Add a context percentage threshold setting for auto compression (#5721)

4 files changed, 179 insertions, 0 deletions

diff --git a/packages/cli/src/config/config.test.ts b/packages/cli/src/config/config.test.ts
index 6a7e3b57..b670fbc8 100644
--- a/packages/cli/src/config/config.test.ts
+++ b/packages/cli/src/config/config.test.ts
@@ -1123,3 +1123,42 @@ describe('loadCliConfig with includeDirectories', () => {
     );
   });
 });
+
+describe('loadCliConfig chatCompression', () => {
+  const originalArgv = process.argv;
+  const originalEnv = { ...process.env };
+
+  beforeEach(() => {
+    vi.resetAllMocks();
+    vi.mocked(os.homedir).mockReturnValue('/mock/home/user');
+    process.env.GEMINI_API_KEY = 'test-api-key';
+  });
+
+  afterEach(() => {
+    process.argv = originalArgv;
+    process.env = originalEnv;
+    vi.restoreAllMocks();
+  });
+
+  it('should pass chatCompression settings to the core config', async () => {
+    process.argv = ['node', 'script.js'];
+    const argv = await parseArguments();
+    const settings: Settings = {
+      chatCompression: {
+        contextPercentageThreshold: 0.5,
+      },
+    };
+    const config = await loadCliConfig(settings, [], 'test-session', argv);
+    expect(config.getChatCompression()).toEqual({
+      contextPercentageThreshold: 0.5,
+    });
+  });
+
+  it('should have undefined chatCompression if not in settings', async () => {
+    process.argv = ['node', 'script.js'];
+    const argv = await parseArguments();
+    const settings: Settings = {};
+    const config = await loadCliConfig(settings, [], 'test-session', argv);
+    expect(config.getChatCompression()).toBeUndefined();
+  });
+});
diff --git a/packages/cli/src/config/config.ts b/packages/cli/src/config/config.ts
index 2c942c08..a47d8301 100644
--- a/packages/cli/src/config/config.ts
+++ b/packages/cli/src/config/config.ts
@@ -482,6 +482,7 @@ export async function loadCliConfig(
     summarizeToolOutput: settings.summarizeToolOutput,
     ideMode,
     ideModeFeature,
+    chatCompression: settings.chatCompression,
     folderTrustFeature,
   });
 }
diff --git a/packages/cli/src/config/settings.test.ts b/packages/cli/src/config/settings.test.ts
index d0266720..f68b13e3 100644
--- a/packages/cli/src/config/settings.test.ts
+++ b/packages/cli/src/config/settings.test.ts
@@ -113,6 +113,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
       expect(settings.errors.length).toBe(0);
     });
@@ -147,6 +148,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
     });
 
@@ -181,6 +183,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
     });
 
@@ -213,6 +216,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
     });
 
@@ -251,6 +255,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
     });
 
@@ -301,6 +306,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
     });
 
@@ -622,6 +628,116 @@ describe('Settings Loading and Merging', () => {
       expect(settings.merged.mcpServers).toEqual({});
     });
 
