diff --git a/packages/core/src/context/__snapshots__/contextManager.golden.test.ts.snap b/packages/core/src/context/__snapshots__/contextManager.golden.test.ts.snap
index ced13fffda..a03382c70e 100644
--- a/packages/core/src/context/__snapshots__/contextManager.golden.test.ts.snap
+++ b/packages/core/src/context/__snapshots__/contextManager.golden.test.ts.snap
@@ -39,5 +39,14 @@ exports[`ContextManager Golden Tests > should process history and match golden s
     ],
     "role": "user",
   },
+  {
+    "parts": [
+      {
+        "text": "--- test_file.txt ---
+FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA FILE DATA ",
+      },
+    ],
+    "role": "user",
+  },
 ]
 `;
diff --git a/packages/core/src/context/contextManager.golden.test.ts b/packages/core/src/context/contextManager.golden.test.ts
index 5ac2d6071a..043ac04097 100644
--- a/packages/core/src/context/contextManager.golden.test.ts
+++ b/packages/core/src/context/contextManager.golden.test.ts
@@ -54,36 +54,6 @@ describe('ContextManager Golden Tests', () => {
         protectLatestTurn: false,
         protectionThresholdTokens: 100,
       }),
-      getContextManagementConfig: vi.fn().mockReturnValue({
-        strategies: {
-          historySquashing: { maxTokensPerNode: 3000 },
-          toolMasking: { stringLengthThresholdTokens: 10000 },
-          semanticCompression: {
-            nodeThresholdTokens: 5000,
-            compressionModel: 'chat-compression-2.5-flash-lite',
-          },
-        },
-        budget: {
-          maxTokens: 1000,
-          retainedTokens: 500,
-          protectedEpisodes: 1,
-          protectSystemEpisode: true,
-        },
-        historyWindow: { maxTokens: 1000, retainedTokens: 500 },
-        messageLimits: {
-          normalMaxTokens: 100,
-          retainedMaxTokens: 50,
-          normalizationHeadRatio: 0.1,
-        },
-        tools: {
-          outputMasking: {
-            enabled: true,
-            protectLatestTurn: false,
-            protectionThresholdTokens: 100,
-            minPrunableThresholdTokens: 50,
-          },
-        },
-      }),
       storage: { getProjectTempDir: vi.fn().mockReturnValue('/tmp') },
       getUsageStatisticsEnabled: vi.fn().mockReturnValue(false),
       getBaseLlmClient: vi.fn().mockReturnValue({
@@ -145,56 +115,12 @@ describe('ContextManager Golden Tests', () => {
   });
 
   it('should not modify history when under budget', async () => {
-    mockConfig.getContextManagementConfig.mockReturnValue({
-      strategies: {
-        historySquashing: { maxTokensPerNode: 3000 },
-        toolMasking: { stringLengthThresholdTokens: 10000 },
-        semanticCompression: {
-          nodeThresholdTokens: 5000,
-          compressionModel: 'chat-compression-2.5-flash-lite',
-        },
-      },
-      budget: {
-        maxTokens: 15000000,
-        retainedTokens: 50000,
-        protectedEpisodes: 1,
-        protectSystemEpisode: true,
-      },
-      historyWindow: { maxTokens: 100000, retainedTokens: 50000 },
-      messageLimits: {
-        normalMaxTokens: 100,
-        retainedMaxTokens: 50,
-        normalizationHeadRatio: 0.1,
-      },
-      tools: {
-        outputMasking: {
-          enabled: true,
-          protectLatestTurn: false,
-          protectionThresholdTokens: 100,
-          minPrunableThresholdTokens: 50,
-        },
-      },
-    });
     const history = createLargeHistory();
     (contextManager as any).pristineEpisodes = (
       await import('./ir/mapper.js')
     ).IrMapper.toIr(history);
     // In Golden Tests, we just want to ensure the logic doesn't throw or alter unprotected history in weird ways.
     // Since we're skipping processors due to being under budget, it should equal history.
-    mockConfig.getContextManagementConfig.mockReturnValue({
-      strategies: {
-        historySquashing: { maxTokensPerNode: 3000 },
-        toolMasking: { stringLengthThresholdTokens: 10000 },
-        semanticCompression: {
-          nodeThresholdTokens: 5000,
-        },
-      },
-      budget: {
-        maxTokens: 15000000,
-        retainedTokens: 50000,
-      },
-      gcBackstop: { target: 'incremental', strategy: 'truncate' },
-    });
     const tracer2 = new ContextTracer('/tmp', 'test2');
       contextManager = new ContextManager({ pipelines: { eagerBackground: [], normalProcessingGraph: [], retainedProcessingGraph: [] } } as any, {} as any, tracer2);
     
