diff --git a/extension/background.js b/extension/background.js
index 51ac05b..5325fa6 100644
--- a/extension/background.js
+++ b/extension/background.js
@@ -232,7 +232,6 @@ Routes["/tabs/by-id"] = {
   }
 };
 
-// cannot use this wildcard trick w/o breaking the parent logic
 const tabIdDirectory = createWritableDirectory();
 Routes["/tabs/by-id/#TAB_ID"] = routeDefer(() => {
   const childrenRoute = routeDirectoryForChildren("/tabs/by-id/#TAB_ID");
@@ -246,9 +245,17 @@ Routes["/tabs/by-id/#TAB_ID"] = routeDefer(() => {
     }
   };
 });
-Routes["/tabs/by-id/#TAB_ID/:FILENAME"] = tabIdDirectory.routeForFilename;
-
+Routes["/tabs/by-id/#TAB_ID/:FILENAME"] = {
+  ...tabIdDirectory.routeForFilename,
+  async mknod(req) {
+    const ret = tabIdDirectory.routeForFilename.mknod(req);
+    // TODO: put icon on page
+    
+    return ret;
+  }
+};
 // TODO: can I trigger 1. nav to Finder and 2. nav to Terminal from toolbar click?
+// TODO: how can i let them drag files in?
 
 (function() {
   const routeForTab = (readHandler, writeHandler) => routeWithContents(async ({tabId}) => {
diff --git a/extension/embed-files.js b/extension/embed-files.js
new file mode 100644
index 0000000..0010fdf
--- /dev/null
+++ b/extension/embed-files.js
@@ -0,0 +1,112 @@
+// Content script that injects a file manager into tabs.
+
+document.body.insertAdjacentHTML('beforeend', `
+<style>
+.--tabfs-file-container .--tabfs-file {
+  position: absolute; top: 0; left: 0;
+  z-index: 10000;
+  cursor: move;
+  user-select: none; -webkit-user-select: none;
+  font: 12px system-ui, -apple-system;
+  background-color: white;
+}
+
+body.dragging::after {
+  background-color: green; opacity: 0.5; 
+  content: 'hello'; display: block;
+  position: fixed; top: 0; left: 0; right: 0; bottom: 0;
+}
+</style>
+
+<div class="--tabfs-file-container">
+</div>
+`);
+const container = document.getElementsByClassName('--tabfs-file-container')[0];
+
+const icons = {};
+
+let frontierX = 0, frontierY = 0;
+function addFile(name, x, y, file) {
+  if (!x) {
+    x = frontierX; frontierX += 64;
+    y = 0;
+  }
+
+  container.insertAdjacentHTML('beforeend', `
+<div class="--tabfs-file">${name}</div>
+`);
+  const icon = container.lastElementChild;
+  icon.style.left = x; icon.style.top = y; 
+
+  // from https://htmldom.dev/make-a-draggable-element/:
+
+  // The current position of mouse
+  let mouseX = 0;
+  let mouseY = 0;
+
+  // Handle the mousedown event
+  // that's triggered when user drags the element
+  const mouseDownHandler = function(e) {
+    // Get the current mouse position
+    mouseX = e.clientX;
+    mouseY = e.clientY;
+    
+    // Attach the listeners to `document`
+    document.addEventListener('mousemove', mouseMoveHandler);
+    document.addEventListener('mouseup', mouseUpHandler);
+
+    e.preventDefault();
+  };
+
+  const mouseMoveHandler = function(e) {
+    // How far the mouse has been moved
+    const dx = e.clientX - mouseX;
+    const dy = e.clientY - mouseY;
+
+    // Set the position of element
+    icon.style.top = `${icon.offsetTop + dy}px`; 
+    icon.style.left = `${icon.offsetLeft + dx}px`;
+
+    // Reassign the position of mouse
+    mouseX = e.clientX;
+    mouseY = e.clientY;
+
+    e.preventDefault();
+  };
+
+  const mouseUpHandler = function() {
+    // Remove the handlers of `mousemove` and `mouseup`
+    document.removeEventListener('mousemove', mouseMoveHandler);
+    document.removeEventListener('mouseup', mouseUpHandler);
+  };
+
+  icon.addEventListener('mousedown', mouseDownHandler);
+}
+
+['a.js', 'b.html', 'c.js'].forEach(name => addFile(name));
+
+// make the files draggable
+// remember their positions on rerender, like do a merge when we get a new set of files
+
+// from https://htmldom.dev/highlight-an-element-when-dragging-a-file-over-it/:
+
+document.body.addEventListener('dragenter', function(e) {
+  e.preventDefault();
+  e.target.classList.add('dragging');
+});
+document.body.addEventListener('dragover', function(e) {
+  e.preventDefault();
+});
+document.body.addEventListener('dragleave', function(e) {
+  e.preventDefault();
+  e.target.classList.remove('dragging');
+});
+
+document.body.addEventListener('drop', function(e) {
+  e.preventDefault();
+  e.target.classList.remove('dragging');
+
+  for (let file of [...e.dataTransfer.files]) {
+    addFile(file.name, e.clientX, e.clientY, file);
+  }
+});
diff --git a/extension/manifest.json b/extension/manifest.json
index c94608e..8b55454 100644
--- a/extension/manifest.json
+++ b/extension/manifest.json
@@ -17,6 +17,10 @@
     "scripts": ["vendor/browser-polyfill.js", "background.js"],
     "persistent": true
   },
+  "content_scripts": [{
+    "matches": ["*://*/*"],
+    "js": ["embed-files.js"]
+  }],
 
   "browser_specific_settings": {
     "gecko": {