diff --git a/src/auto-reply/reply/directive-handling.impl.ts b/src/auto-reply/reply/directive-handling.impl.ts
index 463cb42d67..4b07073272 100644
--- a/src/auto-reply/reply/directive-handling.impl.ts
+++ b/src/auto-reply/reply/directive-handling.impl.ts
@@ -309,11 +309,7 @@ export async function handleDirectiveOnly(params: {
   let reasoningChanged =
     directives.hasReasoningDirective && directives.reasoningLevel !== undefined;
   if (directives.hasThinkDirective && directives.thinkLevel) {
-    if (directives.thinkLevel === "off") {
-      delete sessionEntry.thinkingLevel;
-    } else {
-      sessionEntry.thinkingLevel = directives.thinkLevel;
-    }
+    sessionEntry.thinkingLevel = directives.thinkLevel;
   }
   if (shouldDowngradeXHigh) {
     sessionEntry.thinkingLevel = "high";
diff --git a/src/auto-reply/reply/directive-handling.persist.ts b/src/auto-reply/reply/directive-handling.persist.ts
index 0e700238b3..225cae0814 100644
--- a/src/auto-reply/reply/directive-handling.persist.ts
+++ b/src/auto-reply/reply/directive-handling.persist.ts
@@ -82,11 +82,7 @@ export async function persistInlineDirectives(params: {
     let updated = false;
 
     if (directives.hasThinkDirective && directives.thinkLevel) {
-      if (directives.thinkLevel === "off") {
-        delete sessionEntry.thinkingLevel;
-      } else {
-        sessionEntry.thinkingLevel = directives.thinkLevel;
-      }
+      sessionEntry.thinkingLevel = directives.thinkLevel;
       updated = true;
     }
     if (directives.hasVerboseDirective && directives.verboseLevel) {
diff --git a/src/commands/agent.ts b/src/commands/agent.ts
index 4c08d75df6..023ca94b46 100644
--- a/src/commands/agent.ts
+++ b/src/commands/agent.ts
@@ -222,11 +222,7 @@ export async function agentCommand(
         sessionEntry ?? { sessionId, updatedAt: Date.now() };
       const next: SessionEntry = { ...entry, sessionId, updatedAt: Date.now() };
       if (thinkOverride) {
-        if (thinkOverride === "off") {
-          delete next.thinkingLevel;
-        } else {
-          next.thinkingLevel = thinkOverride;
-        }
+        next.thinkingLevel = thinkOverride;
       }
       applyVerboseOverride(next, verboseOverride);
       sessionStore[sessionKey] = next;
diff --git a/src/gateway/sessions-patch.ts b/src/gateway/sessions-patch.ts
index ba2d7bbc03..c5240b5d17 100644
--- a/src/gateway/sessions-patch.ts
+++ b/src/gateway/sessions-patch.ts
@@ -124,6 +124,7 @@ export async function applySessionsPatchToStore(params: {
   if ("thinkingLevel" in patch) {
     const raw = patch.thinkingLevel;
     if (raw === null) {
+      // Clear the override and fall back to model default
       delete next.thinkingLevel;
     } else if (raw !== undefined) {
       const normalized = normalizeThinkLevel(String(raw));
@@ -134,11 +135,7 @@ export async function applySessionsPatchToStore(params: {
           `invalid thinkingLevel (use ${formatThinkingLevels(hintProvider, hintModel, "|")})`,
         );
       }
-      if (normalized === "off") {
-        delete next.thinkingLevel;
-      } else {
-        next.thinkingLevel = normalized;
-      }
+      next.thinkingLevel = normalized;
     }
   }