diff --git a/plugins/provider-acp/src/bridge/bridge.ts b/plugins/provider-acp/src/bridge/bridge.ts
index 40d7638c8..9e17152b6 100644
--- a/plugins/provider-acp/src/bridge/bridge.ts
+++ b/plugins/provider-acp/src/bridge/bridge.ts
@@ -326,9 +326,11 @@ function emitSessionError(session: AcpThreadSession, message: string): void {
 }
 
 function resolveBridgeProcessArgsForMcpServer(): string[] {
-  const entryPoint = process.argv[1]
-    ? resolve(process.argv[1])
-    : fileURLToPath(import.meta.url);
+  // The bridge module itself (the `bb.host` artifact, or bridge.ts from
+  // source), never process.argv[1]: since the provider-bridge bootstrap spawns
+  // every bridge, argv[1] is the bootstrap, whose argv contract rejects
+  // `--mcp-stdio` and exits before serving a single tool.
+  const entryPoint = fileURLToPath(import.meta.url);
   return [...process.execArgv, entryPoint, "--mcp-stdio"];
 }