diff --git a/config.ts b/config.ts
index b885639..0581f69 100644
--- a/config.ts
+++ b/config.ts
@@ -58,7 +58,7 @@ export async function getOrg(
       }
 
       org = selectedOrg.value.slug;
-      console.log(`Selected organization '${selectedOrg.value.name}'`);
+      console.error(`Selected organization '${selectedOrg.value.name}'`);
     }
   }
 
@@ -144,7 +144,7 @@ export async function getApp(
       created = true;
     } else {
       app = selectedApp.value.slug;
-      console.log(`Selected application '${selectedApp.value.slug}'`);
+      console.error(`Selected application '${selectedApp.value.slug}'`);
     }
   }
 
@@ -314,7 +314,7 @@ async function writeConfig(
   );
 
   if (!configContent.config) {
-    console.log(
+    console.error(
       `Created configuration file at '${join(Deno.cwd(), "deno.jsonc")}'`,
     );
   }
diff --git a/sandbox/mod.ts b/sandbox/mod.ts
index f76c3da..e8e9f36 100644
--- a/sandbox/mod.ts
+++ b/sandbox/mod.ts
@@ -12,7 +12,10 @@ import { join } from "@std/path";
 import { Spinner } from "@std/cli/unstable-spinner";
 
 import {
+  error,
+  ExitCode,
   formatDuration,
+  isNonInteractive,
   parseSize,
   renderTemporalTimestamp,
   tablePrinter,
@@ -91,6 +94,26 @@ export const sandboxCreateCommand = new Command<SandboxContext>()
     config.noCreate();
     const org = await getOrg(options, config, options.org);
 
+    // A "session" timeout (the default) keeps the sandbox alive only for as long
+    // as this process — the *primary* client — stays connected, blocking on
+    // SIGINT. That is an inherently interactive construct: in non-interactive /
+    // CI mode the process must return promptly, and doing so would immediately
+    // destroy a session-scoped sandbox. Reject it up front (before creating an
+    // orphan) and steer the caller to an explicit, self-sufficient timeout.
+    const nonInteractive = isNonInteractive(options);
+    if (nonInteractive && options.timeout === "session") {
+      error(
+        options,
+        "Cannot create a sandbox with the default 'session' timeout in non-interactive mode: a session-scoped sandbox is destroyed as soon as this command exits.",
+        {
+          code: ExitCode.USAGE,
+          errorCode: "NON_INTERACTIVE_REQUIRED",
+          hint:
+            "Pass an explicit --timeout (e.g. --timeout 15m) so the sandbox outlives this command, then manage it with `sandbox kill`.",
+        },
+      );
+    }
+
     const quiet = options.timeout === "session";
     const token = await getAuth(options, quiet);
 
@@ -113,7 +136,7 @@ export const sandboxCreateCommand = new Command<SandboxContext>()
     if (
       (options.timeout === "session" || options.ssh) && !options.json
     ) {
-      console.log(`${green("✔")} Created sandbox with id '${sandbox.id}'`);
+      console.error(`${green("✔")} Created sandbox with id '${sandbox.id}'`);
     }
 
     if (options.copy) {
@@ -135,12 +158,8 @@ export const sandboxCreateCommand = new Command<SandboxContext>()
 
     if (options.exposeHttp) {
       const url = await sandbox.exposeHttp({ port: options.exposeHttp });
-      // In JSON mode this is progress, not the final result; keep stdout clean.
-      if (options.json) {
-        console.error(`Exposed port ${options.exposeHttp} to ${url}`);
-      } else {
-        console.log(`Exposed port ${options.exposeHttp} to ${url}`);
-      }
+      // Progress/status, not the command's data payload — keep stdout clean.
+      console.error(`Exposed port ${options.exposeHttp} to ${url}`);
     }
 
     const args = this.getLiteralArgs().length > 0
@@ -167,36 +186,45 @@ export const sandboxCreateCommand = new Command<SandboxContext>()
     await config.save();
 
     const stopMessage = "Stopping the sandbox...";
+
+    // Status chrome belongs on stderr so `--json` stdout stays a single payload.
+    const installKeepAlive = () => {
+      console.error("\nCtrl+C to stop the sandbox.");
+      Deno.addSignalListener("SIGINT", async () => {
+        console.error("\n" + stopMessage);
+        await sandbox.close();
+        Deno.exit();
+      });
+    };
+
+    const emitResult = () => {
+      if (options.json) {
+        writeJsonResult({ id: sandbox.id, org, timeout: options.timeout });
+      } else {
+        console.log(sandbox.id);
+      }
+    };
+
     if (options.ssh) {
       const success = await sshIntoSandbox(sandbox);
       if (success) {
         // Closes the sandbox only when ssh session was established and finished successfully
-        console.log("Disconnecting from the sandbox...");
+        console.error("Disconnecting from the sandbox...");
         await sandbox.close();
+      } else if (nonInteractive) {
+        // No TTY to attach an ssh session to: return the sandbox info and let
+        // its (explicit) timeout govern its lifetime instead of blocking.
+        emitResult();
+        Deno.exit();
       } else {
         // Otherwise, keep the sandbox running and wait for Ctrl+C
-        console.log("\nCtrl+C to stop the sandbox.");
-        Deno.addSignalListener("SIGINT", async () => {
-          console.log("\n" + stopMessage);
-          await sandbox.close();
-          Deno.exit();
-        });
+        installKeepAlive();
       }
     } else if (options.timeout === "session") {
-      // Otherwise, keep the sandbox running and wait for Ctrl+C
-      console.log("\nCtrl+C to stop the sandbox.");
-      Deno.addSignalListener("SIGINT", async () => {
-        console.log("\n" + stopMessage);
-        await sandbox.close();
-        Deno.exit();
-      });
+      // Interactive only — non-interactive session timeouts are rejected above.
+      installKeepAlive();
     } else {
-      if (options.json) {
-        writeJsonResult({ id: sandbox.id });
-      } else {
-        console.log(sandbox.id);
-      }
-
+      emitResult();
       Deno.exit();
     }
   }));
@@ -284,7 +312,7 @@ export const sandboxKillCommand = new Command<SandboxContext>()
     if (options.json) {
       writeJsonResult({ id: sandboxId, killed: res.success });
     } else if (res.success) {
-      console.log(`${green("✔")} Sandbox ${sandboxId} killed successfully.`);
+      console.error(`${green("✔")} Sandbox ${sandboxId} killed successfully.`);
     }
   }));
 
