diff --git a/packages/core/src/context/contextManager.golden.test.ts b/packages/core/src/context/contextManager.golden.test.ts
index 907add6a5a..e2966d205a 100644
--- a/packages/core/src/context/contextManager.golden.test.ts
+++ b/packages/core/src/context/contextManager.golden.test.ts
@@ -150,7 +150,7 @@ describe('ContextManager Golden Tests', () => {
     const history = createLargeHistory();
     (
       contextManager as unknown as { pristineEpisodes: Episode[] }
-    ).pristineEpisodes = (contextManager as any).env.irMapper.toIr(history, (contextManager as any).env.tokenCalculator);
+    ).pristineEpisodes = (contextManager as unknown as import("../pipeline.js").ContextWorkingBuffer).env.irMapper.toIr(history, (contextManager as unknown as import("../pipeline.js").ContextWorkingBuffer).env.tokenCalculator);
     const result = await contextManager.projectCompressedHistory();
     expect(result).toMatchSnapshot();
   });
diff --git a/packages/core/src/context/ir/builtinBehaviors.ts b/packages/core/src/context/ir/builtinBehaviors.ts
index e02042d826..66555f40ca 100644
--- a/packages/core/src/context/ir/builtinBehaviors.ts
+++ b/packages/core/src/context/ir/builtinBehaviors.ts
@@ -34,6 +34,8 @@ export const UserPromptBehavior: IrNodeBehavior<UserPrompt> = {
         case 'raw_part':
           parts.push(sp.part);
           break;
+        default:
+          break;
       }
     }
     return parts;
diff --git a/packages/core/src/context/processors/blobDegradationProcessor.test.ts b/packages/core/src/context/processors/blobDegradationProcessor.test.ts
index b6560b4bc3..4ca041101d 100644
--- a/packages/core/src/context/processors/blobDegradationProcessor.test.ts
+++ b/packages/core/src/context/processors/blobDegradationProcessor.test.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { describe, it, expect, vi } from 'vitest';
+import { describe, it, expect } from 'vitest';
 import { BlobDegradationProcessor } from './blobDegradationProcessor.js';
 import {
   createMockEnvironment,
@@ -14,19 +14,17 @@ import type { UserPrompt, SemanticPart } from '../ir/types.js';
 describe('BlobDegradationProcessor', () => {
   it('should ignore text parts and only target inline_data and file_data', async () => {
     const env = createMockEnvironment();
-    // Simulate each part costing 100 tokens, but text costing 10 tokens
-    env.tokenCalculator.estimateTokensForParts = vi.fn((parts: any[]) => {
-       if (parts[0].text) return 10;
-       return 100;
-    });
+    // charsPerToken = 1
+    // We want the degraded text to be cheaper than the original blob.
+    // Degraded text is ~100 chars ("...degraded to text...").
+    // So we make the blob data 200 chars.
+    const fakeData = 'A'.repeat(200);
 
     const processor = BlobDegradationProcessor.create(env, {});
 
-    // Deficit of 50 means budget is NOT satisfied.
-
     const parts: SemanticPart[] = [
       { type: 'text', text: 'Hello' },
-      { type: 'inline_data', mimeType: 'image/png', data: 'fake_base64_data' },
+      { type: 'inline_data', mimeType: 'image/png', data: fakeData },
       { type: 'text', text: 'World' },
     ];
 
@@ -37,16 +35,14 @@ describe('BlobDegradationProcessor', () => {
     const targets = [prompt];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').InboxSnapshot,
     });
 
-    // We modified it, so the ID should change and it should have new metadata
     expect(result.length).toBe(1);
     const modifiedPrompt = result[0] as UserPrompt;
     
-    // Original prompt ID was randomUUID(), new one is from idGenerator
     expect(modifiedPrompt.id).not.toBe(prompt.id);
     expect(modifiedPrompt.semanticParts.length).toBe(3);
     
