backend/agent_instance.py

import sys
import os

# ✅ Add src to Python path
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..", "src")))

from txagent.txagent import TxAgent

def init_agent():
    # ✅ Use Hugging Face persistent storage
    base_dir = "/data"
    model_cache_dir = os.path.join(base_dir, "hf_cache")
    tool_cache_dir = os.path.join(base_dir, "tool_cache")

    # ✅ Ensure the folders exist
    os.makedirs(model_cache_dir, exist_ok=True)
    os.makedirs(tool_cache_dir, exist_ok=True)

    # ✅ Set environment variables so models stay cached after restart
    os.environ["TRANSFORMERS_CACHE"] = model_cache_dir
    os.environ["HF_HOME"] = model_cache_dir

    # ✅ Paths to model + tool definitions
    model_name = "mims-harvard/TxAgent-T1-Llama-3.1-8B"
    rag_model_name = "mims-harvard/ToolRAG-T1-GTE-Qwen2-1.5B"
    tool_files_dict = {
        "new_tool": os.path.join(tool_cache_dir, "new_tool.json")
    }

    # ✅ Init agent with config
    agent = TxAgent(
        model_name=model_name,
        rag_model_name=rag_model_name,
        tool_files_dict=tool_files_dict,
        force_finish=True,
        enable_checker=True,
        step_rag_num=10,
        seed=100,
        additional_default_tools=[]
    )
    agent.init_model()
    return agent