diff --git a/packages/tool-server/src/utils/debugger/scripts/component-tree.ts b/packages/tool-server/src/utils/debugger/scripts/component-tree.ts
index aef7f7fe..818bebf5 100644
--- a/packages/tool-server/src/utils/debugger/scripts/component-tree.ts
+++ b/packages/tool-server/src/utils/debugger/scripts/component-tree.ts
@@ -122,14 +122,35 @@ export function makeComponentTreeScript(opts: {
     return t.displayName || t.name || null;
   }
 
+  // Per-host dedup/measure cache key. MUST be a primitive: on Fabric the host
+  // "node" is a shadow-node OBJECT, so the old key ('f' + hi.n) stringified it
+  // to "f[object Object]" for EVERY node — collapsing all hosts to one entry and
+  // giving every component the first (root) view's full-screen rect, i.e. a
+  // (0.5, 0.5) tap for everything. Key by the numeric nativeTag instead, with a
+  // WeakMap-by-identity fallback so distinct nodes never share a key.
+  var _hostKeySeq = 0;
+  var _fabricKeyMap = typeof WeakMap !== 'undefined' ? new WeakMap() : null;
+
   function getHostInfo(fiber) {
     if (typeof fiber.type !== 'string' || !fiber.stateNode) return null;
-    if (useFabric && fiber.stateNode.node) return { f: true, n: fiber.stateNode.node };
+    if (useFabric && fiber.stateNode.node) {
+      var sn = fiber.stateNode;
+      var fKey;
+      if (sn.canonical && typeof sn.canonical.nativeTag === 'number') {
+        fKey = 'f' + sn.canonical.nativeTag;
+      } else if (_fabricKeyMap) {
+        fKey = _fabricKeyMap.get(sn.node);
+        if (fKey === undefined) { fKey = 'fo' + (++_hostKeySeq); _fabricKeyMap.set(sn.node, fKey); }
+      } else {
+        fKey = 'fo' + (++_hostKeySeq);
+      }
+      return { f: true, n: sn.node, key: fKey };
+    }
     if (!useFabric) {
       if (fiber.stateNode.canonical && typeof fiber.stateNode.canonical.nativeTag === 'number')
-        return { f: false, n: fiber.stateNode.canonical.nativeTag };
+        return { f: false, n: fiber.stateNode.canonical.nativeTag, key: 'p' + fiber.stateNode.canonical.nativeTag };
       if (typeof fiber.stateNode._nativeTag === 'number')
-        return { f: false, n: fiber.stateNode._nativeTag };
+        return { f: false, n: fiber.stateNode._nativeTag, key: 'p' + fiber.stateNode._nativeTag };
     }
     return null;
   }
@@ -249,7 +270,7 @@ export function makeComponentTreeScript(opts: {
   for (var ci = 0; ci < candidates.length; ci++) {
     var hi = candidates[ci].hostInfo;
     if (!hi) continue;
-    var key = (hi.f ? 'f' : 'p') + hi.n;
+    var key = hi.key;
     if (!(key in hostKeyMap)) {
       hostKeyMap[key] = uniqueHosts.length;
       uniqueHosts.push(hi);
@@ -277,7 +298,7 @@ export function makeComponentTreeScript(opts: {
   var rects = await Promise.all(uniqueHosts.map(measureOne));
 
   for (var ri = 0; ri < uniqueHosts.length; ri++) {
-    var rKey = (uniqueHosts[ri].f ? 'f' : 'p') + uniqueHosts[ri].n;
+    var rKey = uniqueHosts[ri].key;
     rectCache[rKey] = rects[ri];
   }
 
