diff --git a/cmd/generate_changelog/incoming/1904.txt b/cmd/generate_changelog/incoming/1904.txt
new file mode 100644
index 00000000..9bdbadc5
--- /dev/null
+++ b/cmd/generate_changelog/incoming/1904.txt
@@ -0,0 +1,7 @@
+### PR [#1904](https://github.com/danielmiessler/Fabric/pull/1904) by [majiayu000](https://github.com/majiayu000): fix: resolve WebUI tooltips not rendering due to overflow clipping
+
+- Fix: resolve WebUI tooltips not rendering due to overflow clipping by using position: fixed and getBoundingClientRect() to calculate tooltip position dynamically, preventing tooltips from being clipped by parent containers with overflow: hidden
+- Refactor: extract tooltip positioning logic into separate positioning.ts module for better code organization and maintainability
+- Improve accessibility with aria-describedby attributes and unique IDs for better screen reader support
+- Add reactive tooltip position updates on scroll and resize events for dynamic positioning
+- Add SSR safety with isBrowser flag check and comprehensive unit test coverage for the positioning functions
diff --git a/web/src/lib/components/ui/tooltip/Tooltip.svelte b/web/src/lib/components/ui/tooltip/Tooltip.svelte
index 59567e1d..7420bc6e 100644
--- a/web/src/lib/components/ui/tooltip/Tooltip.svelte
+++ b/web/src/lib/components/ui/tooltip/Tooltip.svelte
@@ -1,43 +1,86 @@
 <script lang="ts">
+  import { onMount } from 'svelte';
+  import { calculateTooltipPosition, formatPositionStyle, type TooltipPosition } from './positioning';
+
   export let text: string;
-  export let position: 'top' | 'bottom' | 'left' | 'right' = 'top';
+  // biome-ignore lint/style/useConst: Svelte props must use 'let' even when not reassigned
+  export let position: TooltipPosition = 'top';
 
   let tooltipVisible = false;
-  let tooltipElement: HTMLDivElement;
+  // eslint-disable-next-line no-unassigned-vars -- Assigned via bind:this in template
+  let triggerElement: HTMLDivElement;
+  let isBrowser = false;
+  // biome-ignore lint/correctness/noUnusedVariables: Used in template for aria-describedby and id
+  const tooltipId = `tooltip-${Math.random().toString(36).substring(2, 9)}`;
 
+  // Reactive tooltip positioning - recalculates when position or element changes
+  $: tooltipStyle = triggerElement && tooltipVisible
+    ? formatPositionStyle(calculateTooltipPosition(triggerElement.getBoundingClientRect(), position))
+    : '';
+
+  function updatePosition() {
+    if (triggerElement && tooltipVisible) {
+      tooltipStyle = formatPositionStyle(calculateTooltipPosition(triggerElement.getBoundingClientRect(), position));
+    }
+  }
+
+  // biome-ignore lint/correctness/noUnusedVariables: Used in template event handlers
   function showTooltip() {
     tooltipVisible = true;
   }
 
+  // biome-ignore lint/correctness/noUnusedVariables: Used in template event handlers
   function hideTooltip() {
     tooltipVisible = false;
   }
+
+  // Handle window scroll and resize to keep tooltip positioned correctly
+  // Only runs in browser (not during SSR)
+  onMount(() => {
+    isBrowser = true;
+    return () => {
+      if (isBrowser) {
+        window.removeEventListener('scroll', updatePosition, true);
+        window.removeEventListener('resize', updatePosition);
+      }
+    };
+  });
+
+  // Add/remove event listeners reactively when tooltip visibility changes
+  $: if (isBrowser && tooltipVisible) {
+    window.addEventListener('scroll', updatePosition, true);
+    window.addEventListener('resize', updatePosition);
+  } else if (isBrowser && !tooltipVisible) {
+    window.removeEventListener('scroll', updatePosition, true);
+    window.removeEventListener('resize', updatePosition);
+  }
 </script>
 
-<!-- svelte-ignore a11y-no-noninteractive-element-interactions a11y-mouse-events-have-key-events -->
 <div class="tooltip-container">
-  <div 
+  <div
+    bind:this={triggerElement}
     class="tooltip-trigger"
     on:mouseenter={showTooltip}
     on:mouseleave={hideTooltip}
     on:focusin={showTooltip}
     on:focusout={hideTooltip}
-    role="tooltip"
-    aria-label="Tooltip trigger"
+    aria-describedby={tooltipVisible ? tooltipId : undefined}
+    role="button"
+    tabindex="0"
   >
     <slot />
   </div>
-  
+
   {#if tooltipVisible}
     <div
-      bind:this={tooltipElement}
-      class="tooltip absolute z-[9999] px-2 py-1 text-xs rounded bg-gray-900/90 text-white whitespace-nowrap shadow-lg backdrop-blur-sm"
+      id={tooltipId}
+      class="tooltip fixed z-[9999] px-2 py-1 text-xs rounded bg-gray-900/90 text-white whitespace-nowrap shadow-lg backdrop-blur-sm"
       class:top="{position === 'top'}"
       class:bottom="{position === 'bottom'}"
       class:left="{position === 'left'}"
       class:right="{position === 'right'}"
+      style={tooltipStyle}
       role="tooltip"
-      aria-label={text}
     >
       {text}
       <div class="tooltip-arrow" role="presentation" />
@@ -57,32 +100,24 @@
 
