claude_code_quickstart

Claude Code CLI Quickstart

This example shows how to use the Claude Code CLI as the LLM backend for OpenEvolve. No API keys are needed — authentication uses the CLI's existing OAuth session.

Prerequisites

1. Install Claude Code CLI:

   npm install -g @anthropic-ai/claude-code

2. Authenticate:

   claude login

3. Install OpenEvolve:

   pip install openevolve

Run

python openevolve-run.py \
  examples/claude_code_quickstart/initial_program.py \
  examples/claude_code_quickstart/evaluator.py \
  --config examples/claude_code_quickstart/config.yaml \
  --iterations 50

How It Works

The config.yaml sets provider: "claude_code" which routes all LLM calls through the claude -p subprocess instead of the OpenAI-compatible API. The CLI handles authentication, model selection, and billing.

Key Config Options

Field	Description	Default
provider	Set to "claude_code" to use the CLI backend	"openai"
name	Claude model name (sonnet, haiku, opus)	"sonnet"
max_budget_usd	Per-call spending cap in USD	1.0
timeout	CLI timeout in seconds	300
retries	Number of retry attempts on failure	3
retry_delay	Seconds between retries	5

Ensemble Example

You can mix Claude models in an ensemble, just like with OpenAI models:

llm:
  provider: "claude_code"
  models:
    - name: "sonnet"
      weight: 0.8
      max_tokens: 16000
    - name: "haiku"
      weight: 0.2
      max_tokens: 8000

Programmatic Usage

You can also inject the Claude Code backend at runtime without modifying config files:

from openevolve.llm.claude_code import init_claude_code_client

for model_cfg in config.llm.models:
    model_cfg.init_client = init_claude_code_client