humanizer_scroll

Simulates human-like scrolling behavior in browsers by generating natural acceleration and deceleration patterns using easeInOutQuad velocity distribution.

Instructions

Scroll with natural acceleration/deceleration using easeInOutQuad velocity distribution. Dispatches multiple wheel events to simulate human scroll behavior.

Input Schema

TableJSON Schema

Name	Required	Description
`target_id`	Yes	Chrome target ID from interceptor_chrome_launch
`delta_y`	Yes	Vertical scroll delta in pixels (positive = scroll down)
`delta_x`	No	Horizontal scroll delta in pixels (default: 0)
`duration_ms`	No	Total scroll duration in ms (default: 400)

Implementation Reference

src/humanizer/engine.ts:419-452 (handler)

The 'scroll' method in HumanizerEngine calculates scroll steps and dispatches mouseWheel events to the target session.

async scroll(
  targetId: string,
  deltaY: number,
  deltaX?: number,
  durationMs?: number,
): Promise<{ totalMs: number; eventsDispatched: number }> {
  const state = await this.getSession(targetId);
  const scrollSteps = calculateScrollSteps({
    deltaY,
    deltaX,
    durationMs: durationMs ?? 400,
  });

  let totalMs = 0;
  let eventsDispatched = 0;

  for (const step of scrollSteps) {
    await sleep(step.delayMs);
    totalMs += step.delayMs;

    await state.session.send("Input.dispatchMouseEvent", {
      type: "mouseWheel",
      x: state.mouseX,
      y: state.mouseY,
      deltaX: step.deltaX,
      deltaY: step.deltaY,
      button: "none",
      buttons: 0,
    });
    eventsDispatched++;
  }

  return { totalMs, eventsDispatched };
}

src/tools/humanizer.ts:171-200 (registration)

The 'humanizer_scroll' tool is registered in the server, accepting input parameters like delta_y and duration_ms, and calls the HumanizerEngine.scroll method.

server.tool(
  "humanizer_scroll",
  "Scroll with natural acceleration/deceleration using easeInOutQuad velocity distribution. " +
  "Dispatches multiple wheel events to simulate human scroll behavior.",
  {
    target_id: z.string().describe("Chrome target ID from interceptor_chrome_launch"),
    delta_y: z.number().describe("Vertical scroll delta in pixels (positive = scroll down)"),
    delta_x: z.number().optional().default(0)
      .describe("Horizontal scroll delta in pixels (default: 0)"),
    duration_ms: z.number().optional().default(400)
      .describe("Total scroll duration in ms (default: 400)"),
  },
  async ({ target_id, delta_y, delta_x, duration_ms }) => {
    try {
      const result = await humanizerEngine.scroll(target_id, delta_y, delta_x, duration_ms);
      return {
        content: [{
          type: "text",
          text: JSON.stringify({
            status: "success",
            target_id,
            action: "scroll",
            delta: { x: delta_x, y: delta_y },
            stats: {
              total_ms: result.totalMs,
              events_dispatched: result.eventsDispatched,
            },
          }),
        }],
      };

proxy-mcp