diff --git a/apps/web/src/board/filters.test.ts b/apps/web/src/board/filters.test.ts
new file mode 100644
index 0000000..73882b3
--- /dev/null
+++ b/apps/web/src/board/filters.test.ts
@@ -0,0 +1,76 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { me, type StoreTask } from "../store/index.js";
+import { assigneeFilter, cardFilter, clearFilters, mineOnly, search } from "./filters.js";
+
+function task(patch: Partial<StoreTask> = {}): StoreTask {
+  return {
+    id: "tk_1",
+    listId: "ls_1",
+    title: "Review proposal",
+    statusId: "st_open",
+    assigneeId: null,
+    assignedBy: null,
+    assignedAt: null,
+    priority: null,
+    dueDate: null,
+    snoozedUntil: null,
+    blockedNote: null,
+    tags: [],
+    position: 0,
+    createdAt: 0,
+    updatedAt: 0,
+    handoff: null,
+    ...patch,
+  };
+}
+
+function reset(): void {
+  clearFilters();
+  me.value = null;
+}
+
+beforeEach(reset);
+afterEach(reset);
+
+describe("cardFilter", () => {
+  it("matches a title substring with a trimmed, case-insensitive query", () => {
+    search.value = "  PROPOS  ";
+    expect(cardFilter.value(task())).toBe(true);
+    expect(cardFilter.value(task({ title: "Send invoice" }))).toBe(false);
+  });
+
+  it("matches a visible tag substring case-insensitively", () => {
+    search.value = "  VOIC  ";
+    expect(cardFilter.value(task({ tags: ["Finance", "Invoice"] }))).toBe(true);
+    expect(cardFilter.value(task({ tags: ["Finance"] }))).toBe(false);
+  });
+
+  it("does not match machine-only ext: tags", () => {
+    search.value = "invoice";
+    expect(cardFilter.value(task({ tags: ["ext:invoice", "Finance"] }))).toBe(false);
+    expect(cardFilter.value(task({ tags: ["ext:invoice", "Invoice"] }))).toBe(true);
+  });
+
+  it("requires both a search match and the selected assignee", () => {
+    search.value = "invoice";
+    assigneeFilter.value = "us_1";
+    expect(cardFilter.value(task({ title: "Send invoice", assigneeId: "us_1" }))).toBe(true);
+    expect(cardFilter.value(task({ tags: ["Invoice"], assigneeId: "us_1" }))).toBe(true);
+    expect(cardFilter.value(task({ tags: ["Invoice"], assigneeId: "us_2" }))).toBe(false);
+    expect(cardFilter.value(task({ tags: ["Invoice"] }))).toBe(false);
+    expect(cardFilter.value(task({ assigneeId: "us_1" }))).toBe(false);
+  });
+
+  it("combines search with mine only, taking precedence over the assignee filter", () => {
+    me.value = {
+      id: "us_me", email: "me@example.com", name: "Me",
+      role: "member", deactivated: false, createdAt: 0,
+    };
+    mineOnly.value = true;
+    assigneeFilter.value = "us_other";
+    search.value = "invoice";
+    expect(cardFilter.value(task({ tags: ["Invoice"], assigneeId: "us_me" }))).toBe(true);
+    expect(cardFilter.value(task({ tags: ["Invoice"], assigneeId: "us_other" }))).toBe(false);
+    expect(cardFilter.value(task({ assigneeId: "us_me" }))).toBe(false);
+  });
+});
diff --git a/apps/web/src/board/filters.ts b/apps/web/src/board/filters.ts
index 4fc862b..ecce17b 100644
--- a/apps/web/src/board/filters.ts
+++ b/apps/web/src/board/filters.ts
@@ -1,7 +1,7 @@
 // Board filter state. Client-side only — it narrows the tasks already loaded.
 // Full-text search across the workspace goes through /api/tasks/search later.
 import { computed, signal, type ReadonlySignal } from "@preact/signals";
-import { isSnoozed } from "../lib/fmt.js";
+import { isSnoozed, visibleTags } from "../lib/fmt.js";
 import { me, type StoreTask } from "../store/index.js";
 
 /** Empty = every status shows. */
@@ -52,7 +52,11 @@ export const cardFilter: ReadonlySignal<(task: StoreTask) => boolean> = computed
   if (!q && !assignee) return () => true;
   return (task: StoreTask) => {
     if (assignee && task.assigneeId !== assignee) return false;
-    if (q && !task.title.toLowerCase().includes(q)) return false;
+    if (
+      q &&
+      !task.title.toLowerCase().includes(q) &&
+      !visibleTags(task.tags).some((tag) => tag.toLowerCase().includes(q))
+    ) return false;
     return true;
   };
 });