diff --git a/packages/extension/src/chat_bridge.ts b/packages/extension/src/chat_bridge.ts
index 48f52283..281c7e3c 100644
--- a/packages/extension/src/chat_bridge.ts
+++ b/packages/extension/src/chat_bridge.ts
@@ -389,7 +389,7 @@ export function handleAmicodeBridgeMessage(msg: unknown, io: BridgeIo): boolean
 
       // Build + reload is async; fire-and-forget from the sync handler.
       void (async () => {
-        const { exec } = await import("child_process");
+      const { exec } = await import("child_process");
         const buildResult = await new Promise<{ ok: boolean; error?: string }>((resolve) => {
           exec("bun run build", { cwd: amicodePath, timeout: 120_000 }, (err, _stdout, stderr) => {
             if (err) {
@@ -680,6 +680,123 @@ export function handleAmicodeBridgeMessage(msg: unknown, io: BridgeIo): boolean
     return true;
   }
 
+  // Devcontainer VSIX build: builds both repos using the pnpm-based workflow
+  // and emits a .vsix to the configured output path for manual installation.
+  if (msg.kind === "dev-tools-build-vsix") {
+    const opencodePath = typeof (msg as { opencodePath?: unknown }).opencodePath === "string"
+      ? (msg as unknown as { opencodePath: string }).opencodePath.trim().replace(/^~/, os.homedir())
+      : "";
+    const amicodePath = typeof (msg as { amicodePath?: unknown }).amicodePath === "string"
+      ? (msg as unknown as { amicodePath: string }).amicodePath.trim().replace(/^~/, os.homedir())
+      : "";
+    const outputPath = typeof (msg as { outputPath?: unknown }).outputPath === "string"
+      ? (msg as unknown as { outputPath: string }).outputPath.trim().replace(/^~/, os.homedir())
+      : "";
+
+    if (!opencodePath || !amicodePath || !outputPath) {
+      io.postToWebview({
+        source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+        state: "failed", error: "All three paths (opencode, amicode, output) must be set",
+      });
+      return true;
+    }
+
+    io.postToWebview({
+      source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+      state: "building",
+    });
+
+    void (async () => {
+      const { exec, execFile } = await import("child_process");
+      const run = (cmd: string, cwd: string): Promise<{ ok: boolean; error?: string; stdout?: string }> =>
+        new Promise((resolve) => {
+          exec(cmd, { cwd, timeout: 300_000, env: { ...process.env, NODE_OPTIONS: process.env.NODE_OPTIONS ?? "--max-old-space-size=4096", AMICODE_OPENCODE_SRC: opencodePath } },
+            (err, stdout, stderr) => {
+              if (err) resolve({ ok: false, error: stderr?.trim() || err.message });
+              else resolve({ ok: true, stdout: stdout?.trim() });
+            });
+        });
+
+      try {
+        // ── Step 1: Install opencode deps (bun-based repo) ──
+        const installOc = await run("bun install", opencodePath);
+        if (!installOc.ok) {
+          io.postToWebview({
+            source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+            state: "failed", error: `bun install (opencode) failed: ${installOc.error?.slice(0, 200)}`,
+          });
+          return;
+        }
+
+        // ── Step 2: Install amicode deps (pnpm-based repo) ──
+        const installAc = await run("pnpm install", amicodePath);
+        if (!installAc.ok) {
+          io.postToWebview({
+            source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+            state: "failed", error: `pnpm install (amicode) failed: ${installAc.error?.slice(0, 200)}`,
+          });
+          return;
+        }
+
+        // ── Step 3: Build extension bundle (esbuild) ──
+        const buildExt = await run("pnpm --filter amicode build", amicodePath);
+        if (!buildExt.ok) {
+          io.postToWebview({
+            source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+            state: "failed", error: `pnpm build failed: ${buildExt.error?.slice(0, 200)}`,
+          });
+          return;
+        }
+
+        // ── Step 4: Build opencode binary + vendor it ──
+        const buildOc = await run("pnpm --filter amicode opencode:build", amicodePath);
+        if (!buildOc.ok) {
+          io.postToWebview({
+            source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+            state: "failed", error: `opencode:build failed: ${buildOc.error?.slice(0, 200)}`,
