Make compression threshold editable in the UI. (#12317)

Author: scidomino

docs/get-started/configuration-v1.md

@@ -473,21 +473,6 @@ a few things you can try in order of recommendation:
     "loadMemoryFromIncludeDirectories": true
     ```
 
-- **`chatCompression`** (object):
-  - **Description:** Controls the settings for chat history compression, both
-    automatic and when manually invoked through the /compress command.
-  - **Properties:**
-    - **`contextPercentageThreshold`** (number): A value between 0 and 1 that
-      specifies the token threshold for compression as a percentage of the
-      model's total token limit. For example, a value of `0.6` will trigger
-      compression when the chat history exceeds 60% of the token limit.
-  - **Example:**
-    ```json
-    "chatCompression": {
-      "contextPercentageThreshold": 0.6
-    }
-    ```
-
 - **`showLineNumbers`** (boolean):
   - **Description:** Controls whether line numbers are displayed in code blocks
     in the CLI output.

docs/get-started/configuration.md

@@ -245,13 +245,13 @@ their corresponding top-level category object in your `settings.json` file.
     example `{"run_shell_command": {"tokenBudget": 2000}}`
   - **Default:** `undefined`
 
-- **`model.chatCompression.contextPercentageThreshold`** (number):
+- **`model.compressionThreshold`** (number):
   - **Description:** Sets the threshold for chat history compression as a
-    percentage of the model's total token limit. This is a value between 0 and 1
+    fraction of the model's total token limit. This is a value between 0 and 1
     that applies to both automatic compression and the manual `/compress`
     command. For example, a value of `0.6` will trigger compression when the
     chat history exceeds 60% of the token limit.
-  - **Default:** `0.7`
+  - **Default:** `0.2`
 
 - **`model.skipNextSpeakerCheck`** (boolean):
   - **Description:** Skip the next speaker check.

packages/cli/src/config/config.test.ts

@@ -1545,7 +1545,7 @@ describe('loadCliConfig with includeDirectories', () => {
   });
 });
 
-describe('loadCliConfig chatCompression', () => {
+describe('loadCliConfig compressionThreshold', () => {
   beforeEach(() => {
     vi.resetAllMocks();
     vi.mocked(os.homedir).mockReturnValue('/mock/home/user');
@@ -1558,28 +1558,24 @@ describe('loadCliConfig chatCompression', () => {
     vi.restoreAllMocks();
   });
 
-  it('should pass chatCompression settings to the core config', async () => {
+  it('should pass settings to the core config', async () => {
     process.argv = ['node', 'script.js'];
     const argv = await parseArguments({} as Settings);
     const settings: Settings = {
       model: {
-        chatCompression: {
-          contextPercentageThreshold: 0.5,
-        },
+        compressionThreshold: 0.5,
       },
     };
     const config = await loadCliConfig(settings, 'test-session', argv);
-    expect(config.getChatCompression()).toEqual({
-      contextPercentageThreshold: 0.5,
-    });
+    expect(config.getCompressionThreshold()).toBe(0.5);
   });
 
-  it('should have undefined chatCompression if not in settings', async () => {
+  it('should have undefined compressionThreshold if not in settings', async () => {
     process.argv = ['node', 'script.js'];
     const argv = await parseArguments({} as Settings);
     const settings: Settings = {};
     const config = await loadCliConfig(settings, 'test-session', argv);
-    expect(config.getChatCompression()).toBeUndefined();
+    expect(config.getCompressionThreshold()).toBeUndefined();
   });
 });
 

packages/cli/src/config/config.ts

@@ -685,7 +685,7 @@ export async function loadCliConfig(
     noBrowser: !!process.env['NO_BROWSER'],
     summarizeToolOutput: settings.model?.summarizeToolOutput,
     ideMode,
-    chatCompression: settings.model?.chatCompression,
+    compressionThreshold: settings.model?.compressionThreshold,
     folderTrust,
     interactive,
     trustedFolder,

packages/cli/src/config/settings.test.ts

@@ -1104,15 +1104,15 @@ describe('Settings Loading and Merging', () => {
       });
     });
 
-    it('should merge chatCompression settings, with workspace taking precedence', () => {
+    it('should merge compressionThreshold settings, with workspace taking precedence', () => {
       (mockFsExistsSync as Mock).mockReturnValue(true);
       const userSettingsContent = {
         general: {},
-        model: { chatCompression: { contextPercentageThreshold: 0.5 } },
+        model: { compressionThreshold: 0.5 },
       };
       const workspaceSettingsContent = {
         general: {},
-        model: { chatCompression: { contextPercentageThreshold: 0.8 } },
+        model: { compressionThreshold: 0.8 },
       };
 
       (fs.readFileSync as Mock).mockImplementation(
@@ -1127,15 +1127,11 @@ describe('Settings Loading and Merging', () => {
 
       const settings = loadSettings(MOCK_WORKSPACE_DIR);
 
