Smalltalk Skill

Execute Smalltalk code and browse live Squeak/Cuis images via MCP.

Prerequisites

Get the ClaudeSmalltalk repo first:

git clone https://github.com/CorporateSmalltalkConsultingLtd/ClaudeSmalltalk.git

This repo contains:

• MCP server code for Squeak (MCP-Server-Squeak.st)
• Setup documentation (SQUEAK-SETUP.md, CLAWDBOT-SETUP.md)
• This Clawdbot skill (clawdbot/)

Setup

1. Set up Squeak with MCP server — see SQUEAK-SETUP.md
2. Configure Clawdbot — see CLAWDBOT-SETUP.md

Usage

# Check setup
python3 smalltalk.py --check

# Evaluate code
python3 smalltalk.py evaluate "3 factorial"
python3 smalltalk.py evaluate "Date today"

# Browse a class
python3 smalltalk.py browse OrderedCollection

# View method source (instance side)
python3 smalltalk.py method-source String asUppercase

# View method source (class side)
python3 smalltalk.py method-source "MCPServer class" version
python3 smalltalk.py method-source MCPServer version --class-side

# List classes (with optional prefix filter)
python3 smalltalk.py list-classes Collection

# Get class hierarchy
python3 smalltalk.py hierarchy OrderedCollection

# Get subclasses  
python3 smalltalk.py subclasses Collection

# List all categories
python3 smalltalk.py list-categories

# List classes in a category
python3 smalltalk.py classes-in-category "Collections-Sequenceable"

# Define a new class
python3 smalltalk.py define-class "Object subclass: #Counter instanceVariableNames: 'count' classVariableNames: '' poolDictionaries: '' category: 'MyApp'"

# Define a method
python3 smalltalk.py define-method Counter "increment
    count := (count ifNil: [0]) + 1.
    ^ count"

# Delete a method
python3 smalltalk.py delete-method Counter increment

# Delete a class
python3 smalltalk.py delete-class Counter

Operating Modes

Playground (Default)

Stock image, ephemeral. Changes are discarded when daemon stops. User says: "load Smalltalk skill" or "invoke Smalltalk" — no special flags.

# Start playground daemon
nohup python3 smalltalk-daemon.py start > /tmp/daemon.log 2>&1 &

Dev Mode

User supplies their own image/changes pair. Changes persist across sessions. User says: "load Smalltalk skill in dev mode with ~/MyProject.image"

# Start dev daemon with custom image
nohup python3 smalltalk-daemon.py start --dev --image ~/MyProject.image > /tmp/daemon.log 2>&1 &

Dev mode sets SMALLTALK_DEV_MODE=1 so the MCP server keeps the .changes file (instead of redirecting to /dev/null). The supplied image must have a matching .changes file alongside it.

Common Commands

# Check status
python3 smalltalk.py --daemon-status

# Stop daemon
python3 smalltalk-daemon.py stop

# Restart in dev mode
python3 smalltalk-daemon.py restart --dev --image ~/MyProject.image

Commands

Command	Description
--check	Verify VM/image paths and dependencies
--daemon-status	Check if daemon is running
--debug	Debug hung system (sends SIGUSR1, captures stack trace)
evaluate <code>	Execute Smalltalk code, return result
browse <class>	Get class metadata (superclass, ivars, instance methods and classMethods)
method-source <class> <selector> [--class-side]	View method source code (supports "Class class" syntax or --class-side flag)
define-class <definition>	Create or modify a class
define-method <class> <source>	Add or update a method
delete-method <class> <selector>	Remove a method
delete-class <class>	Remove a class
list-classes [prefix]	List classes, optionally filtered
hierarchy <class>	Get superclass chain
subclasses <class>	Get immediate subclasses
list-categories	List all system categories
classes-in-category <cat>	List classes in a category
explain <code>	Explain Smalltalk code (requires ANTHROPIC_API_KEY or OPENAI_API_KEY)
explain-method <class> <sel> [--class-side] [--source <code>]	Fetch method from image and explain it (or use --source/--source-file/--source-stdin to bypass daemon)
audit-comment <class> <sel> [--class-side] [--source <code>]	Audit method comment vs implementation (or use --source/--source-file/--source-stdin to bypass daemon)
audit-class <class>	Audit all methods in a class (instance + class side)
generate-sunit <targets> [--force] [--class-name <name>]	Generate SUnit tests for methods and file into image

Environment Variables

Variable	Description
SQUEAK_VM_PATH	Path to Squeak/Cuis VM executable
SQUEAK_IMAGE_PATH	Path to Smalltalk image with MCP server
ANTHROPIC_API_KEY	API key for Anthropic Claude (preferred for LLM tools)
ANTHROPIC_MODEL	Anthropic model (default: claude-opus-4-20250514)
OPENAI_API_KEY	API key for OpenAI (fallback for LLM tools)
OPENAI_MODEL	OpenAI model (default: gpt-4o)
LLM_PROVIDER	Force LLM provider: anthropic or openai (auto-detected if not set)

Using with Claude Code (MCP mode)

When Claude Code has a live Smalltalk image connected via MCP, explain-method and audit-comment can use pre-fetched source code instead of requiring a running daemon. Use --source, --source-file, or --source-stdin to pass the method source directly:

# Inline source (fetched via MCP, passed on command line)
python3 smalltalk.py explain-method SmallInteger + --source "+ aNumber <primitive: 1> ^ super + aNumber"

# Source from a file
python3 smalltalk.py audit-comment Integer factorial --source-file /tmp/factorial.st

# Source piped via stdin
echo "printString ^ self printStringLimitedTo: 50000" | python3 smalltalk.py explain-method Object printString --source-stdin

The three source flags are mutually exclusive. When none is provided, the daemon is used as before.

Generating SUnit Tests

The generate-sunit command uses an LLM to generate SUnit test cases for Smalltalk methods and files them directly into the running image:

# Generate tests for a single method
python3 smalltalk.py generate-sunit "String>>asUppercase"

# Generate tests for multiple methods
python3 smalltalk.py generate-sunit "Random>>next" "Random>>nextInt:" "Random>>seed:"

# Generate tests for an entire class (all instance methods)
python3 smalltalk.py generate-sunit "OrderedCollection"

# Generate tests for class-side methods
python3 smalltalk.py generate-sunit "Date class>>today"

# Custom test class name
python3 smalltalk.py generate-sunit "String>>asUppercase" --class-name MyStringTests

# Overwrite existing test class
python3 smalltalk.py generate-sunit "String>>asUppercase" --force

# Run the generated tests
python3 smalltalk.py evaluate "StringGeneratedTest buildSuite run printString"

The generated TestCase uses standard SUnit assertions (assert:, assert:equals:, deny:, should:raise:) and is filed into a GeneratedSUnit-* category.

Notes

• Requires xvfb for headless operation on Linux servers
• Uses Squeak 6.0 MCP server (GUI stays responsive if display available)
• saveImage intentionally excluded for safety
• MCPServer version 7+ required (v7 adds class-side method support)
• Playground mode: ephemeral, .changes → /dev/null
• Dev mode: persistent, .changes kept, requires --dev --image PATH