diff --git a/canvas/src/components/tabs/chat/AttachmentAudio.tsx b/canvas/src/components/tabs/chat/AttachmentAudio.tsx
new file mode 100644
index 00000000..b696125d
--- /dev/null
+++ b/canvas/src/components/tabs/chat/AttachmentAudio.tsx
@@ -0,0 +1,124 @@
+"use client";
+
+// AttachmentAudio — inline native HTML5 <audio controls> player for
+// chat attachments (RFC #2991, PR-2).
+//
+// Same auth + Blob-URL pattern as AttachmentImage / AttachmentVideo.
+// Native audio control bar handles play/pause/scrub/volume/download,
+// and there's no fullscreen UI to worry about (audio doesn't need
+// AttachmentLightbox).
+
+import { useState, useEffect, useRef } from "react";
+import type { ChatAttachment } from "./types";
+import { isPlatformAttachment, resolveAttachmentHref } from "./uploads";
+import { AttachmentChip } from "./AttachmentViews";
+
+interface Props {
+  workspaceId: string;
+  attachment: ChatAttachment;
+  onDownload: (a: ChatAttachment) => void;
+  tone: "user" | "agent";
+}
+
+type FetchState =
+  | { kind: "idle" }
+  | { kind: "loading" }
+  | { kind: "ready"; src: string }
+  | { kind: "error" };
+
+export function AttachmentAudio({ workspaceId, attachment, onDownload, tone }: Props) {
+  const [state, setState] = useState<FetchState>({ kind: "idle" });
+  const blobUrlRef = useRef<string | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    setState({ kind: "loading" });
+
+    if (!isPlatformAttachment(attachment.uri)) {
+      const href = resolveAttachmentHref(workspaceId, attachment.uri);
+      if (!cancelled) setState({ kind: "ready", src: href });
+      return;
+    }
+
+    void (async () => {
+      try {
+        const href = resolveAttachmentHref(workspaceId, attachment.uri);
+        const headers: Record<string, string> = {};
+        const adminToken = process.env.NEXT_PUBLIC_ADMIN_TOKEN;
+        if (adminToken) headers["Authorization"] = `Bearer ${adminToken}`;
+        const slug = getTenantSlug();
+        if (slug) headers["X-Molecule-Org-Slug"] = slug;
+        const res = await fetch(href, {
+          headers,
+          credentials: "include",
+          signal: AbortSignal.timeout(60_000),
+        });
+        if (!res.ok) {
+          if (!cancelled) setState({ kind: "error" });
+          return;
+        }
+        const blob = await res.blob();
+        const url = URL.createObjectURL(blob);
+        blobUrlRef.current = url;
+        if (cancelled) {
+          URL.revokeObjectURL(url);
+          return;
+        }
+        setState({ kind: "ready", src: url });
+      } catch {
+        if (!cancelled) setState({ kind: "error" });
+      }
+    })();
+
+    return () => {
+      cancelled = true;
+      if (blobUrlRef.current) {
+        URL.revokeObjectURL(blobUrlRef.current);
+        blobUrlRef.current = null;
+      }
+    };
+  }, [workspaceId, attachment.uri]);
+
+  if (state.kind === "error") {
+    return <AttachmentChip attachment={attachment} onDownload={onDownload} tone={tone} />;
+  }
+  if (state.kind === "idle" || state.kind === "loading") {
+    return (
+      <div
+        className="rounded-md border border-line/50 bg-surface-card/40 animate-pulse"
+        style={{ width: 280, height: 40 }}
+        aria-label={`Loading ${attachment.name}`}
+      />
+    );
+  }
+
+  return (
+    <div
+      className={`inline-flex flex-col gap-1 rounded-md border px-2 py-1 ${
+        tone === "user" ? "border-blue-400/30 bg-accent-strong/10" : "border-line/50 bg-surface-card/40"
+      }`}
+    >
+      {/* Filename label so the user knows what they're hearing
+          before pressing play. Short, single-line, truncated. */}
+      <span className="text-[10px] text-ink-mid truncate max-w-[280px]" title={attachment.name}>
+        {attachment.name}
+      </span>
+      <audio
+        controls
+        preload="metadata"
+        src={state.src}
+        style={{ width: 280, height: 32 }}
+        onError={() => setState({ kind: "error" })}
+      >
+        {attachment.name}
+      </audio>
+    </div>
+  );
+}
+