@@ -544,7 +572,7 @@ export const sandboxDeployCommand = new Command<SandboxContext>()
     if (options.json) {
       writeJsonResult({ id: sandboxId, app, deployed: true });
     } else {
-      console.log(
+      console.error(
         `${
           green("✔")
         } Successfully deployed sandbox '${sandboxId}' to app '${app}'.`,
@@ -602,7 +630,7 @@ async function sshIntoSandbox(sandbox: Sandbox): Promise<boolean> {
     stderr: "null",
   }).output();
   if (which.success) {
-    console.log(`ssh ${connectInfo}`);
+    console.error(`ssh ${connectInfo}`);
     const command = new Deno.Command("ssh", {
       args: [connectInfo],
       stdin: "inherit",
@@ -614,7 +642,7 @@ async function sshIntoSandbox(sandbox: Sandbox): Promise<boolean> {
     await sandbox.close();
     return true;
   } else {
-    console.log(
+    console.error(
       `Started ssh session. You can now connect to ${magenta(connectInfo)}
 
 Example:
diff --git a/sandbox/snapshot.ts b/sandbox/snapshot.ts
index 06acfa6..2dd55ae 100644
--- a/sandbox/snapshot.ts
+++ b/sandbox/snapshot.ts
@@ -102,7 +102,9 @@ export const snapshotsDeleteCommand = new Command<SandboxContext>()
     if (options.json) {
       writeJsonResult({ id: idOrSlug, deleted: true });
     } else {
-      console.log(`${green("✔")} Successfully deleted snapshot '${idOrSlug}'.`);
+      console.error(
+        `${green("✔")} Successfully deleted snapshot '${idOrSlug}'.`,
+      );
     }
   }));
 
diff --git a/sandbox/volumes.ts b/sandbox/volumes.ts
index 6abc6f5..3207004 100644
--- a/sandbox/volumes.ts
+++ b/sandbox/volumes.ts
@@ -118,7 +118,7 @@ export const volumesDeleteCommand = new Command<SandboxContext>()
     if (options.json) {
       writeJsonResult({ id: idOrSlug, deleted: true });
     } else {
-      console.log(`${green("✔")} Successfully deleted volume '${idOrSlug}'.`);
+      console.error(`${green("✔")} Successfully deleted volume '${idOrSlug}'.`);
     }
   }));
 
diff --git a/tests/agent.test.ts b/tests/agent.test.ts
index 64b3db8..a44b4cc 100644
--- a/tests/agent.test.ts
+++ b/tests/agent.test.ts
@@ -197,6 +197,33 @@ Deno.test("sandbox --help advertises --json and --non-interactive", async () =>
   assertStringIncludes(res.stdout, "--non-interactive");
 });
 
+Deno.test("sandbox create --json --non-interactive with default session timeout fails fast (no hang)", async () => {
+  // Regression for the create hang: the default `timeout=session` installs an
+  // interactive SIGINT keep-alive. In non-interactive mode that blocked forever
+  // instead of emitting JSON or exiting. It must now refuse up front with a
+  // USAGE envelope (exit 2) and a clean stdout, before any backend round-trip.
+  const res = await sandboxRaw(
+    "--json",
+    "--non-interactive",
+    "--token",
+    "obviously-invalid-token",
+    "--endpoint",
+    "http://127.0.0.1:1",
+    "create",
+    "--org",
+    "test",
+  );
+  assertEquals(res.code, 2, `unexpected exit; stderr: ${res.stderr}`);
+  assertEquals(
+    res.stdout.trim(),
+    "",
+    `stdout should stay clean: ${res.stdout}`,
+  );
+  const envelope = JSON.parse(res.stderr.trim().split("\n").pop()!);
+  assertEquals(envelope.error.code, "NON_INTERACTIVE_REQUIRED");
+  assertStringIncludes(envelope.error.hint, "--timeout");
+});
+
 Deno.test("sandbox list --json emits a structured error envelope, never a browser/hang", async () => {
   // Bad token + unreachable endpoint: the command must fail fast with a
   // machine-parseable envelope on stderr (and a clean stdout) rather than