diff --git a/web/workspace/src/lib/workspace/sidebar/types.ts b/web/workspace/src/lib/workspace/sidebar/types.ts
index 47b1c102..ddac6f58 100644
--- a/web/workspace/src/lib/workspace/sidebar/types.ts
+++ b/web/workspace/src/lib/workspace/sidebar/types.ts
@@ -119,7 +119,6 @@ export type WorkingDirectoryRepositoryOption = {
 
 export type WorkingDirectoryOccupancy = {
   runtime_id: string;
-  runtime_worker_id: number;
   worker_id: string;
   display_name: string;
   linked_at: string;
@@ -135,7 +134,7 @@ export type WorkingDirectorySummary = {
   materializer_kind: string;
   status: string;
   cleanliness?: string | null;
-  primary_worker_id?: number | null;
+  primary_worker_id?: string | null;
   occupied_by?: WorkingDirectoryOccupancy | null;
   cleanup_target: {
     kind: string;
diff --git a/web/workspace/src/lib/workspace/sidebar/worker-launch.test.ts b/web/workspace/src/lib/workspace/sidebar/worker-launch.test.ts
index c7dbcc95..4e76efaf 100644
--- a/web/workspace/src/lib/workspace/sidebar/worker-launch.test.ts
+++ b/web/workspace/src/lib/workspace/sidebar/worker-launch.test.ts
@@ -120,8 +120,7 @@ Deno.test("defaultWorkerLaunchForm skips occupied working directories", () => {
           ...options.working_directories[0],
           occupied_by: {
             runtime_id: "embedded",
-            runtime_worker_id: 12,
-            worker_id: "embedded:12",
+            worker_id: "0198f82e-6d90-7f15-a121-174a02e10e77",
             display_name: "Worker 12",
             linked_at: "2026-07-24T00:00:00Z",
           },
diff --git a/web/workspace/src/routes/w/[workspaceId]/settings/runtimes/[runtimeId]/workdirs/+page.svelte b/web/workspace/src/routes/w/[workspaceId]/settings/runtimes/[runtimeId]/workdirs/+page.svelte
index 3e27539a..62d58bb5 100644
--- a/web/workspace/src/routes/w/[workspaceId]/settings/runtimes/[runtimeId]/workdirs/+page.svelte
+++ b/web/workspace/src/routes/w/[workspaceId]/settings/runtimes/[runtimeId]/workdirs/+page.svelte
@@ -146,7 +146,7 @@
               <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>
+                  <small>{workdir.occupied_by.runtime_id}:{workdir.occupied_by.worker_id}</small>
                 {:else}
                   <span class="muted">—</span>
                 {/if}