+function getTenantSlug(): string | null {
+  if (typeof window === "undefined") return null;
+  const host = window.location.hostname;
+  const m = host.match(/^([^.]+)\.moleculesai\.app$/);
+  return m ? m[1] : null;
+}
diff --git a/canvas/src/components/tabs/chat/AttachmentPreview.tsx b/canvas/src/components/tabs/chat/AttachmentPreview.tsx
index fbebcc04..794d23e2 100644
--- a/canvas/src/components/tabs/chat/AttachmentPreview.tsx
+++ b/canvas/src/components/tabs/chat/AttachmentPreview.tsx
@@ -17,6 +17,8 @@
 import type { ChatAttachment } from "./types";
 import { getAttachmentPreviewKind } from "./preview-kind";
 import { AttachmentImage } from "./AttachmentImage";
+import { AttachmentVideo } from "./AttachmentVideo";
+import { AttachmentAudio } from "./AttachmentAudio";
 import { AttachmentChip } from "./AttachmentViews";
 
 interface Props {
@@ -43,10 +45,25 @@ export function AttachmentPreview({ workspaceId, attachment, onDownload, tone }:
           tone={tone}
         />
       );
-    // PR-2 will add cases for video / audio.
-    // PR-3 will add cases for pdf / text.
     case "video":
+      return (
+        <AttachmentVideo
+          workspaceId={workspaceId}
+          attachment={attachment}
+          onDownload={onDownload}
+          tone={tone}
+        />
+      );
     case "audio":
+      return (
+        <AttachmentAudio
+          workspaceId={workspaceId}
+          attachment={attachment}
+          onDownload={onDownload}
+          tone={tone}
+        />
+      );
+    // PR-3 will add cases for pdf / text.
     case "pdf":
     case "text":
     case "file":
diff --git a/canvas/src/components/tabs/chat/AttachmentVideo.tsx b/canvas/src/components/tabs/chat/AttachmentVideo.tsx
new file mode 100644
index 00000000..0691006d
--- /dev/null
+++ b/canvas/src/components/tabs/chat/AttachmentVideo.tsx
@@ -0,0 +1,157 @@
+"use client";
+
+// AttachmentVideo — inline native HTML5 <video controls> player for
+// chat attachments (RFC #2991, PR-2).
+//
+// Why HTML5-native (vs custom JS player):
+//
+//   - Browser vendors ship hardware-accelerated decoders, captions,
+//     and fullscreen UI. We get all of it for free.
+//   - Native fullscreen via the <video> element's built-in button
+//     (no AttachmentLightbox needed for video — the browser does it).
+//   - Mobile-friendly: iOS / Android Safari + Chrome handle the
+//     pinch + scrub UX the user already knows.
+//
+// Auth model — identical to AttachmentImage:
+// platform-auth URIs need our cookie/token, so we fetch the bytes,
+// wrap in a Blob, hand the browser an ObjectURL via <video src=>.
+// External (http/https) URIs skip the fetch and use the raw URL.
+//
+// Memory caveat: a Blob holds the entire video in JS memory until
+// the bubble unmounts. For multi-hundred-MB videos this is bad. The
+// server caps single-file uploads at 25MB (chat_files.go), so we're
+// bounded; if larger files become a real shape, switch to streaming
+// via MediaSource or just `<video src=…>` with a credentials-aware
+// fetch via service worker. v2 if measured-needed.
+
+import { useState, useEffect, useRef } from "react";
+import type { ChatAttachment } from "./types";
+import { isPlatformAttachment, resolveAttachmentHref } from "./uploads";
+import { AttachmentChip } from "./AttachmentViews";
+
+interface Props {
+  workspaceId: string;
+  attachment: ChatAttachment;
+  onDownload: (a: ChatAttachment) => void;
+  tone: "user" | "agent";
+}
+
+type FetchState =
+  | { kind: "idle" }
+  | { kind: "loading" }
+  | { kind: "ready"; src: string }
+  | { kind: "error" };
+
+export function AttachmentVideo({ workspaceId, attachment, onDownload, tone }: Props) {
+  const [state, setState] = useState<FetchState>({ kind: "idle" });
+  const blobUrlRef = useRef<string | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    setState({ kind: "loading" });
+
+    if (!isPlatformAttachment(attachment.uri)) {
+      // External video (http/https) — let the browser stream it
+      // natively without the JS-blob detour.
