Signals

STOCH — Stochastic Oscillator

Compare the close to its recent range with %K and %D outputs.

What it is

Stochastic Oscillator compares the latest close to the recent trading range and returns two lines: fast %K and smoothed %D.

When to use it

Looking for overbought or oversold reversals inside well-defined ranges.
Watching %K and %D crossovers as short-term momentum timing signals.
Confirming exhaustion after a sharp multi-day move.

The maths

%K = 100 × (close - lowest_low(N)) / (highest_high(N) - lowest_low(N)), %D = SMA(3) of %K The default N is 14.

What it tells you

Above 80 is overbought and below 20 is oversold. %K crossing above %D is a buy signal, while crossing below is a sell signal, and it is generally more reliable in ranging markets than in strong trends.

REST example

python

import os
import requests

response = requests.get(
  'https://api.financedata.com/v1/signals/STOCH/SPY',
  params={'start_date': '2025-01-01', 'end_date': '2025-04-30', 'k_period': 14, 'd_period': 3},
  headers={'X-API-Key': os.environ['FDA_KEY']},
  timeout=30,
)
response.raise_for_status()
print(response.json())

MCP example

Tool call body

{
"name": "run_signals",
"arguments": {
  "symbols": ["SPY"],
  "signal_names": ["STOCH"],
  "start_date": "2025-01-01",
  "end_date": "2025-04-30",
  "signal_parameters": {
    "STOCH": { "k_period": 14, "d_period": 3 }
  }
}
}

Because STOCH returns both k and d, MCP batch output is useful when you want the agent to reason about crossovers directly.

Agent prompt that triggers it

Compute STOCH for SPY and tell me whether the latest %K/%D configuration looks overbought, oversold, or neutral.