feat(models): Claude CLI provider for Pro/Max subscription users

[mhooooo]

Summary

Adds ClaudeCLIModel — a new LangChain BaseChatModel provider that wraps the Claude Code CLI in --print mode. This enables DeerFlow users with a Claude Pro or Max subscription to run DeerFlow without an API key at zero additional API cost.

Problem

Currently, using Claude with DeerFlow requires either:

• An ANTHROPIC_API_KEY (pay-per-token), or
• The existing ClaudeChatModel with OAuth tokens — which returns 400 invalid_request_error because OAuth tokens are scoped to Claude Code sessions and don't work with direct Messages API calls

Many users already have Claude Pro ($20/mo) or Max ($100-200/mo) subscriptions with generous usage included. There's no way to leverage these subscriptions with DeerFlow today.

Solution

ClaudeCLIModel spawns claude --print --output-format json as a subprocess, which authenticates using the CLI's built-in auth (claude /login). The CLI handles token management, refresh, and all API communication internally.

Config:

models:
  - name: claude-sonnet
    display_name: Claude Sonnet 4.6 (Max subscription)
    use: deerflow.models.claude_cli_provider:ClaudeCLIModel
    model: claude-sonnet-4-6
    max_tokens: 16384

Prerequisites:

curl -fsSL https://claude.ai/install.sh | bash
claude /login

Features

• Implements BaseChatModel — works with LangGraph agents out of the box
• bind_tools() support — tool schemas injected into system prompt for LangGraph compatibility
• Parses JSON output including token usage, cost, duration, and session metadata
• Filters interfering env vars (CLAUDECODE, NODE_OPTIONS, etc.) from subprocess
• Configurable: model, max_turns, permission_mode, allowed/disallowed tools, timeout
• Auto-discovers claude CLI from $PATH or well-known install locations

Tested with

• Claude Sonnet 4.6 + Max subscription (5x rate limit tier)
• DeerFlow lead agent with full middleware chain
• macOS (Apple Silicon)

Test plan

• Direct invocation: ClaudeCLIModel.invoke([HumanMessage("What is 2+2?")]) → "4"
• LangGraph integration: Full lead agent conversation via /threads/{id}/runs/stream
• Tool binding: bind_tools() with DeerFlow's built-in tools (bash, file ops, web search)
• Error handling: timeout, CLI not found, non-zero exit code
• Unit tests (happy to add if maintainers want them in this PR)

🤖 Generated with Claude Code

[CLAassistant]

All committers have signed the CLA.

[WillemJiang]

@mhooooo, thanks for the contribution. You need to sign the CLA by clicking the button before we can review it.
Please submit the unit test at the same time.