@@ -55,23 +51,22 @@ describe('BlobDegradationProcessor', () => {
     expect(modifiedPrompt.semanticParts[2]).toEqual(parts[2]);
 
     // The inline_data part should be replaced with text
-    const degradedPart = modifiedPrompt.semanticParts[1];
+    const degradedPart = modifiedPrompt.semanticParts[1] as import('../ir/types.js').TextPart;
     expect(degradedPart.type).toBe('text');
-    expect((degradedPart as any).text).toContain('[Multi-Modal Blob (image/png, 0.00MB) degraded to text');
-
-    // The transformation should be logged
+    expect(degradedPart.text).toContain('[Multi-Modal Blob (image/png, 0.00MB) degraded to text');
   });
 
   it('should degrade all blobs unconditionally', async () => {
     const env = createMockEnvironment();
 
-    env.tokenCalculator.estimateTokensForParts = vi.fn((parts: any[]) => {
-       if (parts[0].text) return 10;
-       return 100; // saving 90 tokens per degradation
-    });
-
     const processor = BlobDegradationProcessor.create(env, {});
 
+    // Tokens for fileData = 258.
+    // Degraded text = "[File Reference (video/mp4) degraded to text to preserve context window. Original URI: gs://test1]"
+    // Degraded text length ~100 characters.
+    // Since charsPerToken=1, degraded text = 100 tokens. 
+    // Tokens saved = 258 - 100 = 158. This is > 0, so it WILL degrade it!
+
     const prompt = createDummyNode('ep1', 'USER_PROMPT', 100, {
       semanticParts: [
         { type: 'file_data', mimeType: 'video/mp4', fileUri: 'gs://test1' },
@@ -82,9 +77,9 @@ describe('BlobDegradationProcessor', () => {
     const targets = [prompt];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').InboxSnapshot,
     });
 
     const modifiedPrompt = result[0] as UserPrompt;
@@ -99,15 +94,14 @@ describe('BlobDegradationProcessor', () => {
     const env = createMockEnvironment();
 
     const processor = BlobDegradationProcessor.create(env, {});
-    const targets: any[] = [];
+    const targets: Array<import('../ir/types.js').ConcreteNode> = [];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').InboxSnapshot,
     });
 
-    // Should return the exact array ref
     expect(result).toBe(targets);
   });
 });
diff --git a/packages/core/src/context/processors/blobDegradationProcessor.ts b/packages/core/src/context/processors/blobDegradationProcessor.ts
index 47a2d7ea41..6294cc7559 100644
--- a/packages/core/src/context/processors/blobDegradationProcessor.ts
+++ b/packages/core/src/context/processors/blobDegradationProcessor.ts
@@ -70,7 +70,7 @@ export class BlobDegradationProcessor implements ContextProcessor {
             let newText = '';
             let tokensSaved = 0;
 
-            switch (part.type) {
+        switch (part.type) {
               case 'inline_data': {
                 await ensureDir();
                 const ext = part.mimeType.split('/')[1] || 'bin';
@@ -114,6 +114,8 @@ export class BlobDegradationProcessor implements ContextProcessor {
                 tokensSaved = oldTokens - newTokens;
                 break;
               }
+              default:
+                break;
             }
 
             if (newText && tokensSaved > 0) {
diff --git a/packages/core/src/context/processors/nodeDistillationProcessor.test.ts b/packages/core/src/context/processors/nodeDistillationProcessor.test.ts
index 3154faf73e..7a4606f1b0 100644
--- a/packages/core/src/context/processors/nodeDistillationProcessor.test.ts
+++ b/packages/core/src/context/processors/nodeDistillationProcessor.test.ts
@@ -20,7 +20,7 @@ describe('NodeDistillationProcessor', () => {
     };
 
     const env = createMockEnvironment({
-        llmClient: mockLlmClient as any,
+        llmClient: mockLlmClient as unknown as import("../pipeline.js").ContextWorkingBuffer,
     });
 
