Create llm_utils.py

llm_utils.py

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+# llm_utils.py
+import os
+from openai import OpenAI
+
+
+# Option 1 (recommended): set OPENAI_API_KEY in Hugging Face Secrets
+API_KEY = os.getenv("OPENAI_API_KEY", "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")
+
+
+client = OpenAI(api_key=API_KEY)
+
+
+def explain_savings_plan(payload: dict) -> str:
+    """
+    Uses a small LLM model to turn numeric savings plan outputs into a
+    short, plain-English explanation.
+
+    The LLM:
+    - MUST NOT invent new numbers
+    - Only rephrases the fields in payload
+    - Does not change the calculation, only explains it
+    """
+
+    system_prompt = """
+You are an AI assistant that explains mortgage down-payment savings plans.
+You MUST NOT invent any new numbers.
+Use ONLY the fields provided in the JSON payload.
+Write 2–3 short sentences that:
+  1) State what the user is trying to achieve (reach a down payment).
+  2) Explain why this recommended monthly savings amount makes sense.
+  3) Mention the timeline (years and months).
+Be neutral, clear, and non-promotional.
+    """.strip()
+
+    # We send the raw payload as JSON text in the user message.
+    user_content = f"Here is the JSON for this user's plan: {payload}"
+
+    try:
+        completion = client.chat.completions.create(
+            model="gpt-4.1-mini",
+            messages=[
+                {"role": "system", "content": system_prompt},
+                {"role": "user", "content": user_content},
+            ],
+            max_tokens=200,
+            temperature=0.3,
+        )
+        explanation = completion.choices[0].message.content.strip()
+        return explanation
+    except Exception as e:
+        # Fallback if LLM fails
+        return (
+            "We calculated your recommended monthly savings based on your home budget, "
+            "target down payment %, current savings, and chosen timeline. "
+            "The amount spreads your remaining down-payment need over the available months, "
+            "adding estimated closing costs and subtracting expected interest earnings."
+        )