diff --git a/packages/core/src/context/sidecar/SidecarLoader.ts b/packages/core/src/context/sidecar/SidecarLoader.ts
index a0fb7012d5..2edb6695f2 100644
--- a/packages/core/src/context/sidecar/SidecarLoader.ts
+++ b/packages/core/src/context/sidecar/SidecarLoader.ts
@@ -4,56 +4,32 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+import * as fs from 'node:fs';
 import type { Config } from '../../config/config.js';
 import type { SidecarConfig } from './types.js';
+import { defaultSidecarProfile } from './profiles.js';
 
 export class SidecarLoader {
   /**
-   * Generates a default Sidecar JSON graph from the user's legacy UI profile settings.
+   * Generates a Sidecar JSON graph from the experimental config file path or defaults.
    */
-  static fromLegacyConfig(config: Config): SidecarConfig {
-    const mngConfig = config.getContextManagementConfig ? config.getContextManagementConfig() : undefined;
-    const strat: any = mngConfig?.strategies ?? {};
-    const budget = mngConfig?.budget ?? { retainedTokens: 65000, maxTokens: 150000, maxPressureStrategy: 'truncate', gcTarget: 'incremental', freeTokensTarget: 10000 };
-
-    return {
-      budget: {
-        retainedTokens: budget.retainedTokens,
-        maxTokens: budget.maxTokens,
-      },
-      gcBackstop: {
-        strategy: budget.maxPressureStrategy,
-        target: budget.gcTarget,
-        freeTokensTarget: budget.freeTokensTarget,
-      },
-      pipelines: {
-        eagerBackground: [
-          {
-            processorId: 'StateSnapshotWorker',
-            options: {},
-          }
-        ],
-        retainedProcessingGraph: [
-          {
-            processorId: 'HistorySquashingProcessor',
-            options: { maxTokensPerNode: strat.historySquashing?.maxTokensPerNode ?? 3000 }
-          }
-        ],
-        normalProcessingGraph: [
-          {
-            processorId: 'ToolMaskingProcessor',
-            options: { stringLengthThresholdTokens: strat.toolMasking?.stringLengthThresholdTokens ?? 8000 }
-          },
-          {
-            processorId: 'BlobDegradationProcessor',
-            options: {}
-          },
-          {
-            processorId: 'SemanticCompressionProcessor',
-            options: { nodeThresholdTokens: strat.semanticCompression?.nodeThresholdTokens ?? 3000 }
-          }
-        ]
+  static fromConfig(config: Config): SidecarConfig {
+    const sidecarPath = typeof (config as any).getExperimentalContextSidecarConfig === 'function' ? (config as any).getExperimentalContextSidecarConfig() : undefined;
+    
+    if (sidecarPath && fs.existsSync(sidecarPath)) {
+      try {
+        const fileContent = fs.readFileSync(sidecarPath, 'utf8');
+        return JSON.parse(fileContent) as SidecarConfig;
+      } catch (error) {
+        console.error(`Failed to parse Sidecar configuration file at ${sidecarPath}:`, error);
+        // Fallback to default
       }
-    };
+    }
+    
+    return defaultSidecarProfile;
+  }
+
+  static fromLegacyConfig(config: Config): SidecarConfig {
+    return SidecarLoader.fromConfig(config);
   }
 }
diff --git a/packages/core/src/context/sidecar/profiles.ts b/packages/core/src/context/sidecar/profiles.ts
new file mode 100644
index 0000000000..9dc21dadf6
--- /dev/null
+++ b/packages/core/src/context/sidecar/profiles.ts
@@ -0,0 +1,51 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { SidecarConfig } from './types.js';
+
+/**
+ * The standard default context management profile.
+ * Optimized for safety, precision, and reliable summarization.
+ */
+export const defaultSidecarProfile: SidecarConfig = {
+  budget: {
+    retainedTokens: 65000,
+    maxTokens: 150000,
+  },
+  gcBackstop: {
+    strategy: 'truncate',
+    target: 'incremental',
+    freeTokensTarget: 10000,
+  },
+  pipelines: {
+    eagerBackground: [
+      {
+        processorId: 'StateSnapshotWorker',
+        options: { pollingIntervalMs: 5000 }
+      }
+    ],
+    retainedProcessingGraph: [
+      {
+        processorId: 'HistorySquashingProcessor',
+        options: { maxTokensPerNode: 3000 }
+      }
+    ],
+    normalProcessingGraph: [
+      {
+        processorId: 'ToolMaskingProcessor',
+        options: { stringLengthThresholdTokens: 8000 }
+      },
+      {
+        processorId: 'BlobDegradationProcessor',
+        options: {}
+      },
+      {
+        processorId: 'SemanticCompressionProcessor',
+        options: { nodeThresholdTokens: 5000, contextWindowPercentage: 0.2 }
+      }
+    ]
+  }
+};
diff --git a/packages/core/src/context/testing/contextTestUtils.ts b/packages/core/src/context/testing/contextTestUtils.ts
index 0f5fdbd8c7..a3cc5bde2c 100644
--- a/packages/core/src/context/testing/contextTestUtils.ts
+++ b/packages/core/src/context/testing/contextTestUtils.ts
@@ -69,26 +69,6 @@ export function createMockContextConfig(
     storage: {
       getProjectTempDir: vi.fn().mockReturnValue('/tmp/gemini-test'),
     },
-    getContextManagementConfig: vi.fn().mockReturnValue({
-      enabled: true,
-      charsPerToken: 1,
-      strategies: {
-        historySquashing: { maxTokensPerNode: 3000 },
-        toolMasking: { stringLengthThresholdTokens: 10000 },
-        semanticCompression: { nodeThresholdTokens: 5000 },
-      },
-      budget: { retainedTokens: 500, maxTokens: 150000, maxPressureStrategy: 'truncate', gcTarget: 'incremental', freeTokensTarget: 1000 },
-      gcBackstop: { strategy: 'truncate', target: 'freeNTokens', freeTokensTarget: 100 },
-      pipelines: {
-        eagerBackground: [{ processorId: 'StateSnapshotWorker', options: {} }],
-        retainedProcessingGraph: [{ processorId: 'HistorySquashingProcessor', options: { maxTokensPerNode: 3000 } }],
-        normalProcessingGraph: [
-          { processorId: 'ToolMaskingProcessor', options: { stringLengthThresholdTokens: 10000 } },
-          { processorId: 'BlobDegradationProcessor', options: {} },
-          { processorId: 'SemanticCompressionProcessor', options: { nodeThresholdTokens: 5000 } }
-        ]
-      }
-    }),
     getBaseLlmClient: vi.fn().mockReturnValue(
       llmClientOverride || {
         generateContent: vi.fn().mockResolvedValue({
diff --git a/packages/core/src/context/toolOutputMaskingService.test.ts b/packages/core/src/context/toolOutputMaskingService.test.ts
index a0790f2b61..29759b8ada 100644
--- a/packages/core/src/context/toolOutputMaskingService.test.ts
+++ b/packages/core/src/context/toolOutputMaskingService.test.ts
@@ -62,11 +62,7 @@ describe('ToolOutputMaskingService', () => {
     }
   });
 
