CodeAgent

An Elixir library for AI-powered code modifications using Claude Opus 4 through LangChain.

Features

• 🤖 Natural language code modifications using Claude AI
• 📁 Directory-scoped file operations with sandboxing
• 🔄 Conversation history for context-aware interactions
• 📝 JSON-based operation format for reliable modifications
• 🧪 Comprehensive test suite with unit and integration tests
• ⚙️ Idempotent configuration management with ConfigAgent
• 📜 Single-file scripts runnable via curl

Installation

Add code_agent to your list of dependencies in mix.exs:

def deps do
  [
    {:code_agent, "~> 0.1.0"}
  ]
end

Configuration

Set your Anthropic API key as an environment variable:

export ANTHROPIC_API_KEY="your-api-key"

Usage

Basic Setup

# Create an agent for a directory
agent = CodeAgent.new(base_dir: "/path/to/your/project")

Execute Code Modifications

# Modify code with natural language instructions
{:ok, result, agent} = CodeAgent.execute(agent,
  "Add error handling to all database queries",
  ["lib/my_app/repo", "lib/my_app/queries.ex"]  # Reference files/dirs
)

# Result includes:
# - analysis: Claude's understanding of the task
# - operations: List of file modifications performed
# - summary: Human-readable summary
# - questions: Any clarifying questions

Ask Questions About Code

# Analyze code without modifications
{:ok, answer, agent} = CodeAgent.ask(agent,
  "What patterns are used in the authentication system?",
  ["lib/my_app/auth/"]
)

Conversation Context

The agent maintains conversation history between calls:

# First, analyze the code
{:ok, _, agent} = CodeAgent.ask(agent,
  "What does this module do?",
  ["lib/calculator.ex"]
)

# Then ask a follow-up question
{:ok, response, agent} = CodeAgent.ask(agent,
  "How could we improve its performance?",
  []  # No need to re-specify files
)

ConfigAgent - Idempotent Configuration Management

ConfigAgent specializes in ensuring configuration files match specifications, perfect for DevOps automation:

spec = %{
  instructions: "Set up Kubernetes deployment files",
  templates: %{
    "namespace" => "apiVersion: v1\nkind: Namespace\n..."
  },
  files: [
    %{
      path: "k8s/namespace.yaml",
      description: "Kubernetes namespace for the application",
      template: "namespace",  # Reference to template above
      format: "yaml"
    }
  ]
}

# Ensure configuration matches spec (idempotent)
{:ok, results} = CodeAgent.ConfigAgent.ensure_configuration(".", spec)

# Check compliance without making changes
compliance = CodeAgent.ConfigAgent.check_compliance(".", spec)

Run Scripts via Curl

Create single-file Elixir scripts that can be executed directly:

# Run Kubernetes setup script
curl -sSL https://raw.githubusercontent.com/u2i/code_agent/main/examples/kubernetes_setup.exs | \
  ANTHROPIC_API_KEY=your-key elixir - --app-name myapp --port 3000

# Check compliance without changes
curl -sSL https://raw.githubusercontent.com/u2i/code_agent/main/examples/kubernetes_setup.exs | \
  ANTHROPIC_API_KEY=your-key elixir - --check

Operation Format

The library uses a JSON format for modifications:

{
  "operations": [
    {
      "type": "edit",
      "file": "lib/example.ex",
      "find": "old_function()",
      "replace": "new_function()"
    },
    {
      "type": "create",
      "file": "lib/new_file.ex",
      "content": "defmodule NewFile do\n  # content\nend"
    }
  ]
}

Testing

# Run unit tests only
mix test

# Run all tests including Claude API integration tests
ANTHROPIC_API_KEY=your-key mix test --include integration

Safety Features

• All file operations are sandboxed to the specified base directory
• Path traversal attempts are blocked
• File modifications use exact string matching to prevent unintended changes

Dependencies

• LangChain - LLM framework
• Plug Cowboy - HTTP server (optional)
• Jason - JSON parser

License

This project is licensed under the MIT License - see the LICENSE file for details.