diff --git a/packages/ui/src/stores/useFileSearchStore.test.ts b/packages/ui/src/stores/useFileSearchStore.test.ts
index 59fa60c1..ad59eaa8 100644
--- a/packages/ui/src/stores/useFileSearchStore.test.ts
+++ b/packages/ui/src/stores/useFileSearchStore.test.ts
@@ -89,4 +89,16 @@ describe('useFileSearchStore', () => {
     expect(cacheEntries).toHaveLength(1);
     expect(cacheEntries[0]?.files).toEqual([{ path: 'fresh.ts' }]);
   });
+
+  test('keeps directory and query separators from colliding in cache keys', async () => {
+    const firstPromise = useFileSearchStore.getState().searchFiles('/project::nested', 'foo');
+    searchRequests[0].resolve([{ path: 'first.ts' }]);
+    await firstPromise;
+
+    const secondPromise = useFileSearchStore.getState().searchFiles('/project', 'nested::foo');
+    expect(searchRequests).toHaveLength(2);
+
+    searchRequests[1].resolve([{ path: 'second.ts' }]);
+    expect(await secondPromise).toEqual([{ path: 'second.ts' }]);
+  });
 });
diff --git a/packages/ui/src/stores/useFileSearchStore.ts b/packages/ui/src/stores/useFileSearchStore.ts
index 65b01736..31e969b5 100644
--- a/packages/ui/src/stores/useFileSearchStore.ts
+++ b/packages/ui/src/stores/useFileSearchStore.ts
@@ -34,7 +34,16 @@ const buildCacheKey = (
 ) => {
   const normalizedDirectory = directory.trim();
   const normalizedQuery = query.trim().toLowerCase();
-  return `${normalizedDirectory}::${normalizedQuery}::${limit}::${includeHidden ? '1' : '0'}::${respectGitignore ? '1' : '0'}::${type}`;
+  return JSON.stringify([normalizedDirectory, normalizedQuery, limit, includeHidden, respectGitignore, type]);
+};
+
+const cacheKeyMatchesDirectory = (cacheKey: string, directory: string) => {
+  try {
+    const value: unknown = JSON.parse(cacheKey);
+    return Array.isArray(value) && value[0] === directory;
+  } catch {
+    return false;
+  }
 };
 
 export const useFileSearchStore = create<FileSearchStoreState>()(
@@ -127,12 +136,11 @@ export const useFileSearchStore = create<FileSearchStoreState>()(
         }
 
         const normalizedDirectory = directory.trim();
-        const prefix = `${normalizedDirectory}::`;
 
         set((state) => {
           const nextCache = { ...state.cache };
           const nextKeys = state.cacheKeys.filter((cacheKey) => {
-            if (cacheKey.startsWith(prefix)) {
+            if (cacheKeyMatchesDirectory(cacheKey, normalizedDirectory)) {
               delete nextCache[cacheKey];
               return false;
             }
@@ -140,7 +148,7 @@ export const useFileSearchStore = create<FileSearchStoreState>()(
           });
 
           const nextInFlightEntries = Object.entries(state.inFlight).filter(
-            ([key]) => !key.startsWith(prefix)
+            ([key]) => !cacheKeyMatchesDirectory(key, normalizedDirectory)
           );
           const nextInFlight = Object.fromEntries(nextInFlightEntries);