@@ -285,7 +306,7 @@ export function makeComponentTreeScript(opts: {
   for (var ai = 0; ai < candidates.length; ai++) {
     var h = candidates[ai].hostInfo;
     if (h) {
-      var rk = (h.f ? 'f' : 'p') + h.n;
+      var rk = h.key;
       candidates[ai].rect = rectCache[rk] || null;
     }
   }
diff --git a/packages/tool-server/test/debugger/component-tree-script.test.ts b/packages/tool-server/test/debugger/component-tree-script.test.ts
new file mode 100644
index 00000000..5fc652b0
--- /dev/null
+++ b/packages/tool-server/test/debugger/component-tree-script.test.ts
@@ -0,0 +1,122 @@
+import { describe, it, expect } from "vitest";
+import { makeComponentTreeScript } from "../../src/utils/debugger/scripts/component-tree";
+
+/**
+ * Reproduces the Fabric tap-coordinate collapse bug at the injected-script
+ * level (the existing component-tree.test.ts only tests the pure post-processor
+ * with pre-filled rects, so it never exercised this path).
+ *
+ * Builds a minimal Fabric fiber tree of three sibling app components, each
+ * wrapping a host RCTView whose shadow node is a DISTINCT object with a DISTINCT
+ * nativeTag, measured at a DISTINCT on-screen position. The bug keyed the
+ * per-host measure cache by the shadow-node OBJECT ("f" + node → "f[object
+ * Object]" for every node), collapsing all hosts to one entry so every
+ * component inherited the first host's rect — i.e. a (0.5, 0.5) tap for all.
+ */
+
+interface Rect {
+  x: number;
+  y: number;
+  w: number;
+  h: number;
+  px: number;
+  py: number;
+}
+
+function buildFabricTree() {
+  const rectByNode = new Map<object, Rect>();
+  let nextTag = 100;
+
+  function hostFiber(rect: Rect) {
+    const node = {}; // a distinct Fabric shadow-node object per host
+    rectByNode.set(node, rect);
+    return {
+      type: "RCTView",
+      stateNode: { node, canonical: { nativeTag: ++nextTag } },
+      memoizedProps: {},
+      child: null,
+      sibling: null,
+    } as Record<string, unknown>;
+  }
+
+  function compFiber(name: string, rect: Rect, sibling: unknown) {
+    const type = function () {} as { displayName?: string };
+    type.displayName = name;
+    return {
+      type,
+      stateNode: null,
+      memoizedProps: { children: name },
+      child: hostFiber(rect),
+      sibling,
+    } as Record<string, unknown>;
+  }
+
+  // Distinct vertical positions (px/py are what the script records).
+  const compC = compFiber("CompC", { x: 0, y: 0, w: 200, h: 50, px: 10, py: 600 }, null);
+  const compB = compFiber("CompB", { x: 0, y: 0, w: 200, h: 50, px: 10, py: 300 }, compC);
+  const compA = compFiber("CompA", { x: 0, y: 0, w: 200, h: 50, px: 10, py: 100 }, compB);
+
+  return { root: { current: { child: compA } }, rectByNode };
+}
+
+async function runInjectedScript() {
+  const { root, rectByNode } = buildFabricTree();
+  const script = makeComponentTreeScript({ requestId: "test", includeSkipped: false });
+
+  let captured: { result: string } | undefined;
+  const sandbox = {
+    window: {
+      __REACT_DEVTOOLS_GLOBAL_HOOK__: { getFiberRoots: () => new Set([root]) },
+    },
+    nativeFabricUIManager: {
+      measure(
+        node: object,
+        cb: (x: number, y: number, w: number, h: number, px: number, py: number) => void
+      ) {
+        const r = rectByNode.get(node)!;
+        cb(r.x, r.y, r.w, r.h, r.px, r.py);
+      },
+    },
+    __r: Object.assign((_id: number) => ({ Dimensions: { get: () => ({ width: 400, height: 800 }) } }), {
+      getModules: () => [[0, { isInitialized: true }]],
+    }),
+    __argent_callback: (json: string) => {
+      captured = JSON.parse(json);
+    },
+  };
+
+  const runner = new Function(
+    "window",
+    "nativeFabricUIManager",
+    "__r",
+    "__argent_callback",
+    `return ${script}`
+  );
+  await runner(sandbox.window, sandbox.nativeFabricUIManager, sandbox.__r, sandbox.__argent_callback);
+
+  if (!captured) throw new Error("script did not invoke __argent_callback");
+  return JSON.parse(captured.result) as {
+    screenW: number;
+    screenH: number;
+    components: Array<{ name: string; rect: { x: number; y: number; w: number; h: number } | null }>;
+  };
+}
+
+describe("makeComponentTreeScript — Fabric measurement", () => {
+  it("gives each host its own measured rect instead of collapsing onto one", async () => {
+    const result = await runInjectedScript();
+
+    expect(result.screenW).toBe(400);
+    expect(result.screenH).toBe(800);
+
+    const comps = Object.fromEntries(result.components.map((c) => [c.name, c.rect]));
+    expect(comps.CompA).toMatchObject({ y: 100 });
+    expect(comps.CompB).toMatchObject({ y: 300 });
+    expect(comps.CompC).toMatchObject({ y: 600 });
+
+    // The regression: all three rects were identical (collapsed onto the first
+    // host), which renders as the same centre-of-screen tap for every element.
+    const distinctY = new Set(result.components.map((c) => c.rect?.y));
+    expect(distinctY.size).toBe(3);
+  });
+});