diff --git a/packages/core/src/tool/plugin/shell.ts b/packages/core/src/tool/plugin/shell.ts
index 8a8ce3d707b0..16fe6a5f7749 100644
--- a/packages/core/src/tool/plugin/shell.ts
+++ b/packages/core/src/tool/plugin/shell.ts
@@ -176,7 +176,12 @@ export const Plugin = {
                           agent: context.agent,
                           source,
                         })
-                      if ((yield* fsUtil.stat(target.canonical)).type !== "Directory")
+                      const workdir = yield* fsUtil.stat(target.canonical).pipe(
+                        Effect.catchReason("PlatformError", "NotFound", () =>
+                          Effect.fail(new Error(`Working directory does not exist: ${target.canonical}`)),
+                        ),
+                      )
+                      if (workdir.type !== "Directory")
                         return yield* Effect.fail(new Error(`Working directory is not a directory: ${target.canonical}`))
                     }),
                 )
diff --git a/packages/core/test/tool-shell.test.ts b/packages/core/test/tool-shell.test.ts
index 64ea83996054..dfee4e12448d 100644
--- a/packages/core/test/tool-shell.test.ts
+++ b/packages/core/test/tool-shell.test.ts
@@ -257,6 +257,31 @@ describe("ShellTool", () => {
     ),
   )
 
+  it.live("reports a missing workdir", () =>
+    Effect.acquireUseRelease(
+      Effect.promise(() => tmpdir()),
+      (tmp) => {
+        reset()
+        return withSession(tmp.path, (registry) =>
+          executeTool(registry, call({ command: cwdCommand, workdir: "missing" })),
+        ).pipe(
+          Effect.andThen((settled) =>
+            Effect.sync(() =>
+              expect(settled).toEqual({
+                status: "error",
+                error: {
+                  type: "unknown",
+                  message: `Working directory does not exist: ${path.join(tmp.path, "missing")}`,
+                },
+              }),
+            ),
+          ),
+        )
+      },
+      (tmp) => Effect.promise(() => tmp[Symbol.asyncDispose]().then(() => undefined)),
+    ),
+  )
+
   it.live("permissions compound commands separately", () =>
     Effect.acquireUseRelease(
       Effect.promise(() => tmpdir()),