signal-scanner — rule-based stock/crypto screener with alerts

Define a watchlist and a ruleset (plain YAML); the scanner pulls market data, computes indicators, and tells you which symbols match — on the console, in Telegram, or from any MCP host (Claude Desktop / Claude Code).

Built once, reskinned per client: swap watchlist.txt + rules.yaml, ship.

Why it's different

• Keyless by default. Market data via yfinance — no API key. Works for stocks, ETFs, FX (EURUSD=X) and crypto (BTC-USD). Demo it anywhere.
• No-code rules. Clients edit rules.yaml (conditions on indicators) — never the code.
• Honest signals. Indicators are computed from closed bars (no look-ahead); a symbol with no data is reported, never faked.
• Delivery that degrades. Telegram alerts when a bot token is set; otherwise prints to console. The scanner always runs.
• Three surfaces, one engine. CLI (one-shot or --watch), Telegram push, and an MCP scan tool.

Indicators & rules

Indicators per symbol: price, pct_change, rsi, sma_fast, sma_slow, sma_cross (golden/death), vol_ratio (vs 20-day avg), pct_from_52w_high, pct_from_52w_low.

A rule fires when all its conditions are true:

rules:
  - name: oversold
    when:
      - {indicator: rsi, op: "<", value: 30}
  - name: volume_spike_up
    when:
      - {indicator: vol_ratio, op: ">", value: 2.0}
      - {indicator: pct_change, op: ">", value: 1.0}

Quickstart

pip install -r requirements.txt
PYTHONUTF8=1 python tests/test_smoke.py     # deterministic, no network — proves the engine

python -m signal_scanner                    # scan the watchlist once, print matches
python -m signal_scanner AAPL MSFT BTC-USD  # scan ad-hoc symbols
python -m signal_scanner --watch            # loop every SCAN_INTERVAL_S (default 15m)
python -m signal_scanner --notify           # also push matches to Telegram (if configured)

Telegram (optional)

Create a bot with @BotFather, get the token; get your chat id from @userinfobot. Then in .env:

TELEGRAM_BOT_TOKEN=...
TELEGRAM_CHAT_ID=...

As an MCP server (Claude Desktop)

{
  "signal-scanner": {
    "command": "python",
    "args": ["-m", "signal_scanner.server"],
    "cwd": "C:/path/to/signal-scanner"
  }
}

Use the full path to your Python (e.g. the one where you ran pip install -r requirements.txt) if python isn't on PATH. Then ask Claude: "Run my scanner" or "Any signals on NVDA and BTC-USD?" — it calls the scan tool.

Configuration

All knobs in config.py / .env (see .env.example): RSI period, SMA fast/slow, volume window, lookback, poll interval, data backend, Telegram. A client reskin is usually just watchlist.txt + rules.yaml.

Architecture

watchlist.txt ─┐
               ├─ scanner.py ─ data.py(yfinance) ─ indicators.py ─ rules.py(rules.yaml)
rules.yaml ────┘                                                         │
                                                  signals ──> console / Telegram / MCP `scan`

Reuses the mcp-factory contract (Result, formatting, cache) so it composes with the rest of the catalog.

License

MIT.