# Fable Mode MCP server

> Enforces mechanical write gates, evidence requirements, and adversarial red-teaming for AI coding agents to prevent premature workspace writes.

- Repository: https://github.com/REX-codebase/fable-mode
- Page: https://hostedmcp.org/servers/rex-codebase/fable-mode
- Transport: stdio
- Stars: 26
- License: MIT
- Latest version: 1.3.5

## Install

### Claude Code

```sh
claude mcp add fable-mode -- uvx fable-engine
```

### Cursor (`~/.cursor/mcp.json`)

```json
{
  "mcpServers": {
    "fable-mode": {
      "command": "uvx",
      "args": [
        "fable-engine"
      ]
    }
  }
}
```

### VS Code (`.vscode/mcp.json`)

```json
{
  "servers": {
    "fable-mode": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "fable-engine"
      ]
    }
  }
}
```

### Claude Desktop (`claude_desktop_config.json`)

```json
{
  "mcpServers": {
    "fable-mode": {
      "command": "uvx",
      "args": [
        "fable-engine"
      ]
    }
  }
}
```

### Codex (`~/.codex/config.toml`)

```toml
[mcp_servers.fable-mode]
command = "uvx"
args = ["fable-engine"]
```

### Gemini CLI (`~/.gemini/settings.json`)

```json
{
  "mcpServers": {
    "fable-mode": {
      "command": "uvx",
      "args": [
        "fable-engine"
      ]
    }
  }
}
```

## FAQ

### How does Fable Mode prevent agents from writing too early?

It uses mechanical gates rather than prompt advice, including time-locked deliberation and proof prerequisites that must be met before the workspace is unlocked.

### Does Fable Mode require extra RAM or local models for evidence auditing?

No, the optional AI evidence adjudicator uses a single bounded HTTPS call to an external reviewer model and requires no extra local RAM.

### Is Fable Mode a guarantee of flawless code?

No, it is a checkable workflow designed to make agents more deliberate, but it does not claim to produce perfect code.

### Can I use Fable Mode with my existing agent?

Yes, it is not a framework lock-in and works alongside your current agent via the Model Context Protocol.