+          });
+          return;
+        }
+
+        // ── Step 5: Package vsix ──
+        const extDir = path.join(amicodePath, "packages", "extension");
+        const vsixName = `amicode-${Date.now()}.vsix`;
+        const vsixDest = path.join(outputPath, vsixName);
+
+        fs.mkdirSync(outputPath, { recursive: true });
+
+        // Use execFile (no shell) to avoid command injection via outputPath
+        const packResult = await new Promise<{ ok: boolean; error?: string }>((resolve) => {
+          execFile("pnpm", ["exec", "vsce", "package", "--no-dependencies", "--allow-missing-repository", "-o", vsixDest],
+            { cwd: extDir, timeout: 300_000, env: { ...process.env, NODE_OPTIONS: process.env.NODE_OPTIONS ?? "--max-old-space-size=4096", AMICODE_OPENCODE_SRC: opencodePath } },
+            (err, _stdout, stderr) => {
+              if (err) resolve({ ok: false, error: stderr?.trim() || err.message });
+              else resolve({ ok: true });
+            });
+        });
+        if (!packResult.ok) {
+          io.postToWebview({
+            source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+            state: "failed", error: `vsce package failed: ${packResult.error?.slice(0, 200)}`,
+          });
+          return;
+        }
+
+        io.postToWebview({
+          source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+          state: "done", vsixPath: vsixDest,
+        });
+      } catch (e: unknown) {
+        io.postToWebview({
+          source: "amicode", kind: "dev-tools-build-vsix-status", tab: (msg as { tab?: string }).tab,
+          state: "failed", error: e instanceof Error ? e.message : "Unknown error",
+        });
+      }
+    })();
+
+    return true;
+  }
+
   // #351 reverse: Work Column Device Inspector → extension refresh
   if (msg.kind === "device:refresh" && typeof (msg as { device?: unknown }).device === "string") {
     void vscode.commands.executeCommand("amicode.device.refresh");
diff --git a/packages/extension/src/chat_panel.ts b/packages/extension/src/chat_panel.ts
index c4c41be1..a34adcfb 100644
--- a/packages/extension/src/chat_panel.ts
+++ b/packages/extension/src/chat_panel.ts
@@ -378,7 +378,7 @@ export class ChatPanel {
             replyClipboardImage(d.nonce);
             return;
           }
-          if (d && d.source === "amicode" && (d.kind === "command" || d.kind === "clipboard-request" || d.kind === "clipboard-write" || d.kind === "open-external" || d.kind === "open-file" || d.kind === "save-file" || d.kind === "set-default-model" || d.kind === "bug-filed" || d.kind === "bug-report-closed" || d.kind === "bug-report-poke" || d.kind === "dev-tools-update" || d.kind === "dev-tools-rebuild" || d.kind === "data-storage-query" || d.kind === "data-storage-update" || d.kind === "redo-onboarding" || d.kind === "device:refresh" || d.kind === "connections-credential" || d.kind === "connections-disconnect" || d.kind === "connections-revalidate" || d.kind === "connections-auth" || d.kind === "connections-choose-project" || d.kind === "connections-add-custom" || d.kind === "connections-remove" || d.kind === "app-ready")) {
+          if (d && d.source === "amicode" && (d.kind === "command" || d.kind === "clipboard-request" || d.kind === "clipboard-write" || d.kind === "open-external" || d.kind === "open-file" || d.kind === "save-file" || d.kind === "set-default-model" || d.kind === "bug-filed" || d.kind === "bug-report-closed" || d.kind === "bug-report-poke" || d.kind === "dev-tools-update" || d.kind === "dev-tools-rebuild" || d.kind === "dev-tools-build-vsix" || d.kind === "data-storage-query" || d.kind === "data-storage-update" || d.kind === "redo-onboarding" || d.kind === "device:refresh" || d.kind === "connections-credential" || d.kind === "connections-disconnect" || d.kind === "connections-revalidate" || d.kind === "connections-auth" || d.kind === "connections-choose-project" || d.kind === "connections-add-custom" || d.kind === "connections-remove" || d.kind === "app-ready")) {
             vscode.postMessage(d);
           }
           return;
@@ -387,7 +387,7 @@ export class ChatPanel {
         // (webview-internal origin, never the opencode origin). Forward only
         // our own envelopes, pinned to the opencode origin. #351 adds
         // run:*/device:* envelopes for the Work Column inspector tabs.