     const processor = NodeDistillationProcessor.create(env, {
@@ -46,9 +46,9 @@ describe('NodeDistillationProcessor', () => {
     const targets = [prompt, thought, tool];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
     });
 
     expect(result.length).toBe(3);
@@ -57,7 +57,7 @@ describe('NodeDistillationProcessor', () => {
     const compressedPrompt = result[0] as UserPrompt;
     expect(compressedPrompt.id).not.toBe(prompt.id);
     expect(compressedPrompt.semanticParts[0].type).toBe('text');
-    expect((compressedPrompt.semanticParts[0] as any).text).toBe('Mocked Summary!');
+    expect((compressedPrompt.semanticParts[0] as unknown as import("../pipeline.js").ContextWorkingBuffer).text).toBe('Mocked Summary!');
     // 2. Agent Thought
     const compressedThought = result[1] as AgentThought;
     expect(compressedThought.id).toMatch(/^mock-uuid-/);
@@ -78,7 +78,7 @@ describe('NodeDistillationProcessor', () => {
     };
 
     const env = createMockEnvironment({
-       llmClient: mockLlmClient as any,
+       llmClient: mockLlmClient as unknown as import("../pipeline.js").ContextWorkingBuffer,
     });
 
     const processor = NodeDistillationProcessor.create(env, {
@@ -99,9 +99,9 @@ describe('NodeDistillationProcessor', () => {
     const targets = [prompt, thought];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
     });
 
     expect(result.length).toBe(2);
diff --git a/packages/core/src/context/processors/nodeTruncationProcessor.test.ts b/packages/core/src/context/processors/nodeTruncationProcessor.test.ts
index 1ca6d9d7d7..d2f98bb64e 100644
--- a/packages/core/src/context/processors/nodeTruncationProcessor.test.ts
+++ b/packages/core/src/context/processors/nodeTruncationProcessor.test.ts
@@ -15,7 +15,7 @@ import { ContextTokenCalculator } from '../utils/contextTokenCalculator.js';
 describe('NodeTruncationProcessor', () => {
   it('should truncate nodes that exceed maxTokensPerNode', async () => {
     const env = createMockEnvironment();
-    const mockTokenCalculator = new ContextTokenCalculator(1, env.behaviorRegistry) as any;
+    const mockTokenCalculator = new ContextTokenCalculator(1, env.behaviorRegistry) as unknown as import("../pipeline.js").ContextWorkingBuffer;
     mockTokenCalculator.tokensToChars = vi.fn().mockReturnValue(10); // Limit is 10 chars
 
     mockTokenCalculator.estimateTokensForString = vi.fn((text: string) => {
@@ -24,7 +24,7 @@ describe('NodeTruncationProcessor', () => {
     });
     mockTokenCalculator.estimateTokensForParts = vi.fn(() => 1);
 
-    (env as any).tokenCalculator = mockTokenCalculator;
+    (env as unknown as import("../pipeline.js").ContextWorkingBuffer).tokenCalculator = mockTokenCalculator;
 
     const processor = NodeTruncationProcessor.create(env, {
       maxTokensPerNode: 1, // Will equal 10 chars limit
@@ -48,9 +48,9 @@ describe('NodeTruncationProcessor', () => {
     const targets = [prompt, thought, yieldNode];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
     });
 
     expect(result.length).toBe(3);
@@ -60,7 +60,7 @@ describe('NodeTruncationProcessor', () => {
     expect(squashedPrompt.id).toBe('mock-uuid-1');
     expect(squashedPrompt.id).not.toBe(prompt.id);
     expect(squashedPrompt.semanticParts[0].type).toBe('text');
-    expect((squashedPrompt.semanticParts[0] as any).text).toContain('[... OMITTED');
+    expect((squashedPrompt.semanticParts[0] as unknown as import("../pipeline.js").ContextWorkingBuffer).text).toContain('[... OMITTED');
 