-      expect(settings.user.settings.model?.chatCompression).toEqual({
-        contextPercentageThreshold: 0.5,
-      });
-      expect(settings.workspace.settings.model?.chatCompression).toEqual({
-        contextPercentageThreshold: 0.8,
-      });
-      expect(settings.merged.model?.chatCompression).toEqual({
-        contextPercentageThreshold: 0.8,
-      });
+      expect(settings.user.settings.model?.compressionThreshold).toEqual(0.5);
+      expect(settings.workspace.settings.model?.compressionThreshold).toEqual(
+        0.8,
+      );
+      expect(settings.merged.model?.compressionThreshold).toEqual(0.8);
     });
 
     it('should merge output format settings, with workspace taking precedence', () => {
@@ -1162,13 +1158,13 @@ describe('Settings Loading and Merging', () => {
       expect(settings.merged.output?.format).toBe('json');
     });
 
-    it('should handle chatCompression when only in user settings', () => {
+    it('should handle compressionThreshold when only in user settings', () => {
       (mockFsExistsSync as Mock).mockImplementation(
         (p: fs.PathLike) => p === USER_SETTINGS_PATH,
       );
       const userSettingsContent = {
         general: {},
-        model: { chatCompression: { contextPercentageThreshold: 0.5 } },
+        model: { compressionThreshold: 0.5 },
       };
       (fs.readFileSync as Mock).mockImplementation(
         (p: fs.PathOrFileDescriptor) => {
@@ -1179,9 +1175,7 @@ describe('Settings Loading and Merging', () => {
       );
 
       const settings = loadSettings(MOCK_WORKSPACE_DIR);
-      expect(settings.merged.model?.chatCompression).toEqual({
-        contextPercentageThreshold: 0.5,
-      });
+      expect(settings.merged.model?.compressionThreshold).toEqual(0.5);
     });
 
     it('should have model as undefined if not in any settings file', () => {
@@ -1191,39 +1185,15 @@ describe('Settings Loading and Merging', () => {
       expect(settings.merged.model).toBeUndefined();
     });
 
-    it('should ignore chatCompression if contextPercentageThreshold is invalid', () => {
-      const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
-      (mockFsExistsSync as Mock).mockImplementation(
-        (p: fs.PathLike) => p === USER_SETTINGS_PATH,
-      );
-      const userSettingsContent = {
-        general: {},
-        model: { chatCompression: { contextPercentageThreshold: 1.5 } },
-      };
-      (fs.readFileSync as Mock).mockImplementation(
-        (p: fs.PathOrFileDescriptor) => {
-          if (p === USER_SETTINGS_PATH)
-            return JSON.stringify(userSettingsContent);
-          return '{}';
-        },
-      );
-
-      const settings = loadSettings(MOCK_WORKSPACE_DIR);
-      expect(settings.merged.model?.chatCompression).toEqual({
-        contextPercentageThreshold: 1.5,
-      });
-      warnSpy.mockRestore();
-    });
-
-    it('should deep merge chatCompression settings', () => {
+    it('should use user compressionThreshold if workspace does not define it', () => {
       (mockFsExistsSync as Mock).mockReturnValue(true);
       const userSettingsContent = {
         general: {},
-        model: { chatCompression: { contextPercentageThreshold: 0.5 } },
+        model: { compressionThreshold: 0.5 },
       };
       const workspaceSettingsContent = {
         general: {},
-        model: { chatCompression: {} },
+        model: {},
       };
 
       (fs.readFileSync as Mock).mockImplementation(
@@ -1238,9 +1208,7 @@ describe('Settings Loading and Merging', () => {
 
       const settings = loadSettings(MOCK_WORKSPACE_DIR);
 
-      expect(settings.merged.model?.chatCompression).toEqual({
-        contextPercentageThreshold: 0.5,
-      });
+      expect(settings.merged.model?.compressionThreshold).toEqual(0.5);
     });
 
     it('should merge includeDirectories from all scopes', () => {
@@ -2025,9 +1993,6 @@ describe('Settings Loading and Merging', () => {
         },
         model: {
           name: 'gemini-pro',
-          chatCompression: {
-            contextPercentageThreshold: 0.5,
-          },
         },
         mcpServers: {
           'server-1': {
@@ -2046,9 +2011,6 @@ describe('Settings Loading and Merging', () => {
           myTheme: {},
         },
         model: 'gemini-pro',
-        chatCompression: {
-          contextPercentageThreshold: 0.5,
-        },
         mcpServers: {
           'server-1': {
             command: 'node server.js',
@@ -2088,9 +2050,6 @@ describe('Settings Loading and Merging', () => {
         },
         model: {
           name: 'gemini-pro',
-          chatCompression: {
-            contextPercentageThreshold: 0.8,
-          },
         },
         context: {
           fileName: 'CONTEXT.md',
@@ -2130,9 +2089,6 @@ describe('Settings Loading and Merging', () => {
         theme: 'dark',
         usageStatisticsEnabled: false,
         model: 'gemini-pro',
-        chatCompression: {
-          contextPercentageThreshold: 0.8,
-        },
         contextFileName: 'CONTEXT.md',
         includeDirectories: ['/src'],
         sandbox: true,

