feat(masking): enable tool output masking by default (#18564)

.gemini/settings.json

@@ -1,8 +1,5 @@
 {
   "experimental": {
-    "toolOutputMasking": {
-      "enabled": true
-    },
     "plan": true
   },
   "general": {

docs/cli/settings.md

@@ -125,10 +125,11 @@ they appear in the UI.
 
 ### Experimental
 
-| UI Label         | Setting                      | Description                                                                         | Default |
-| ---------------- | ---------------------------- | ----------------------------------------------------------------------------------- | ------- |
-| Use OSC 52 Paste | `experimental.useOSC52Paste` | Use OSC 52 sequence for pasting instead of clipboardy (useful for remote sessions). | `false` |
-| Plan             | `experimental.plan`          | Enable planning features (Plan Mode and tools).                                     | `false` |
+| UI Label                   | Setting                                  | Description                                                                         | Default |
+| -------------------------- | ---------------------------------------- | ----------------------------------------------------------------------------------- | ------- |
+| Enable Tool Output Masking | `experimental.toolOutputMasking.enabled` | Enables tool output masking to save tokens.                                         | `true`  |
+| Use OSC 52 Paste           | `experimental.useOSC52Paste`             | Use OSC 52 sequence for pasting instead of clipboardy (useful for remote sessions). | `false` |
+| Plan                       | `experimental.plan`                      | Enable planning features (Plan Mode and tools).                                     | `false` |
 
 ### Skills
 

docs/get-started/configuration.md

@@ -852,6 +852,28 @@ their corresponding top-level category object in your `settings.json` file.
 
 #### `experimental`
 
+- **`experimental.toolOutputMasking.enabled`** (boolean):
+  - **Description:** Enables tool output masking to save tokens.
+  - **Default:** `true`
+  - **Requires restart:** Yes
+
+- **`experimental.toolOutputMasking.toolProtectionThreshold`** (number):
+  - **Description:** Minimum number of tokens to protect from masking (most
+    recent tool outputs).
+  - **Default:** `50000`
+  - **Requires restart:** Yes
+
+- **`experimental.toolOutputMasking.minPrunableTokensThreshold`** (number):
+  - **Description:** Minimum prunable tokens required to trigger a masking pass.
+  - **Default:** `30000`
+  - **Requires restart:** Yes
+
+- **`experimental.toolOutputMasking.protectLatestTurn`** (boolean):
+  - **Description:** Ensures the absolute latest turn is never masked,
+    regardless of token count.
+  - **Default:** `true`
+  - **Requires restart:** Yes
+
 - **`experimental.enableAgents`** (boolean):
   - **Description:** Enable local and remote subagents. Warning: Experimental
     feature, uses YOLO mode for subagents

packages/cli/src/config/settingsSchema.ts

@@ -1471,7 +1471,7 @@ const SETTINGS_SCHEMA = {
         label: 'Tool Output Masking',
         category: 'Experimental',
         requiresRestart: true,
-        ignoreInDocs: true,
+        ignoreInDocs: false,
         default: {},
         description:
           'Advanced settings for tool output masking to manage context window efficiency.',
@@ -1482,9 +1482,9 @@ const SETTINGS_SCHEMA = {
             label: 'Enable Tool Output Masking',
             category: 'Experimental',
             requiresRestart: true,
-            default: false,
+            default: true,
             description: 'Enables tool output masking to save tokens.',
-            showInDialog: false,
+            showInDialog: true,
           },
           toolProtectionThreshold: {
             type: 'number',

packages/core/src/config/config.ts

@@ -758,7 +758,7 @@ export class Config {
     this.modelAvailabilityService = new ModelAvailabilityService();
     this.experimentalJitContext = params.experimentalJitContext ?? false;
     this.toolOutputMasking = {
-      enabled: params.toolOutputMasking?.enabled ?? false,
+      enabled: params.toolOutputMasking?.enabled ?? true,
       toolProtectionThreshold:
         params.toolOutputMasking?.toolProtectionThreshold ??
         DEFAULT_TOOL_PROTECTION_THRESHOLD,

schemas/settings.schema.json

@@ -1439,8 +1439,8 @@
             "enabled": {
               "title": "Enable Tool Output Masking",
               "description": "Enables tool output masking to save tokens.",
-              "markdownDescription": "Enables tool output masking to save tokens.\n\n- Category: `Experimental`\n- Requires restart: `yes`\n- Default: `false`",
-              "default": false,
+              "markdownDescription": "Enables tool output masking to save tokens.\n\n- Category: `Experimental`\n- Requires restart: `yes`\n- Default: `true`",
+              "default": true,
               "type": "boolean"
             },
             "toolProtectionThreshold": {