fix(mount): sync before starting daemon

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@agent-relay/sandbox",
-  "version": "0.1.9",
+  "version": "0.1.10",
   "description": "Provider-agnostic sandbox runtimes and orchestration for agent workloads.",
   "license": "Apache-2.0",
   "type": "module",

src/orchestrator.start-mount.test.ts

@@ -39,6 +39,25 @@ function recordingRuntime() {
  * their first real page — see AgentWorkforce/sandbox-router#11.
  */
 describe("startMount initial-sync idle budget", () => {
+  it("finishes the one-shot initial sync before starting the daemon", async () => {
+    const { orchestrator, commands } = recordingRuntime();
+    await orchestrator.startMount({ id: "sbx" }, MOUNT);
+
+    const initialSyncIndex = commands.findIndex((command) =>
+      command.includes("relayfile-initial-sync-exit:"),
+    );
+    const daemonIndex = commands.findIndex((command) =>
+      command.includes("nohup relayfile-mount"),
+    );
+
+    assert.notEqual(initialSyncIndex, -1, "initial sync was never launched");
+    assert.notEqual(daemonIndex, -1, "daemon was never started");
+    assert.ok(
+      initialSyncIndex < daemonIndex,
+      "daemon must not hold the mount lease while one-shot initial sync runs",
+    );
+  });
+
   it("defaults to 90s, matching relayfile's own bootstrap idle timeout", async () => {
     const { orchestrator, commands } = recordingRuntime();
     await orchestrator.startMount({ id: "sbx" }, MOUNT);

src/orchestrator.ts

@@ -206,21 +206,13 @@ export class SandboxOrchestrator<Handle> {
     const initialSyncIdleTimeoutSeconds = relayfileBootstrapIdleTimeoutSeconds(
       idleTimeoutMs / 1000,
     );
-    const start = await this.runtime.runScript(handle, {
-      command: withRelayfileBootstrapIdleTimeout(
-        buildRelayfileMountStartShell(config),
-        initialSyncIdleTimeoutSeconds,
-      ),
-      cwd,
-    });
-    if (start.exitCode !== 0) {
-      throw new Error(`Failed to start relayfile mount: ${start.output}`);
-    }
-
     // The initial sync can outlive any single exec (Daytona's proxy read
     // timeout is ~120s and callers wrap execs in client-side fail-fasts), so
     // it runs detached in the sandbox — keeping the in-sandbox idle watchdog
-    // — while we poll its exit sentinel with short, idempotent execs.
+    // — while we poll its exit sentinel with short, idempotent execs. Complete
+    // it before starting the daemon: both commands acquire the same per-root
+    // mount lease, and the exit sentinel is written only after the one-shot
+    // supervisor has exited and released that lease.
     const initialSyncRun = { runId: relayfileInitialSyncRunId() };
     const launch = await this.runtime.runScript(handle, {
       command: withRelayfileBootstrapIdleTimeout(
@@ -294,6 +286,17 @@ export class SandboxOrchestrator<Handle> {
       await sleepMs(pollIntervalMs);
     }
 
+    const start = await this.runtime.runScript(handle, {
+      command: withRelayfileBootstrapIdleTimeout(
+        buildRelayfileMountStartShell(config),
+        initialSyncIdleTimeoutSeconds,
+      ),
+      cwd,
+    });
+    if (start.exitCode !== 0) {
+      throw new Error(`Failed to start relayfile mount: ${start.output}`);
+    }
+
     const pid = start.output.trim().split(/\s+/).at(-1);
     return pid ? { pid } : {};
   }