Joeven — Learn Autonomous AI Agents

← LessonReAct: Thought, Action, ObservationJoeven

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import json
import re

TOOLS = {
    "get_weather": lambda city: {"city": city, "sky": "rain", "temp_c": 12},
    "finish": lambda answer: {"final": answer},
}

def parse_react(text):
    thought = re.search(r"Thought:\s*(.*)", text)
    action = re.search(r"Action:\s*(\w+)", text)
    args = re.search(r"Action Input:\s*(\{.*\})", text)
    return {
        "thought": thought.group(1).strip() if thought else "",
        "action": action.group(1) if action else None,
        "args": json.loads(args.group(1)) if args else {},
    }

def fake_model(scratchpad):
    if not scratchpad:
        return chr(10).join([
            "Thought: I should check the weather before advising.",
            "Action: get_weather",
            'Action Input: {"city": "Paris"}',
        ])
    obs = scratchpad[-1]["observation"]
    if obs.get("sky") == "rain":
        ans = "Take an umbrella in Paris (12C, rain)."
    else:
        ans = "No umbrella needed."
    return chr(10).join([
        "Thought: Use the observation, not a guess.",
        "Action: finish",
        "Action Input: " + json.dumps({"answer": ans}),
    ])

scratchpad = []
for step in range(1, 6):
    parsed = parse_react(fake_model(scratchpad))
    obs = TOOLS[parsed["action"]](**parsed["args"])
    rec = {
        "thought": parsed["thought"],
        "action": parsed["action"],
        "args": parsed["args"],
        "observation": obs,
    }
    scratchpad.append(rec)
    print("step", step, rec["action"], rec["args"])
    print(" obs", rec["observation"])
    if parsed["action"] == "finish":
        break

print("ANSWER", scratchpad[-1]["observation"]["final"])

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