indicator-scanner

Create a multi-symbol indicator scanner that screens stocks by technical conditions.

Arguments

Parse $ARGUMENTS as: scan-type watchlist

• $0 = scan type (e.g., rsi-oversold, rsi-overbought, ema-crossover, supertrend-buy, supertrend-sell, macd-crossover, adx-trending, custom). Default: rsi-oversold
• $1 = watchlist (e.g., nifty50, banknifty, custom). Default: nifty50

If no arguments, ask the user what they want to scan for.

Instructions

1. Read the indicator-expert rules for reference
2. Create workspace/indicators/scanners/ (mkdir -p)
3. Write the script to workspace/indicators/scanners/{scan_type}_{watchlist}.py
4. The script must:
   • Load .env from project root
   • Define the watchlist (predefined or custom)
   • Fetch data for each symbol via client.history()
   • Compute indicator(s) using openalgo.ta
   • Check the scan condition
   • Print results as a formatted table
   • Save results to CSV
   • Optionally get real-time LTP via client.quotes() for current values

Scan Logic Pattern

results = []
for symbol in watchlist:
    df = fetch_data(symbol, exchange, interval)
    close = df["close"]

    # Compute indicator
    rsi = ta.rsi(close, 14)
    current_rsi = rsi.iloc[-1]

    # Check condition
    if current_rsi < 30:  # RSI oversold
        results.append({
            "symbol": symbol,
            "ltp": close.iloc[-1],
            "rsi": current_rsi,
            "signal": "OVERSOLD",
        })

# Print table
df_results = pd.DataFrame(results)
print(df_results.to_string(index=False))
df_results.to_csv(script_dir / f"{scan_type}_results.csv", index=False)

Predefined Scan Types

Predefined Watchlists

NIFTY 50 (nifty50)

NIFTY50 = [
    "ADANIENT", "ADANIPORTS", "APOLLOHOSP", "ASIANPAINT", "AXISBANK",
    "BAJAJ-AUTO", "BAJFINANCE", "BAJAJFINSV", "BPCL", "BHARTIARTL",
    "BRITANNIA", "CIPLA", "COALINDIA", "DIVISLAB", "DRREDDY",
    "EICHERMOT", "GRASIM", "HCLTECH", "HDFCBANK", "HDFCLIFE",
    "HEROMOTOCO", "HINDALCO", "HINDUNILVR", "ICICIBANK", "INDUSINDBK",
    "INFY", "ITC", "JSWSTEEL", "KOTAKBANK", "LT",
    "M&M", "MARUTI", "NESTLEIND", "NTPC", "ONGC",
    "POWERGRID", "RELIANCE", "SBILIFE", "SBIN", "SUNPHARMA",
    "TCS", "TATACONSUM", "TATAMOTORS", "TATASTEEL", "TECHM",
    "TITAN", "ULTRACEMCO", "UPL", "WIPRO",
]

Bank NIFTY (banknifty)

BANKNIFTY = [
    "HDFCBANK", "ICICIBANK", "KOTAKBANK", "AXISBANK", "SBIN",
    "INDUSINDBK", "BANKBARODA", "FEDERALBNK", "PNB", "IDFCFIRSTB",
    "BANDHANBNK", "AUBANK",
]

Output Format

Symbol     LTP      RSI(14)  Signal
------     ---      -------  ------
SBIN       769.60   28.4     OVERSOLD
TATASTEEL  142.30   25.1     OVERSOLD
COALINDIA  385.00   29.7     OVERSOLD

Scan: RSI Oversold (<30) | Watchlist: NIFTY 50 | Date: 2025-02-28
Found 3 / 50 symbols matching condition
Results saved to: scanners/rsi_oversold/rsi_oversold_results.csv

Example Usage

/indicator-scanner rsi-oversold nifty50 /indicator-scanner ema-crossover banknifty /indicator-scanner supertrend-buy nifty50 /indicator-scanner volume-spike nifty50 /indicator-scanner custom

Verify before calling it done

A scanner that returns nothing looks identical to a scanner that is broken. Prove it works before trusting a result:

• Seed a known positive. Pick a symbol you have already confirmed meets the condition (chart it first) and check the scan finds it. An empty result set is only meaningful once you have seen a non-empty one.
• Invert the condition. Flip rsi < 30 to rsi > 30 and confirm the result count roughly complements. If both return zero, the data is not loading and the condition is never the problem.
• Count the universe actually scanned, not the universe requested. Log scanned / requested. Symbols dropped for missing data, a wrong exchange, or a delisted ticker vanish silently and quietly shrink the result set.
• Check the last bar is today's. Scanning on stale history produces yesterday's signals with no error. Print df.index[-1] for one symbol and compare against the current session.
• Confirm no NaN leakage. A symbol with fewer bars than the indicator period yields NaN, and NaN < 30 is False — so short-history symbols are silently excluded rather than flagged. Report them separately.
• Exchange is correct per symbol. Index underlyings use NSE_INDEX/BSE_INDEX; stocks use NSE/BSE. Passing the wrong one returns no data rather than an error. See docs/prompt/symbol-format.md.

Lookahead check: a scan run at 11:00 must not use the completed daily candle. If the result changes when you re-run the same scan against a date-truncated dataset, the condition is reading a bar that had not closed.

Where to write files

Default location is workspace/indicators/scanners/ in the repo root. Create it immediately before writing — it does not exist on a fresh clone:

mkdir -p workspace/indicators/scanners

Name the file <indicator>_<symbol>_<interval>.py so the folder stays scannable as it grows, e.g. workspace/indicators/scanners/rsi_oversold_nifty50.py.

Rendered output goes to workspace/indicators/output/ under the same stem, keeping the script and its artifact associated without cluttering the source folder:

workspace/indicators/scanners/rsi_oversold_nifty50.py  ->  workspace/indicators/output/rsi_oversold_nifty50.csv

If the user names a different folder, use it and keep the same layout beneath it. Note that only workspace/ is gitignored (except its readme), so writing elsewhere inside the repo produces tracked files — mention that before doing it.

Run from the repo root:

uv run --group analysis python workspace/indicators/scanners/rsi_oversold_nifty50.py