diff --git a/src/agents/bash-process-registry.ts b/src/agents/bash-process-registry.ts
index 0e84065c7f2..10b08c0e3ee 100644
--- a/src/agents/bash-process-registry.ts
+++ b/src/agents/bash-process-registry.ts
@@ -23,6 +23,9 @@ export type SessionStdin = {
   // When backed by a real Node stream (child.stdin), this exists; for PTY wrappers it may not.
   destroy?: () => void;
   destroyed?: boolean;
+  writable?: boolean;
+  writableEnded?: boolean;
+  writableFinished?: boolean;
 };
 
 export interface ProcessSession {