fix(session): cleared session-scoped tool state

Cleared queued tool-choice directives and ACP always decisions after successful logical session transitions.

Added new-session and cross-session regression coverage for staged resolves and both ACP always decisions.

Fixes #4093

packages/coding-agent/src/session/agent-session.ts

@@ -4023,6 +4023,12 @@ export class AgentSession {
 		this.#rewoundToolResultIds.clear();
 	}
 
+	/** Drop mutable tool decisions and directives owned by the previous logical session. */
+	#clearSessionScopedToolState(): void {
+		this.#toolChoiceQueue.clear();
+		this.#tools.clearAcpPermissionDecisions();
+	}
+
 	/**
 	 * Rebuild checkpoint/rewind runtime state from the current branch. Handles two
 	 * cases surfaced by session resume, `switchSession()` reloading the same file,
@@ -5690,6 +5696,7 @@ export class AgentSession {
 			this.#bash.finishSessionTransition(bashTransition, sessionTransitioned);
 		}
 
+		this.#clearSessionScopedToolState();
 		this.#clearCheckpointRuntimeState();
 		this.setTodoPhases([]);
 		this.#freshProviderSessionId = undefined;
@@ -6810,6 +6817,9 @@ export class AgentSession {
 			if (switchingToDifferentSession) {
 				await this.#memory.resetContextForNewTranscript();
 			}
+			if (switchingToDifferentSession) {
+				this.#clearSessionScopedToolState();
+			}
 			this.#reconnectToAgent();
 			try {
 				await this.#sessionSwitchReconciler?.();

packages/coding-agent/src/session/session-tools.ts

@@ -158,6 +158,11 @@ export class SessionTools {
 		return this.#skillsSettings;
 	}
 
+	/** Drops cached per-session ACP `allow_always`/`reject_always` decisions. */
+	clearAcpPermissionDecisions(): void {
+		this.#acpPermissionDecisions.clear();
+	}
+
 	/** Re-wraps active and mounted tools after the ACP client changes. */
 	refreshAcpPermissionGates(): void {
 		this.#acpPermissionDecisions.clear();