude-code-as-plugin

Register the server. Run this from the cloned repository. The command records absolute paths for both Node and the local CLI, so it also works when Codex is launched from a desktop app with a minimal PATH:

MCP_SERVER_PATH="$(pwd)/bin/claude-code-mcp.mjs"
MCP_NODE_BIN="$(command -v node)"
MCP_CLAUDE_BIN="$(dirname "$(command -v claude)")"
MCP_PATH="$MCP_CLAUDE_BIN:$(dirname "$MCP_NODE_BIN"):$PATH"

codex mcp add claude-code \
  --env CLAUDE_CODE_MCP_REVIEW_AFTER_RUN=false \
  --env "PATH=$MCP_PATH" \
  -- "$MCP_NODE_BIN" "$MCP_SERVER_PATH"

Verify registration:

codex mcp list

Fully restart Codex. The five tools listed above should then be available.

Enable the post-task review hook

The hook is disabled by default. To enable it, replace the registration:

codex mcp remove claude-code

MCP_SERVER_PATH="$(pwd)/bin/claude-code-mcp.mjs"
MCP_NODE_BIN="$(command -v node)"
MCP_CLAUDE_BIN="$(dirname "$(command -v claude)")"
MCP_PATH="$MCP_CLAUDE_BIN:$(dirname "$MCP_NODE_BIN"):$PATH"

codex mcp add claude-code \
  --env CLAUDE_CODE_MCP_REVIEW_AFTER_RUN=true \
  --env "PATH=$MCP_PATH" \
  -- "$MCP_NODE_BIN" "$MCP_SERVER_PATH"

The hook runs only after a successful claude_run. It uses a restricted, read-only tool set and returns its findings under review in the same tool response. It adds latency and usage, and does not attempt automatic fixes or feedback loops.

For a customized hook, add either optional environment variable during codex mcp add:

--env 'CLAUDE_CODE_MCP_REVIEW_MODEL=sonnet'
--env 'CLAUDE_CODE_MCP_REVIEW_PROMPT=Review for correctness, security, and missing tests. Do not modify files.'

Use from Codex

Ask Codex to use a tool directly. Typical calls look like these:

{
  "prompt": "Investigate the failing tests and make the smallest safe fix.",
  "cwd": "/absolute/path/to/project",
  "model": "sonnet",
  "effort": "high"
}

Omit model to use the local CLI default:

{
  "prompt": "Review the current changes for regressions.",
  "cwd": "/absolute/path/to/project"
}

The default permission mode is manual. claude_run also supports permission_mode, allowed_tools, max_budget_usd, timeout_ms, and review_after_run for a single-call hook override. Use claude_review with model: "opus" and an effort value when you want a higher-effort read-only review.

Background jobs

Set background to true to receive a jobId immediately:

{
  "prompt": "Investigate the CI regression and prepare a minimal fix.",
  "cwd": "/absolute/path/to/project",
  "background": true
}

Then use:

1. claude_status with job_id while the task runs.

2. claude_result with job_id after status is completed.

3. claude_cancel with job_id to stop it.

Cancellation sends SIGTERM to the subprocess group, followed by SIGKILL after five seconds if needed. Job state and output are stored only in memory; restarting the MCP server loses prior job history.

Configure another MCP harness

Use the standard mcpServers entry in examples/mcp-server.json, replacing the placeholder path with the absolute location of bin/claude-code-mcp.mjs:

{
  "mcpServers": {
    "claude-code": {
      "command": "/absolute/path/to/node",
      "args": ["/absolute/path/to/claude-code-as-plugin/bin/claude-code-mcp.mjs"],
      "env": {
        "CLAUDE_CODE_MCP_REVIEW_AFTER_RUN": "false",
        "PATH": "/directory-containing-claude:/directory-containing-node:/usr/local/bin:/usr/bin:/bin"
      }
    }
  }
}

Troubleshooting

• The tools do not appear: fully quit and reopen Codex after registration. Existing tasks do not always reload MCP configuration.

• The server is unavailable: rerun the registration commands above. They pass absolute Node and CLI paths to Codex, avoiding desktop-app PATH differences.

• The model is not what you expected: omit model to use the CLI default, or supply the desired model alias/value only for that invocation.

• A background job disappeared: jobs are process-local. Re-run the task after restarting Codex or the MCP server.

• Update or remove the server: use codex mcp remove claude-code, then run the registration command again (or leave it removed).

Security

Any MCP client that can call this server can ask the local CLI to operate in its supplied cwd. Register it only with trusted harnesses and repositories. Keep the default manual permission mode unless the calling environment provides a suitable sandbox.

Development

npm test