diff --git a/Cotabby/Models/CustomRulesCatalog.swift b/Cotabby/Models/CustomRulesCatalog.swift
index 217d87d..c18c604 100644
--- a/Cotabby/Models/CustomRulesCatalog.swift
+++ b/Cotabby/Models/CustomRulesCatalog.swift
@@ -11,6 +11,16 @@ import Foundation
 /// is the single chokepoint that keeps stored rules bounded and de-duplicated regardless of whether
 /// they came from onboarding, settings, the palette, or a future import path.
 enum CustomRulesCatalog {
+    /// Master switch for the user-facing custom-rules feature. Temporarily `false`: the Open Source
+    /// path now runs base models that cannot obey free-text instructions, and on every engine the
+    /// rule text tends to leak verbatim into the suggestion (issues #340 / #292) while no eval
+    /// measures adherence, so surfacing the feature is a net-negative promise right now. Hiding is
+    /// fully reversible: stored rules in `cotabbyCustomRules` are never deleted, the editor and
+    /// renderer code is kept, so flipping this back to `true` restores the feature once rules are
+    /// measured to actually influence output. Honored at three sites: `SuggestionRequestFactory`
+    /// (prompt injection), `WritingPaneView` (Settings surface), and `WelcomeView` (onboarding step).
+    static let isUserFacingEnabled = false
+
     /// Caps protect the local model's limited context budget and guard against pasted essays.
     static let maxRules = 10
     static let maxRuleLength = 60
diff --git a/Cotabby/Support/SuggestionRequestFactory.swift b/Cotabby/Support/SuggestionRequestFactory.swift
index 0ec7dd3..9ab4601 100644
--- a/Cotabby/Support/SuggestionRequestFactory.swift
+++ b/Cotabby/Support/SuggestionRequestFactory.swift
@@ -43,8 +43,12 @@ enum SuggestionRequestFactory {
         )
         let completionLengthInstruction = settings.selectedWordCountPreset.promptInstruction
         let userName = activeUserName(settings: settings)
-        // Already normalized (trimmed/deduped/capped) by SuggestionSettingsModel.setRules.
-        let customRules = settings.customRules
+        // Custom rules are hidden from users (CustomRulesCatalog.isUserFacingEnabled == false): the
+        // base-model OSS path cannot obey free-text instructions and the rule text leaks into output,
+        // so injection is suppressed on every engine. Stored rules survive untouched, so flipping the
+        // flag restores this. When enabled, the value is already normalized (trimmed/deduped/capped)
+        // by SuggestionSettingsModel.setRules.
+        let customRules = CustomRulesCatalog.isUserFacingEnabled ? settings.customRules : []
         // The settings model length-caps but does NOT trim whitespace (trimming on every keystroke
         // would prevent the user from typing a space at the end of a word in the editor). Do the
         // trim here, once per request, and collapse a whitespace-only body back to nil so renderers
diff --git a/Cotabby/UI/Settings/Panes/WritingPaneView.swift b/Cotabby/UI/Settings/Panes/WritingPaneView.swift
index deb6880..92131d3 100644
--- a/Cotabby/UI/Settings/Panes/WritingPaneView.swift
+++ b/Cotabby/UI/Settings/Panes/WritingPaneView.swift
@@ -25,9 +25,12 @@ struct WritingPaneView: View {
 
             Section("Profile") {
                 VStack(alignment: .leading, spacing: 16) {
-                    // The caption introduces all three personalization inputs (name, languages,
-                    // rules) since each is passed to the AI, even though they live in separate cards.
-                    Text("Your name, languages, and rules are passed to the AI to help personalize your completions.")
+                    // Introduces the personalization inputs passed to the AI. The custom-rules input
+                    // is gated (CustomRulesCatalog.isUserFacingEnabled), so this copy and the Rules
+                    // section below are dropped together while the feature is hidden.
+                    Text(CustomRulesCatalog.isUserFacingEnabled
+                        ? "Your name, languages, and rules are passed to the AI to help personalize your completions."
+                        : "Your name and languages are passed to the AI to help personalize your completions.")
                         .font(.caption)
                         .foregroundStyle(.secondary)
                         .fixedSize(horizontal: false, vertical: true)
@@ -53,9 +56,13 @@ struct WritingPaneView: View {
                     .padding(.vertical, 6)
             }
 
-            Section("Rules") {
-                CustomRulesEditor(suggestionSettings: suggestionSettings, showsTitleHeader: false)
-                    .padding(.vertical, 6)
+            // Hidden while custom rules are gated off (CustomRulesCatalog.isUserFacingEnabled). The
+            // editor and its storage are intentionally kept so re-enabling is a one-line flip.
+            if CustomRulesCatalog.isUserFacingEnabled {
+                Section("Rules") {
+                    CustomRulesEditor(suggestionSettings: suggestionSettings, showsTitleHeader: false)
+                        .padding(.vertical, 6)
+                }
             }
         }
     }
diff --git a/Cotabby/UI/WelcomeView.swift b/Cotabby/UI/WelcomeView.swift
index b994320..75aa77f 100644
--- a/Cotabby/UI/WelcomeView.swift
+++ b/Cotabby/UI/WelcomeView.swift
@@ -204,7 +204,8 @@ extension WelcomeView {
                 canGoBack: true,
                 canContinue: true,
                 onBack: { step = .template },
-                onContinue: { step = .writingStyle }
+                // Skip the writing-style (custom rules) step when that feature is gated off.
+                onContinue: { step = CustomRulesCatalog.isUserFacingEnabled ? .writingStyle : .keybind }
             )
         case .writingStyle:
             WelcomeNavigation(
@@ -217,7 +218,7 @@ extension WelcomeView {
             WelcomeNavigation(
                 canGoBack: true,
                 canContinue: true,
-                onBack: { step = .writingStyle },
+                onBack: { step = CustomRulesCatalog.isUserFacingEnabled ? .writingStyle : .aboutYou },
                 onContinue: { step = .done }
             )
         case .welcome, .done:
@@ -241,8 +242,11 @@ private enum WelcomeStep: Int, Comparable {
         lhs.rawValue < rhs.rawValue
     }
 
-    /// Number of steps shown in the progress indicator (the middle, non-terminal steps).
-    static let totalProgressSteps = 5
+    /// Number of steps shown in the progress indicator (the middle, non-terminal steps). Drops to 4
+    /// when the custom-rules writing-style step is gated off (CustomRulesCatalog.isUserFacingEnabled).
+    static var totalProgressSteps: Int {
+        CustomRulesCatalog.isUserFacingEnabled ? 5 : 4
+    }
 
     /// 1-based position within the progress indicator, or `nil` for the intro/outro steps that
     /// intentionally sit outside the counted flow.
@@ -259,7 +263,8 @@ private enum WelcomeStep: Int, Comparable {
         case .writingStyle:
             return 4
         case .keybind:
-            return 5
+            // The 4th step when the writing-style step is gated off, otherwise the 5th.
+            return CustomRulesCatalog.isUserFacingEnabled ? 5 : 4
         }
     }