-        if (d && d.source === "amicode" && (d.kind === "theme" || d.kind === "clipboard" || d.kind === "navigate" || d.kind === "open-compute-connect" || d.kind === "open-bug-report" || d.kind === "close-bug-report" || d.kind === "dev-tools-status" || d.kind === "dev-tools-rebuild-status" || d.kind === "data-storage-defaults" || d.kind === "data-storage-status" || d.kind === "connections-credential-result" || d.kind === "connections-disconnect-result" || d.kind === "connections-revalidate-result" || d.kind === "connections-auth-result" || d.kind === "connections-choose-project-result" || d.kind === "connections-add-custom-result" || d.kind === "connections-remove-result" || (typeof d.kind === "string" && (d.kind.indexOf("run:") === 0 || d.kind.indexOf("device:") === 0)) || d.kind === "clipboard-image")) {
+        if (d && d.source === "amicode" && (d.kind === "theme" || d.kind === "clipboard" || d.kind === "navigate" || d.kind === "open-compute-connect" || d.kind === "open-bug-report" || d.kind === "close-bug-report" || d.kind === "dev-tools-status" || d.kind === "dev-tools-rebuild-status" || d.kind === "dev-tools-build-vsix-status" || d.kind === "data-storage-defaults" || d.kind === "data-storage-status" || d.kind === "connections-credential-result" || d.kind === "connections-disconnect-result" || d.kind === "connections-revalidate-result" || d.kind === "connections-auth-result" || d.kind === "connections-choose-project-result" || d.kind === "connections-add-custom-result" || d.kind === "connections-remove-result" || (typeof d.kind === "string" && (d.kind.indexOf("run:") === 0 || d.kind.indexOf("device:") === 0)) || d.kind === "clipboard-image")) {
           var f = document.querySelector("iframe");
           if (f && f.contentWindow) f.contentWindow.postMessage(d, ${origin});
         }
@@ -567,12 +567,12 @@ export class ChatPanel {
             replyClipboardImage(d.nonce);
             return;
           }
-          if (d && d.source === "amicode" && (d.kind === "command" || d.kind === "clipboard-request" || d.kind === "clipboard-write" || d.kind === "open-external" || d.kind === "open-file" || d.kind === "save-file" || d.kind === "set-default-model" || d.kind === "bug-filed" || d.kind === "bug-report-closed" || d.kind === "bug-report-poke" || d.kind === "dev-tools-update" || d.kind === "dev-tools-rebuild" || d.kind === "data-storage-query" || d.kind === "data-storage-update" || d.kind === "redo-onboarding" || d.kind === "device:refresh" || d.kind === "connections-credential" || d.kind === "connections-disconnect" || d.kind === "connections-revalidate" || d.kind === "connections-auth" || d.kind === "connections-choose-project" || d.kind === "connections-add-custom" || d.kind === "connections-remove" || d.kind === "app-ready")) {
+          if (d && d.source === "amicode" && (d.kind === "command" || d.kind === "clipboard-request" || d.kind === "clipboard-write" || d.kind === "open-external" || d.kind === "open-file" || d.kind === "save-file" || d.kind === "set-default-model" || d.kind === "bug-filed" || d.kind === "bug-report-closed" || d.kind === "bug-report-poke" || d.kind === "dev-tools-update" || d.kind === "dev-tools-rebuild" || d.kind === "dev-tools-build-vsix" || d.kind === "data-storage-query" || d.kind === "data-storage-update" || d.kind === "redo-onboarding" || d.kind === "device:refresh" || d.kind === "connections-credential" || d.kind === "connections-disconnect" || d.kind === "connections-revalidate" || d.kind === "connections-auth" || d.kind === "connections-choose-project" || d.kind === "connections-add-custom" || d.kind === "connections-remove" || d.kind === "app-ready")) {
             vscode.postMessage(d);
           }
           return;
         }
-        if (d && d.source === "amicode" && (d.kind === "theme" || d.kind === "clipboard" || d.kind === "navigate" || d.kind === "open-compute-connect" || d.kind === "open-bug-report" || d.kind === "close-bug-report" || d.kind === "dev-tools-status" || d.kind === "dev-tools-rebuild-status" || d.kind === "data-storage-defaults" || d.kind === "data-storage-status" || d.kind === "connections-credential-result" || d.kind === "connections-disconnect-result" || d.kind === "connections-revalidate-result" || d.kind === "connections-auth-result" || d.kind === "connections-choose-project-result" || d.kind === "connections-add-custom-result" || d.kind === "connections-remove-result" || (typeof d.kind === "string" && (d.kind.indexOf("run:") === 0 || d.kind.indexOf("device:") === 0)) || d.kind === "clipboard-image")) {
+        if (d && d.source === "amicode" && (d.kind === "theme" || d.kind === "clipboard" || d.kind === "navigate" || d.kind === "open-compute-connect" || d.kind === "open-bug-report" || d.kind === "close-bug-report" || d.kind === "dev-tools-status" || d.kind === "dev-tools-rebuild-status" || d.kind === "dev-tools-build-vsix-status" || d.kind === "data-storage-defaults" || d.kind === "data-storage-status" || d.kind === "connections-credential-result" || d.kind === "connections-disconnect-result" || d.kind === "connections-revalidate-result" || d.kind === "connections-auth-result" || d.kind === "connections-choose-project-result" || d.kind === "connections-add-custom-result" || d.kind === "connections-remove-result" || (typeof d.kind === "string" && (d.kind.indexOf("run:") === 0 || d.kind.indexOf("device:") === 0)) || d.kind === "clipboard-image")) {
           var f = document.querySelector("iframe");
           if (f && f.contentWindow) f.contentWindow.postMessage(d, origin);
         }