packages/cli/src/config/settings.ts

@@ -64,7 +64,7 @@ const MIGRATION_MAP: Record<string, string> = {
   autoAccept: 'tools.autoAccept',
   autoConfigureMaxOldSpaceSize: 'advanced.autoConfigureMemory',
   bugCommand: 'advanced.bugCommand',
-  chatCompression: 'model.chatCompression',
+  chatCompression: 'model.compressionThreshold',
   checkpointing: 'general.checkpointing',
   coreTools: 'tools.core',
   contextFileName: 'context.fileName',

packages/cli/src/config/settingsSchema.ts

@@ -14,7 +14,6 @@ import type {
   BugCommandSettings,
   TelemetrySettings,
   AuthType,
-  ChatCompressionSettings,
 } from '@google/gemini-cli-core';
 import {
   DEFAULT_TRUNCATE_TOOL_OUTPUT_LINES,
@@ -578,14 +577,15 @@ const SETTINGS_SCHEMA = {
         description: 'Settings for summarizing tool output.',
         showInDialog: false,
       },
-      chatCompression: {
-        type: 'object',
-        label: 'Chat Compression',
+      compressionThreshold: {
+        type: 'number',
+        label: 'Compression Threshold',
         category: 'Model',
         requiresRestart: false,
-        default: undefined as ChatCompressionSettings | undefined,
-        description: 'Chat compression settings.',
-        showInDialog: false,
+        default: 0.2 as number,
+        description:
+          'The fraction of context usage at which to trigger context compression (e.g. 0.2, 0.3).',
+        showInDialog: true,
       },
       skipNextSpeakerCheck: {
         type: 'boolean',

packages/core/src/config/config.ts

@@ -92,10 +92,6 @@ export interface BugCommandSettings {
   urlTemplate: string;
 }
 
-export interface ChatCompressionSettings {
-  contextPercentageThreshold?: number;
-}
-
 export interface SummarizeToolOutputSettings {
   tokenBudget?: number;
 }
@@ -262,7 +258,7 @@ export interface ConfigParameters {
   folderTrust?: boolean;
   ideMode?: boolean;
   loadMemoryFromIncludeDirectories?: boolean;
-  chatCompression?: ChatCompressionSettings;
+  compressionThreshold?: number;
   interactive?: boolean;
   trustedFolder?: boolean;
   useRipgrep?: boolean;
@@ -359,7 +355,7 @@ export class Config {
     | undefined;
   private readonly experimentalZedIntegration: boolean = false;
   private readonly loadMemoryFromIncludeDirectories: boolean = false;
-  private readonly chatCompression: ChatCompressionSettings | undefined;
+  private readonly compressionThreshold: number | undefined;
   private readonly interactive: boolean;
   private readonly ptyInfo: string;
   private readonly trustedFolder: boolean | undefined;
@@ -462,7 +458,7 @@ export class Config {
     this.ideMode = params.ideMode ?? false;
     this.loadMemoryFromIncludeDirectories =
       params.loadMemoryFromIncludeDirectories ?? false;
-    this.chatCompression = params.chatCompression;
+    this.compressionThreshold = params.compressionThreshold;
     this.interactive = params.interactive ?? false;
     this.ptyInfo = params.ptyInfo ?? 'child_process';
     this.trustedFolder = params.trustedFolder;
@@ -1003,8 +999,8 @@ export class Config {
     this.fileSystemService = fileSystemService;
   }
 
-  getChatCompression(): ChatCompressionSettings | undefined {
-    return this.chatCompression;
+  getCompressionThreshold(): number | undefined {
+    return this.compressionThreshold;
   }
 
   isInteractiveShellEnabled(): boolean {

packages/core/src/services/chatCompressionService.test.ts

@@ -70,7 +70,7 @@ describe('findCompressSplitPoint', () => {
     expect(findCompressSplitPoint(history, 0.8)).toBe(4);
   });
 
-  it('should return earlier splitpoint if no valid ones are after threshhold', () => {
+  it('should return earlier splitpoint if no valid ones are after threshold', () => {
     const history: Content[] = [
       { role: 'user', parts: [{ text: 'This is the first message.' }] },
       { role: 'model', parts: [{ text: 'This is the second message.' }] },
@@ -115,7 +115,7 @@ describe('ChatCompressionService', () => {
       getLastPromptTokenCount: vi.fn().mockReturnValue(500),
     } as unknown as GeminiChat;
     mockConfig = {
-      getChatCompression: vi.fn(),
+      getCompressionThreshold: vi.fn(),
       getContentGenerator: vi.fn(),
     } as unknown as Config;
 

packages/core/src/services/chatCompressionService.ts

@@ -106,8 +106,7 @@ export class ChatCompressionService {
     // Don't compress if not forced and we are under the limit.
     if (!force) {
       const threshold =
-        config.getChatCompression()?.contextPercentageThreshold ??
-        DEFAULT_COMPRESSION_TOKEN_THRESHOLD;
+        config.getCompressionThreshold() ?? DEFAULT_COMPRESSION_TOKEN_THRESHOLD;
       if (originalTokenCount < threshold * tokenLimit(model)) {
         return {
           newHistory: null,