# Reason

Connects your coding agent to Reason cloud workspaces over a remote HTTP MCP endpoint using OAuth.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 7
- Author: reason-machines
- License: MIT · policy=link-only · description only; the file stays with the author
- Source: https://github.com/reason-machines/reason-plugins
- Updated: 2026-10-16
- HTML: https://affpapa.org/en/nevibecode/mcp/reason

## What it does

This MCP server links your development environment to Reason at `https://mcp.reasonmachines.com/mcp`. It exposes v3 API operations directly to your agent, enabling background task execution, repo inspection, and pull request generation. The package brings no local binaries or hooks.

Authentication relies on browser OAuth rather than hardcoded credentials. New coding runs trigger asynchronously via `createSession`, returning a session link so you can monitor progress with `getSession`. File uploads through MCP tools cap at 1 MiB, while server responses stop at 2 MiB. If your task exceeds these sizes, you need the standard REST API.

The project previously ran under the name Ara, whose legacy endpoint now returns HTTP 410. Any old setup pointing to ara.so has broken and needs the new service address.

## Requirements
- Remote server: `https://mcp.reasonmachines.com/mcp`

## Install

### Claude Code (native platform)

**Platform CLI: remote server**
```bash
claude mcp add --transport http reason https://mcp.reasonmachines.com/mcp
```

### Codex

**Platform CLI: remote server**
```bash
codex mcp add reason --url https://mcp.reasonmachines.com/mcp
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "reason": {
            "url": "https://mcp.reasonmachines.com/mcp"
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "reason": {
            "type": "http",
            "url": "https://mcp.reasonmachines.com/mcp"
        }
    }
}
```

### Gemini CLI

**Platform CLI: remote server**
```bash
gemini mcp add -t http reason https://mcp.reasonmachines.com/mcp
```

## When to use it
- Trigger an asynchronous Reason coding session on a repository
- Fix broken CI runs on a pull request without skipping test suites
- Review existing pull requests directly from the client
- Inspect progress and recent outcomes of active Reason sessions

## Example prompts
- /reason-review https://github.com/acme/web/pull/42
- /reason-status

## Similar
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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md