   .tooltip {
     pointer-events: none;
-    transition: all 150ms ease-in-out;
+    transition: opacity 150ms ease-in-out;
     opacity: 1;
   }
 
   .tooltip.top {
-    bottom: calc(100% + 5px);
-    left: 50%;
-    transform: translateX(-50%);
+    transform: translate(-50%, -100%);
   }
 
   .tooltip.bottom {
-    top: calc(100% + 5px);
-    left: 50%;
-    transform: translateX(-50%);
+    transform: translate(-50%, 0);
   }
 
   .tooltip.left {
-    right: calc(100% + 5px);
-    top: 50%;
-    transform: translateY(-50%);
+    transform: translate(-100%, -50%);
   }
 
   .tooltip.right {
-    left: calc(100% + 5px);
-    top: 50%;
-    transform: translateY(-50%);
+    transform: translate(0, -50%);
   }
 
   .tooltip-arrow {
diff --git a/web/src/lib/components/ui/tooltip/Tooltip.test.ts b/web/src/lib/components/ui/tooltip/Tooltip.test.ts
new file mode 100644
index 00000000..e8ad6db2
--- /dev/null
+++ b/web/src/lib/components/ui/tooltip/Tooltip.test.ts
@@ -0,0 +1,56 @@
+import { describe, expect, it } from 'vitest';
+import { calculateTooltipPosition, formatPositionStyle, TOOLTIP_GAP } from './positioning';
+
+describe('Tooltip positioning logic', () => {
+  const mockRect = {
+    top: 100,
+    bottom: 130,
+    left: 200,
+    right: 300,
+    width: 100,
+    height: 30,
+    x: 200,
+    y: 100,
+    toJSON: () => ({})
+  } as DOMRect;
+
+  it('calculates top position correctly', () => {
+    const result = calculateTooltipPosition(mockRect, 'top');
+    expect(result.top).toBe(92); // 100 - 8
+    expect(result.left).toBe(250); // 200 + 100/2
+  });
+
+  it('calculates bottom position correctly', () => {
+    const result = calculateTooltipPosition(mockRect, 'bottom');
+    expect(result.top).toBe(138); // 130 + 8
+    expect(result.left).toBe(250); // 200 + 100/2
+  });
+
+  it('calculates left position correctly', () => {
+    const result = calculateTooltipPosition(mockRect, 'left');
+    expect(result.top).toBe(115); // 100 + 30/2
+    expect(result.left).toBe(192); // 200 - 8
+  });
+
+  it('calculates right position correctly', () => {
+    const result = calculateTooltipPosition(mockRect, 'right');
+    expect(result.top).toBe(115); // 100 + 30/2
+    expect(result.left).toBe(308); // 300 + 8
+  });
+
+  it('uses the correct gap value', () => {
+    expect(TOOLTIP_GAP).toBe(8);
+  });
+
+  it('formats position style correctly', () => {
+    const position = { top: 100, left: 200 };
+    const style = formatPositionStyle(position);
+    expect(style).toBe('top: 100px; left: 200px;');
+  });
+
+  it('respects custom gap parameter', () => {
+    const customGap = 16;
+    const result = calculateTooltipPosition(mockRect, 'top', customGap);
+    expect(result.top).toBe(84); // 100 - 16
+  });
+});
diff --git a/web/src/lib/components/ui/tooltip/positioning.ts b/web/src/lib/components/ui/tooltip/positioning.ts
new file mode 100644
index 00000000..e52c4d2f
--- /dev/null
+++ b/web/src/lib/components/ui/tooltip/positioning.ts
@@ -0,0 +1,27 @@
+export const TOOLTIP_GAP = 8;
+
+export type TooltipPosition = 'top' | 'bottom' | 'left' | 'right';
+
+export interface Position {
+  top: number;
+  left: number;
+}
+
+export function calculateTooltipPosition(
+  rect: DOMRect,
+  position: TooltipPosition,
+  gap: number = TOOLTIP_GAP
+): Position {
+  const positions: Record<TooltipPosition, Position> = {
+    top: { top: rect.top - gap, left: rect.left + rect.width / 2 },
+    bottom: { top: rect.bottom + gap, left: rect.left + rect.width / 2 },
+    left: { top: rect.top + rect.height / 2, left: rect.left - gap },
+    right: { top: rect.top + rect.height / 2, left: rect.right + gap }
+  };
+
+  return positions[position];
+}
+
+export function formatPositionStyle(position: Position): string {
+  return `top: ${position.top}px; left: ${position.left}px;`;
+}