workdir: project occupancy from links

web/workspace/src/lib/workspace/sidebar/types.ts

@@ -115,6 +115,14 @@ export type WorkingDirectoryRepositoryOption = {
   default_selector?: string | null;
 };
 
+export type WorkingDirectoryOccupancy = {
+  runtime_id: string;
+  runtime_worker_id: number;
+  worker_id: string;
+  display_name: string;
+  linked_at: string;
+};
+
 export type WorkingDirectorySummary = {
   working_directory_id: string;
   repository_id: string;
@@ -125,6 +133,7 @@ export type WorkingDirectorySummary = {
   status: string;
   cleanliness?: string | null;
   primary_worker_id?: number | null;
+  occupied_by?: WorkingDirectoryOccupancy | null;
   cleanup_target: {
     kind: string;
     working_directory_id: string;

web/workspace/src/lib/workspace/sidebar/worker-launch.test.ts

@@ -86,6 +86,40 @@ Deno.test("defaultWorkerLaunchForm chooses active runtime, coder profile, reposi
   assertEquals(form.working_directory_selector, "HEAD");
 });
 
+Deno.test("defaultWorkerLaunchForm skips occupied working directories", () => {
+  const form = defaultWorkerLaunchForm(
+    {
+      ...options,
+      working_directories: [
+        {
+          ...options.working_directories[0],
+          occupied_by: {
+            runtime_id: "embedded",
+            runtime_worker_id: 12,
+            worker_id: "embedded:12",
+            display_name: "Worker 12",
+            linked_at: "2026-07-24T00:00:00Z",
+          },
+        },
+      ],
+    },
+    {
+      runtime_id: "",
+      display_name: "",
+      profile: "",
+      initial_text: "hello",
+      working_directory_id: "",
+      working_directory_repository_id: "",
+      working_directory_selector: "",
+      relative_cwd: "",
+    },
+  );
+
+  assertEquals(form.working_directory_id, "");
+  assertEquals(form.working_directory_repository_id, "repo");
+  assertEquals(form.working_directory_selector, "HEAD");
+});
+
 Deno.test("buildBrowserCreateWorkerRequest sends working_directory id and relative cwd only", () => {
   const request = buildBrowserCreateWorkerRequest({
     runtime_id: "embedded",

web/workspace/src/lib/workspace/sidebar/worker-launch.ts

@@ -38,7 +38,8 @@ export function defaultWorkerLaunchForm(
   const availableWorkingDirectories = options?.working_directories.filter((directory) =>
     directory.status === "active" &&
     directory.cleanliness === "clean" &&
-    directory.primary_worker_id == null
+    directory.primary_worker_id == null &&
+    directory.occupied_by == null
   ) ?? [];
   const selectedRuntime = current.runtime_id
     ? options?.runtimes.find((runtime) => runtime.runtime_id === current.runtime_id)

web/workspace/src/routes/w/[workspaceId]/settings/runtimes/[runtimeId]/workdirs/+page.svelte

@@ -129,6 +129,7 @@
             <th>Commit</th>
             <th>Status</th>
             <th>Cleanliness</th>
+            <th>Occupied by</th>
             <th>Action</th>
           </tr>
         </thead>
@@ -142,6 +143,14 @@
               <td><code>{commitLabel(workdir)}</code></td>
               <td>{workdir.status}</td>
               <td>{workdir.cleanliness ?? 'unknown'}</td>
+              <td>
+                {#if workdir.occupied_by}
+                  <span>{workdir.occupied_by.display_name}</span>
+                  <small>{workdir.occupied_by.runtime_id}:{workdir.occupied_by.runtime_worker_id}</small>
+                {:else}
+                  <span class="muted">—</span>
+                {/if}
+              </td>
               <td>
                 {#if cleanup}
                   <button

web/workspace/src/routes/w/[workspaceId]/workers/new/+page.svelte

@@ -50,7 +50,10 @@
     selectedRuntimeAllowsNoWorkdir
       ? []
       : (options?.working_directories ?? []).filter((directory) =>
-        directory.status === 'active' && directory.cleanliness === 'clean' && directory.primary_worker_id == null
+        directory.status === 'active' &&
+        directory.cleanliness === 'clean' &&
+        directory.primary_worker_id == null &&
+        directory.occupied_by == null
       ),
   );
   let canStartWorker = $derived(Boolean(