+      const href = resolveAttachmentHref(workspaceId, attachment.uri);
+      if (!cancelled) setState({ kind: "ready", src: href });
+      return;
+    }
+
+    void (async () => {
+      try {
+        const href = resolveAttachmentHref(workspaceId, attachment.uri);
+        const headers: Record<string, string> = {};
+        const adminToken = process.env.NEXT_PUBLIC_ADMIN_TOKEN;
+        if (adminToken) headers["Authorization"] = `Bearer ${adminToken}`;
+        const slug = getTenantSlug();
+        if (slug) headers["X-Molecule-Org-Slug"] = slug;
+        const res = await fetch(href, {
+          headers,
+          credentials: "include",
+          // Videos are larger than images on average; give the request
+          // more headroom. The server's per-request body cap (50MB) is
+          // still the actual ceiling.
+          signal: AbortSignal.timeout(120_000),
+        });
+        if (!res.ok) {
+          if (!cancelled) setState({ kind: "error" });
+          return;
+        }
+        const blob = await res.blob();
+        const url = URL.createObjectURL(blob);
+        blobUrlRef.current = url;
+        if (cancelled) {
+          URL.revokeObjectURL(url);
+          return;
+        }
+        setState({ kind: "ready", src: url });
+      } catch {
+        if (!cancelled) setState({ kind: "error" });
+      }
+    })();
+
+    return () => {
+      cancelled = true;
+      if (blobUrlRef.current) {
+        URL.revokeObjectURL(blobUrlRef.current);
+        blobUrlRef.current = null;
+      }
+    };
+  }, [workspaceId, attachment.uri]);
+
+  if (state.kind === "error") {
+    return <AttachmentChip attachment={attachment} onDownload={onDownload} tone={tone} />;
+  }
+  if (state.kind === "idle" || state.kind === "loading") {
+    return (
+      <div
+        className="rounded-md border border-line/50 bg-surface-card/40 animate-pulse"
+        style={{ width: 320, height: 180 }}
+        aria-label={`Loading ${attachment.name}`}
+      />
+    );
+  }
+
+  return (
+    <div
+      className={`inline-block rounded-lg overflow-hidden border ${
+        tone === "user" ? "border-blue-400/30" : "border-line/50"
+      }`}
+    >
+      <video
+        controls
+        // preload="metadata" so the browser fetches just enough to
+        // show duration + first frame thumbnail without streaming
+        // the whole file before the user clicks play.
+        preload="metadata"
+        // playsInline keeps mobile Safari from auto-fullscreening
+        // on play; the user can still hit the native fullscreen
+        // button (or PiP on Chrome) if they want.
+        playsInline
+        // Native fullscreen via the <video> control bar; no
+        // AttachmentLightbox needed for video.
+        src={state.src}
+        // Cap thumbnail / inline display so the bubble doesn't blow
+        // up vertical layout for tall portrait clips. The native
+        // fullscreen button uses the original aspect ratio.
+        style={{ maxWidth: 320, maxHeight: 240, display: "block" }}
+        // Bytes that aren't actually a valid video (corrupt blob,
+        // wrong Content-Type) fail load → swap to chip.
+        onError={() => setState({ kind: "error" })}
+      >
+        <track kind="captions" />
+        {attachment.name}
+      </video>
+    </div>
+  );
+}
+
+// Internal helper — same shape as AttachmentImage's. Lifted to a
+// shared util in PR-2.5 if a third caller needs it (PDF, audio).
