My Code With Openrouter api is not working

I'm trying to automate intraday financial analysis using OpenRouter's free models. My Python script rotates through several LLM endpoints, sending a prompt about a stock's symbol, change, and closing price. If any model fails (API error, empty response, etc.), it tries the next one; if all fail, it falls back to a rule-based analysis.

I've set my OpenRouter API key in the environment variable, but I'm unsure if my error handling and rotation are robust. Also, are there best practices for passing custom headers or for prompt formatting with financial data? Is using the provided rotation strategy and fallbacks a sound approach for clean, concise intraday financial summaries?

Here is my code (for reference):

import os
import requests
import json

# ================================================================
# ENV-BASED API KEY (YOU MUST SET IN TERMINAL or ~/.zshrc)
# ================================================================

OPENROUTER_API_KEY = os.getenv("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", "")

OPENROUTER_URL = "https://openrouter.ai/api/v1/chat/completions"

# ==========================
# MULTI-MODEL ROTATION LIST
# ==========================

FREE_MODELS = [
    "x-ai/grok-4.1-fast:free",
    "z-ai/glm-4.5-air:free",
    "deepseek/deepseek-chat-v3-0324:free",
    "deepseek/deepseek-r1-0528:free",
    "qwen/qwen3-coder:free",
    "nvidia/nemotron-nano-12b-v2-vl:free",
    "google/gemma-3-27b-it:free",
]


# ================================================================
# RULE-BASED FALLBACK
# ================================================================

def fallback_insight(symbol, change, close_price):
    direction = "up" if change > 0 else "down" if change < 0 else "flat"
    return (
        f"[Fallback] {symbol}: price is {direction} ({change:+.2f}) at {close_price:.2f}. "
        f"LLM unavailable, using rule-based analysis."
    )


# ================================================================
# MAIN FUNCTION (called from Pathway)
# ================================================================

def generate_market_insight(symbol, change, close_price):
    print("\n=====================================================")
    print(f"[DEBUG] LLM call triggered for {symbol}")
    print("=====================================================\n")

    if not OPENROUTER_API_KEY or not OPENROUTER_API_KEY.startswith("sk-or-"):
        print("[ERROR] Missing or invalid OPENROUTER_API_KEY")
        return fallback_insight(symbol, change, close_price)

    prompt = f"""
You are a professional financial market analyst.
Write a short intraday analysis in clean, concise English.

Instrument:
- Symbol: {symbol}
- Change: {change:+.2f}
- Last Close: {close_price:.2f}

Rules:
- Trend should be based on magnitude and direction of move.
- Mention risk (low/medium/high).
- Explain if the move is normal intraday noise or meaningful.
- Write 5–7 bullet points.
- Must be unique for this specific stock. No generic filler.
"""

    # Try each model one by one
    for model in FREE_MODELS:
        print(f"\n[DEBUG] Trying model: {model}")

        body = {
            "model": model,
            "messages": [
                {"role": "user", "content": prompt.strip()}
            ],
            "max_tokens": 220,
            "temperature": 0.9,
            "top_p": 0.9,
        }

        headers = {
            "Authorization": f"Bearer {OPENROUTER_API_KEY}",
            "Content-Type": "application/json",
            "HTTP-Referer": "http://localhost",
            "X-Title": "GGSIPU-Financial-Monitoring",
        }

        try:
            print("[DEBUG] Sending request to OpenRouter...")
            resp = requests.post(OPENROUTER_URL, json=body, headers=headers, timeout=40)
            print(f"[DEBUG] HTTP Status = {resp.status_code}")

            if resp.status_code != 200:
                print("[ERROR] Model failed:", model, resp.text[:180])
                continue

            data = resp.json()

            if "error" in data:
                print("[ERROR] API Model Error:", data["error"])
                continue

            content = data["choices"][0]["message"]["content"]
            if not content:
                print("[ERROR] Model returned empty content.")
                continue

            print(f"[DEBUG] SUCCESS with model: {model}")
            return content.strip()

        except Exception as e:
            print(f"[EXCEPTION] Model crashed: {model} → {repr(e)}")
            continue

    print("[ERROR] ALL MODELS FAILED → fallback triggered.")
    return fallback_insight(symbol, change, close_price)