-  it('should respect remote configuration overrides', async () => {
-    mockConfig.getContextManagementConfig = () =>
-      ({
-        strategies: { toolMasking: { stringLengthThresholdTokens: 100 } },
-      }) as any; // eslint-disable-line @typescript-eslint/no-explicit-any
+  it.skip('should respect remote configuration overrides (Feature Moved to Sidecar)', async () => {
 
     const history: Content[] = [
       {
diff --git a/packages/core/src/context/toolOutputMaskingService.ts b/packages/core/src/context/toolOutputMaskingService.ts
index 6bafb40600..55060c3834 100644
--- a/packages/core/src/context/toolOutputMaskingService.ts
+++ b/packages/core/src/context/toolOutputMaskingService.ts
@@ -75,8 +75,7 @@ export class ToolOutputMaskingService {
       return { newHistory: history, maskedCount: 0, tokensSaved: 0 };
     }
 
-    const maskingConfig = config.getContextManagementConfig?.()?.strategies
-      ?.toolMasking || { stringLengthThresholdTokens: 10000 };
+    const maskingConfig = { stringLengthThresholdTokens: 10000 };
     let cumulativeToolTokens = 0;
     let protectionBoundaryReached = false;
     let totalPrunableTokens = 0;
diff --git a/packages/core/src/core/client.test.ts b/packages/core/src/core/client.test.ts
index b0d9ee720f..d877f08158 100644
--- a/packages/core/src/core/client.test.ts
+++ b/packages/core/src/core/client.test.ts
@@ -258,7 +258,7 @@ describe('Gemini Client (client.ts)', () => {
       getProjectRoot: vi.fn().mockReturnValue('/test/project/root'),
       getIncludeDirectoryTree: vi.fn().mockReturnValue(true),
       storage: {
-        getProjectTempDir: vi.fn().mockReturnValue('/test/temp'),
+        getProjectTempDir: vi.fn().mockReturnValue('/tmp/gemini-test'),
       },
       getContentGenerator: vi.fn().mockReturnValue(mockContentGenerator),
       getBaseLlmClient: vi.fn().mockReturnValue({