ClaudeSmalltalk

Connect Claude Desktop to a live Smalltalk programming environment. Browse classes, evaluate expressions, define methods, and run autonomous code review — all against a running Squeak or Cuis image.

Developed by John M McIntosh, Corporate Smalltalk Consulting Ltd. 2026

What It Does

The Squeak VM provides 14 MCP tools — evaluate code, browse classes, read/write methods, navigate hierarchies, and save the image. Claude Desktop accesses them via smalltalk_task, which delegates all Smalltalk interaction to a locally-configured LLM (Ollama for free/local, or Anthropic/OpenAI/xAI) — no source code leaves your machine.

You → Claude Desktop → smalltalk_task → Your LLM → Live Smalltalk Image (TCP)
                        (MCP server)     (Ollama)    (Squeak or Cuis)

The agent isolates Smalltalk reasoning from your chat model. Claude Desktop triggers the work, but a separate model (which can be local and free) does the actual Smalltalk coding.

Quick Start

1. Get a Smalltalk VM and Image

Squeak (recommended):

• Download Squeak 6.0 — the All-in-One package includes VM and image
• Follow SQUEAK-SETUP.md to install the MCP server into the image

Cuis Smalltalk:

• Clone Cuis-Smalltalk-Dev
• Follow CUIS-SETUP.md to build a ClaudeCuis image

macOS note: Place the VM and image files in /Applications/ or your home directory. Files in ~/Documents/ or ~/Desktop/ may be blocked by macOS privacy restrictions (TCC). See macOS Permissions below.

2. Create a Configuration File and Install

Follow CLAUDE-README-MCPB.md — it covers creating your smalltalk-mcp.json config and installing the desktop extension.

Copy a starter config from examples/ and set your VM paths:

cp examples/smalltalk-mcp-ollama.json smalltalk-mcp.json
# Edit vm.binary and vm.image to match your install

The VM auto-starts on first use — no manual launch needed. Token auth is handled automatically.

See examples/ for Anthropic, OpenAI, xAI, and MQTT variants.

3. Configure Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS):

{
  "mcpServers": {
    "smalltalkAgent": {
      "command": "uv",
      "args": ["run", "/path/to/ClaudeSmalltalk/smalltalk_agent_mcp.py"],
      "env": {
        "SMALLTALK_MCP_CONFIG": "/path/to/smalltalk-mcp.json"
      }
    }
  }
}

Requires Python 3.10+. Dependencies (httpx) are resolved automatically by uv. Install uv if you don't have it by following the official installation instructions there (for example via your package manager where available). If you choose to use an install script, review it first and follow any checksum or signature verification steps described in the uv documentation.

Alternatively, if you prefer not to use uv, you can use python3 as the command — but you'll need to install httpx yourself (pip install httpx or pip3 install httpx). For MQTT transport, also: pip install paho-mqtt.

4. Verify It Works

Open Claude Desktop and ask:

"List all Smalltalk classes that start with String"

Available Tools

Claude Desktop (1 tool)

Tool	Description
smalltalk_task	Delegate any Smalltalk task to a locally-configured LLM. No source code leaves your machine.

VM Tools (14, available to the agent)

Tool	Description
smalltalk_evaluate	Execute Smalltalk code and return result
smalltalk_browse	Get class metadata (superclass, ivars, methods)
smalltalk_method_source	View source code of a method
smalltalk_define_class	Create or modify a class definition
smalltalk_define_method	Add or update a method
smalltalk_delete_method	Remove a method from a class
smalltalk_delete_class	Remove a class from the system
smalltalk_list_classes	List classes matching a prefix
smalltalk_hierarchy	Get superclass chain
smalltalk_subclasses	Get immediate subclasses
smalltalk_list_categories	List all system categories
smalltalk_classes_in_category	List classes in a category
smalltalk_save_image	Save the current image in place
smalltalk_save_as_new_version	Save image/changes as next version number

All 14 tools are also available directly via the st CLI (openclaw/smalltalk.py).

Configuration Reference

Supported LLM Providers

Provider	API	Cost	Config key
Ollama	/v1/chat/completions	Free (local)	"provider": "ollama"
Anthropic	/v1/messages (httpx)	Paid	"provider": "anthropic"
OpenAI	/v1/chat/completions	Paid	"provider": "openai"
xAI	/v1/chat/completions	Paid	"provider": "xai"

All providers use httpx (included as a dependency) — no additional packages to install.

Transport Options

Transport	How	Use Case
tcp	Token-authenticated TCP to Squeak VM	Recommended — VM is its own server
mqtt	MQTT broker to remote image	Remote images, Cuis with MQTT handler

tcp is the default. The Squeak VM runs MCPTcpTransport and listens on a local port. The agent auto-starts the VM on first use, generates a UUID token, and connects per-request with JSON-RPC + token auth.

mqtt connects through an MQTT broker. Used for remote images or Cuis with the MQTT LLM handler.

macOS Permissions

macOS Transparency, Consent, and Control (TCC) restricts which directories applications can access.

Safe locations (no extra permissions needed):

• /Applications/ — recommended for VM and image files
• ~/ (home directory root) — works for config files

Restricted locations (will cause errors):

• ~/Documents/, ~/Desktop/, ~/Downloads/

Other Integration Options

Option	Architecture	Guide
OpenClaw	Telegram/Discord ↔ OpenClaw ↔ Squeak	OPENCLAW-SETUP.md

Security

The extension only connects to a local Smalltalk image over TCP (localhost only). No source code is sent to cloud APIs when using Ollama.

With Ollama + TCP transport, no Smalltalk source code leaves your machine.

Dual security audit details: SECURITY.md

Files

File	Description
Claude.SmalltalkInterface.mcpb	Desktop extension — double-click to install
CLAUDE-README-MCPB.md	Setup guide bundled with the extension
smalltalk_agent_mcp.py	MCP server (stdio JSON-RPC for Claude Desktop)
smalltalk_agent.py	Agent with tool-calling loop, TcpBridge + MqttBridge
openclaw/smalltalk.py	st CLI — direct TCP access to all 14 tools
openclaw/mqtt_bridge.py	MQTT CLI bridge for Cuis/remote images
smalltalk-mcp-example.json	Starter config — copy and edit
SKILL.md	Drag into Claude Desktop for Smalltalk best practices
MCP-Server-Squeak.st	MCP server fileIn for Squeak 6.0 (TCP transport)
MCP-Server.pck.st	MCP server package for Cuis
examples/	Config examples for all providers and transports

License

MIT License — see LICENSE