diff --git a/smoke-tests/tests/proxy-python.test.ts b/smoke-tests/tests/proxy-python.test.ts
index d75f254d4..62cc75cd0 100644
--- a/smoke-tests/tests/proxy-python.test.ts
+++ b/smoke-tests/tests/proxy-python.test.ts
@@ -53,7 +53,7 @@ except urllib.error.URLError as e:
 describe('python through the credential proxy (strict TLS verification)', () => {
   test.skipIf(SKIP)('urllib completes a strict-verified MITM request (installed CLI)', () => {
     const result = runVarlock(
-      ['proxy', 'run', '--', PYTHON!, '-c', PYTHON_CLIENT],
+      ['proxy', 'run', '--new', '--', PYTHON!, '-c', PYTHON_CLIENT],
       { cwd: 'smoke-test-proxy' },
     );
 
@@ -68,7 +68,7 @@ describe('python through the credential proxy (strict TLS verification)', () =>
     // The bundled/compiled binary is the risky artifact for cert generation
     // (module init order differs from bun run / vitest), so prove it there too.
     const result = runBinary(
-      ['proxy', 'run', '--', PYTHON!, '-c', PYTHON_CLIENT],
+      ['proxy', 'run', '--new', '--', PYTHON!, '-c', PYTHON_CLIENT],
       { cwd: 'smoke-test-proxy' },
     );
 
diff --git a/smoke-tests/tests/proxy-signals.test.ts b/smoke-tests/tests/proxy-signals.test.ts
index ae2d90760..3c6798712 100644
--- a/smoke-tests/tests/proxy-signals.test.ts
+++ b/smoke-tests/tests/proxy-signals.test.ts
@@ -13,11 +13,13 @@ const SKIP = process.platform === 'win32';
  * Spawn `varlock proxy run -- <command>`, wait until the child prints a `ready` marker,
  * send `signal` to the varlock process itself, and resolve once it exits.
  * stdin is left non-interactive so varlock runs the child in its own process group.
+ * `--new` keeps it from attaching to a proxy session another test file started in the same
+ * fixture dir (it can be shutting down and refuse the connection).
  */
 function runAndSignal(command: Array<string>, signal: NodeJS.Signals, env?: Record<string, string>) {
   return new Promise<{ output: string; code: number | null; signal: NodeJS.Signals | null }>(
     (resolve, reject) => {
-      const child = spawn(process.execPath, [VARLOCK_CLI, 'proxy', 'run', '--', ...command], {
+      const child = spawn(process.execPath, [VARLOCK_CLI, 'proxy', 'run', '--new', '--', ...command], {
         cwd: PROXY_CWD,
         stdio: ['ignore', 'pipe', 'pipe'],
         env: { ...process.env, ...env },