+    it('should merge chatCompression settings, with workspace taking precedence', () => {
+      (mockFsExistsSync as Mock).mockReturnValue(true);
+      const userSettingsContent = {
+        chatCompression: { contextPercentageThreshold: 0.5 },
+      };
+      const workspaceSettingsContent = {
+        chatCompression: { contextPercentageThreshold: 0.8 },
+      };
+
+      (fs.readFileSync as Mock).mockImplementation(
+        (p: fs.PathOrFileDescriptor) => {
+          if (p === USER_SETTINGS_PATH)
+            return JSON.stringify(userSettingsContent);
+          if (p === MOCK_WORKSPACE_SETTINGS_PATH)
+            return JSON.stringify(workspaceSettingsContent);
+          return '{}';
+        },
+      );
+
+      const settings = loadSettings(MOCK_WORKSPACE_DIR);
+
+      expect(settings.user.settings.chatCompression).toEqual({
+        contextPercentageThreshold: 0.5,
+      });
+      expect(settings.workspace.settings.chatCompression).toEqual({
+        contextPercentageThreshold: 0.8,
+      });
+      expect(settings.merged.chatCompression).toEqual({
+        contextPercentageThreshold: 0.8,
+      });
+    });
+
+    it('should handle chatCompression when only in user settings', () => {
+      (mockFsExistsSync as Mock).mockImplementation(
+        (p: fs.PathLike) => p === USER_SETTINGS_PATH,
+      );
+      const userSettingsContent = {
+        chatCompression: { contextPercentageThreshold: 0.5 },
+      };
+      (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.chatCompression).toEqual({
+        contextPercentageThreshold: 0.5,
+      });
+    });
+
+    it('should have chatCompression as an empty object if not in any settings file', () => {
+      (mockFsExistsSync as Mock).mockReturnValue(false); // No settings files exist
+      (fs.readFileSync as Mock).mockReturnValue('{}');
+      const settings = loadSettings(MOCK_WORKSPACE_DIR);
+      expect(settings.merged.chatCompression).toEqual({});
+    });
+
+    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 = {
+        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.chatCompression).toBeUndefined();
+      expect(warnSpy).toHaveBeenCalledWith(
+        'Invalid value for chatCompression.contextPercentageThreshold: "1.5". Please use a value between 0 and 1. Using default compression settings.',
+      );
+      warnSpy.mockRestore();
+    });
+
+    it('should deep merge chatCompression settings', () => {
+      (mockFsExistsSync as Mock).mockReturnValue(true);
+      const userSettingsContent = {
+        chatCompression: { contextPercentageThreshold: 0.5 },
+      };
+      const workspaceSettingsContent = {
+        chatCompression: {},
+      };
+
+      (fs.readFileSync as Mock).mockImplementation(
+        (p: fs.PathOrFileDescriptor) => {
+          if (p === USER_SETTINGS_PATH)
+            return JSON.stringify(userSettingsContent);
+          if (p === MOCK_WORKSPACE_SETTINGS_PATH)
+            return JSON.stringify(workspaceSettingsContent);
+          return '{}';
+        },
+      );
+
+      const settings = loadSettings(MOCK_WORKSPACE_DIR);
+
+      expect(settings.merged.chatCompression).toEqual({
+        contextPercentageThreshold: 0.5,
+      });
+    });
+
     it('should merge includeDirectories from all scopes', () => {
       (mockFsExistsSync as Mock).mockReturnValue(true);
       const systemSettingsContent = {
@@ -695,6 +811,7 @@ describe('Settings Loading and Merging', () => {
         customThemes: {},
         mcpServers: {},
         includeDirectories: [],
+        chatCompression: {},
       });
 
       // Check that error objects are populated in settings.errors
@@ -1132,6 +1249,7 @@ describe('Settings Loading and Merging', () => {
           customThemes: {},
           mcpServers: {},
           includeDirectories: [],
+          chatCompression: {},
         });
       });
     });
diff --git a/packages/cli/src/config/settings.ts b/packages/cli/src/config/settings.ts
index 64500845..8005ad65 100644
--- a/packages/cli/src/config/settings.ts
+++ b/packages/cli/src/config/settings.ts
@@ -13,6 +13,7 @@ import {
   GEMINI_CONFIG_DIR as GEMINI_DIR,
   getErrorMessage,
   BugCommandSettings,
+  ChatCompressionSettings,
   TelemetrySettings,
   AuthType,
 } from '@google/gemini-cli-core';
@@ -134,6 +135,8 @@ export interface Settings {
   includeDirectories?: string[];
 
   loadMemoryFromIncludeDirectories?: boolean;
+
+  chatCompression?: ChatCompressionSettings;
 }
 
 export interface SettingsError {
@@ -194,6 +197,11 @@ export class LoadedSettings {
         ...(user.includeDirectories || []),
         ...(workspace.includeDirectories || []),
       ],
+      chatCompression: {
+        ...(system.chatCompression || {}),
+        ...(user.chatCompression || {}),
+        ...(workspace.chatCompression || {}),
+      },
     };
   }
 
@@ -482,6 +490,19 @@ export function loadSettings(workspaceDir: string): LoadedSettings {
     settingsErrors,
   );
 
+  // Validate chatCompression settings
+  const chatCompression = loadedSettings.merged.chatCompression;
+  const threshold = chatCompression?.contextPercentageThreshold;
+  if (
+    threshold != null &&
+    (typeof threshold !== 'number' || threshold < 0 || threshold > 1)
+  ) {
+    console.warn(
+      `Invalid value for chatCompression.contextPercentageThreshold: "${threshold}". Please use a value between 0 and 1. Using default compression settings.`,
+    );
+    delete loadedSettings.merged.chatCompression;
+  }
+
   // Load environment with merged settings
   loadEnvironment(loadedSettings.merged);