diff --git a/canvas/src/components/tabs/chat/__tests__/AttachmentViews.test.tsx b/canvas/src/components/tabs/chat/__tests__/AttachmentViews.test.tsx
new file mode 100644
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+++ b/canvas/src/components/tabs/chat/__tests__/AttachmentViews.test.tsx
@@ -0,0 +1,167 @@
+// @vitest-environment jsdom
+/**
+ * Tests for AttachmentViews.tsx — PendingAttachmentPill + AttachmentChip.
+ *
+ * 16 cases covering:
+ * - PendingAttachmentPill: name, size, aria-label, onRemove, one-button guard
+ * - AttachmentChip: name+glyph, size, no-size, title, onDownload, tone=user/agent, one-button guard
+ *
+ * Pattern: render the real component, inspect actual DOM output.
+ * No mocking of the components themselves.
+ */
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+import { render, screen, fireEvent, cleanup } from "@testing-library/react";
+import React from "react";
+
+import {
+  PendingAttachmentPill,
+  AttachmentChip,
+} from "../AttachmentViews";
+import type { ChatAttachment } from "../types";
+
+afterEach(cleanup);
+
+// ─── Shared test fixtures ────────────────────────────────────────────────────
+
+const makeFile = (name: string, size: number): File =>
+  new File([new Uint8Array(size)], name, { type: "application/octet-stream" });
+
+const makeAttachment = (overrides: Partial<ChatAttachment> = {}): ChatAttachment => ({
+  name: "report.pdf",
+  uri: "workspace:/workspace/report.pdf",
+  mimeType: "application/pdf",
+  size: 42_000,
+  ...overrides,
+});
+
+// ─── PendingAttachmentPill ───────────────────────────────────────────────────
+
+describe("PendingAttachmentPill", () => {
+  describe("renders", () => {
+    it("displays the file name", () => {
+      const file = makeFile("notes.txt", 128);
+      render(<PendingAttachmentPill file={file} onRemove={vi.fn()} />);
+      expect(screen.getByText("notes.txt")).toBeTruthy();
+    });
+
+    it("displays formatted size in bytes", () => {
+      // File([], name) gives size 0; pass a Uint8Array to set actual byte size.
+      const file = new File([new Uint8Array(512)], "tiny.bin");
+      render(<PendingAttachmentPill file={file} onRemove={vi.fn()} />);
+      expect(screen.getByText("512 B")).toBeTruthy();
+    });
+
+    it("displays formatted size in KB", () => {
+      const file = new File([new Uint8Array(5 * 1024)], "medium.zip");
+      render(<PendingAttachmentPill file={file} onRemove={vi.fn()} />);
+      expect(screen.getByText("5 KB")).toBeTruthy();
+    });
+
+    it("displays formatted size in MB", () => {
+      const file = new File([new Uint8Array(Math.floor(1.5 * 1024 * 1024))], "large.tar");
+      render(<PendingAttachmentPill file={file} onRemove={vi.fn()} />);
+      // formatSize uses toFixed(1) for MB → "1.5 MB"
+      expect(screen.getByText("1.5 MB")).toBeTruthy();
+    });
+
+    it('× button has aria-label "Remove <filename>"', () => {
+      const file = makeFile("memo.pdf", 1_000);
+      render(<PendingAttachmentPill file={file} onRemove={vi.fn()} />);
+      expect(screen.getByRole("button", { name: /remove memo\.pdf/i })).toBeTruthy();
+    });
+
+    it("calls onRemove when × button is clicked", () => {
+      const onRemove = vi.fn();
+      const file = makeFile("photo.png", 999);
+      render(<PendingAttachmentPill file={file} onRemove={onRemove} />);
+      fireEvent.click(screen.getByRole("button", { name: /remove photo\.png/i }));
+      expect(onRemove).toHaveBeenCalledTimes(1);
+    });
+
+    it("renders exactly one button (no stray click targets)", () => {
+      const file = makeFile("doc.docx", 20_000);
+      render(<PendingAttachmentPill file={file} onRemove={vi.fn()} />);
+      const buttons = screen.getAllByRole("button");
+      expect(buttons).toHaveLength(1);
+    });
+  });
+});
+
+// ─── AttachmentChip ────────────────────────────────────────────────────────
+
+describe("AttachmentChip", () => {
+  let onDownload: ReturnType<typeof vi.fn>;
+
+  beforeEach(() => {
+    onDownload = vi.fn();
+  });
+
+  describe("renders", () => {
+    it("displays the attachment name", () => {
+      const att = makeAttachment({ name: "analysis.csv" });
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      expect(screen.getByText("analysis.csv")).toBeTruthy();
+    });
+
+    it("displays the download glyph (SVG icon) inside the button", () => {
+      const att = makeAttachment();
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      const button = screen.getByRole("button");
+      // DownloadGlyph is an <svg aria-hidden="true"> inside the button
+      const svg = button.querySelector("svg");
+      expect(svg).not.toBeNull();
+    });
+
+    it("displays size when provided", () => {
+      const att = makeAttachment({ size: 41_000 }); // ~40 KB
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      // 41 000 / 1024 ≈ 40 → "40 KB"
+      expect(screen.getByText("40 KB")).toBeTruthy();
+    });
+
+    it("omits size span when size is undefined", () => {
+      const att = makeAttachment({ size: undefined });
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      // "KB" should not appear; only the name + download glyph are visible
+      expect(screen.queryByText(/KB/i)).toBeNull();
+    });
+
+    it('has title attribute for hover tooltip', () => {
+      const att = makeAttachment({ name: "readme.md" });
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      const button = screen.getByRole("button");
+      expect(button.getAttribute("title")).toBe("Download readme.md");
+    });
+
+    it("calls onDownload with the attachment when clicked", () => {
+      const att = makeAttachment({ name: "data.json" });
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      fireEvent.click(screen.getByRole("button"));
+      expect(onDownload).toHaveBeenCalledTimes(1);
+      expect(onDownload).toHaveBeenCalledWith(att);
+    });
+
+    it("tone=user applies blue-400 accent class", () => {
+      const att = makeAttachment();
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="user" />);
+      const button = screen.getByRole("button");
+      // The user tone includes blue-400/blue-100 accent classes.
+      // We check the rendered class string includes the accent class.
+      expect(button.className).toMatch(/blue-400/);
+    });
+
+    it("tone=agent omits blue-400 accent class", () => {
+      const att = makeAttachment();
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="agent" />);
+      const button = screen.getByRole("button");
+      expect(button.className).not.toMatch(/blue-400/);
+    });
+
+    it("renders exactly one button (no duplicate download targets)", () => {
+      const att = makeAttachment({ name: "budget.xlsx", size: 80_000 });
+      render(<AttachmentChip attachment={att} onDownload={onDownload} tone="user" />);
+      const buttons = screen.getAllByRole("button");
+      expect(buttons).toHaveLength(1);
+    });
+  });
+});