+function getTenantSlug(): string | null {
+  if (typeof window === "undefined") return null;
+  const host = window.location.hostname;
+  const m = host.match(/^([^.]+)\.moleculesai\.app$/);
+  return m ? m[1] : null;
+}
diff --git a/canvas/src/components/tabs/chat/__tests__/AttachmentPreview.test.tsx b/canvas/src/components/tabs/chat/__tests__/AttachmentPreview.test.tsx
index 0487d60d..5eae3e3f 100644
--- a/canvas/src/components/tabs/chat/__tests__/AttachmentPreview.test.tsx
+++ b/canvas/src/components/tabs/chat/__tests__/AttachmentPreview.test.tsx
@@ -154,6 +154,73 @@ describe("AttachmentPreview dispatch", () => {
     });
   });
 
+  // ─── PR-2: video / audio dispatch ───────────────────────────────
+
+  it("kind=video → renders <video controls> after fetch resolves", async () => {
+    fetchMock.mockResolvedValue({
+      ok: true,
+      blob: async () => new Blob(["fake-mp4"], { type: "video/mp4" }),
+    });
+    preview({ uri: "workspace:/workspace/clip.mp4", name: "clip.mp4", mimeType: "video/mp4" });
+    // Loading placeholder first.
+    expect(await screen.findByLabelText(/Loading clip\.mp4/i)).toBeTruthy();
+    // After the blob resolves, a <video> element with controls=true
+    // is in the DOM. Use a tag query — there's no built-in role for
+    // <video>, but the element is unambiguous in the bubble.
+    await waitFor(() => {
+      const v = document.querySelector("video");
+      expect(v).not.toBeNull();
+      // controls attribute pinned — without it the user can't play.
+      expect(v?.hasAttribute("controls")).toBe(true);
+      // src is the blob URL we minted.
+      expect((v as HTMLVideoElement).src).toBe("blob:test-url");
+    });
+    // Chip MUST NOT render — proves dispatch routed to video, not file.
+    expect(screen.queryByTitle(/Download clip\.mp4/i)).toBeNull();
+  });
+
+  it("kind=video fetch fails → falls back to AttachmentChip", async () => {
+    fetchMock.mockResolvedValue({ ok: false, status: 404 });
+    preview({ uri: "workspace:/workspace/missing.mp4", name: "missing.mp4", mimeType: "video/mp4" });
+    await waitFor(() => {
+      expect(screen.getByTitle(/Download missing\.mp4/i)).toBeTruthy();
+    });
+  });
+
+  it("kind=video by extension fallback (no mime) → video path", async () => {
+    fetchMock.mockReturnValue(new Promise(() => {}));
+    preview({ uri: "workspace:/workspace/recording.webm", name: "recording.webm" });
+    expect(await screen.findByLabelText(/Loading recording\.webm/i)).toBeTruthy();
+  });
+
+  it("kind=audio → renders <audio controls> with filename label", async () => {
+    fetchMock.mockResolvedValue({
+      ok: true,
+      blob: async () => new Blob(["fake-mp3"], { type: "audio/mpeg" }),
+    });
+    preview({ uri: "workspace:/workspace/song.mp3", name: "song.mp3", mimeType: "audio/mpeg" });
+    await waitFor(() => {
+      const a = document.querySelector("audio");
+      expect(a).not.toBeNull();
+      expect(a?.hasAttribute("controls")).toBe(true);
+      expect((a as HTMLAudioElement).src).toBe("blob:test-url");
+    });
+    // Filename label pinned: helps the user know what they're hearing
+    // BEFORE pressing play. Multiple matches — `<span>` text and the
+    // `<audio>`'s fallback `{name}` text node — so getAllByText.
+    expect(screen.getAllByText("song.mp3").length).toBeGreaterThan(0);
+  });
+
+  it("kind=audio fetch fails → falls back to chip", async () => {
+    fetchMock.mockResolvedValue({ ok: false, status: 403 });
+    preview({ uri: "workspace:/workspace/locked.wav", name: "locked.wav", mimeType: "audio/wav" });
+    await waitFor(() => {
+      expect(screen.getByTitle(/Download locked\.wav/i)).toBeTruthy();
+    });
+  });
+
+  // ─── universal-fallback regression ─────────────────────────────────
+
   it("kind=file is the universal fallback for unknown MIME (regression: don't try to preview a zip)", () => {
     // Critical safety: agent could attach a misnamed file. Pre-fix
     // the chip path was unconditional; we want unknown MIME to