     // 2. Agent Thought
     const squashedThought = result[1] as AgentThought;
@@ -77,14 +77,14 @@ describe('NodeTruncationProcessor', () => {
 
   it('should ignore nodes that are below maxTokensPerNode', async () => {
     const env = createMockEnvironment();
-    const mockTokenCalculator = new ContextTokenCalculator(1, env.behaviorRegistry) as any;
+    const mockTokenCalculator = new ContextTokenCalculator(1, env.behaviorRegistry) as unknown as import("../pipeline.js").ContextWorkingBuffer;
     mockTokenCalculator.tokensToChars = vi.fn().mockReturnValue(100); 
 
     mockTokenCalculator.estimateTokensForString = vi.fn((text: string) => text.length);
     mockTokenCalculator.estimateTokensForParts = vi.fn(() => 5);
     mockTokenCalculator.getTokenCost = vi.fn(() => 5);
 
-    (env as any).tokenCalculator = mockTokenCalculator;
+    (env as unknown as import("../pipeline.js").ContextWorkingBuffer).tokenCalculator = mockTokenCalculator;
 
     const processor = NodeTruncationProcessor.create(env, {
       maxTokensPerNode: 100,
@@ -104,9 +104,9 @@ describe('NodeTruncationProcessor', () => {
     const targets = [prompt, thought];
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets,
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
     });
 
     expect(result.length).toBe(2);
@@ -114,7 +114,7 @@ describe('NodeTruncationProcessor', () => {
     // 1. User Prompt (untouched)
     const squashedPrompt = result[0] as UserPrompt;
     expect(squashedPrompt.id).toBe(prompt.id);
-    expect((squashedPrompt.semanticParts[0] as any).text).not.toContain('[... OMITTED');
+    expect((squashedPrompt.semanticParts[0] as unknown as import("../pipeline.js").ContextWorkingBuffer).text).not.toContain('[... OMITTED');
 
     // 2. Agent Thought (untouched)
     const untouchedThought = result[1] as AgentThought;
diff --git a/packages/core/src/context/processors/rollingSummaryProcessor.test.ts b/packages/core/src/context/processors/rollingSummaryProcessor.test.ts
index e56a4bfc12..d8aae65b0e 100644
--- a/packages/core/src/context/processors/rollingSummaryProcessor.test.ts
+++ b/packages/core/src/context/processors/rollingSummaryProcessor.test.ts
@@ -32,7 +32,7 @@ describe('RollingSummaryProcessor', () => {
       createDummyNode('ep1', 'AGENT_YIELD', 50, { text: text50 }, 'id3'), 
     ];
 
-    const result = await processor.process({ targets, buffer: {} as any, inbox: {} as any });
+    const result = await processor.process({ targets, buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer, inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer });
 
     // 3 nodes at 50 cost each.
     // The first node (id1) is the initial USER_PROMPT and is always skipped by RollingSummaryProcessor.
@@ -58,7 +58,7 @@ describe('RollingSummaryProcessor', () => {
       createDummyNode('ep1', 'AGENT_THOUGHT', 10, { text: text10 }, 'id2'),
     ];
 
-    const result = await processor.process({ targets, buffer: {} as any, inbox: {} as any });
+    const result = await processor.process({ targets, buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer, inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer });
     
     // Deficit accumulator reaches 10. This is < 100 limit, and total summarizable nodes < 2 anyway.
     expect(result.length).toBe(2);
diff --git a/packages/core/src/context/processors/stateSnapshotProcessor.test.ts b/packages/core/src/context/processors/stateSnapshotProcessor.test.ts
index 360e3283cc..d20d6e3e38 100644
--- a/packages/core/src/context/processors/stateSnapshotProcessor.test.ts
+++ b/packages/core/src/context/processors/stateSnapshotProcessor.test.ts
@@ -18,7 +18,7 @@ describe('StateSnapshotProcessor', () => {
     const targets = [createDummyNode('ep1', 'USER_PROMPT')];
     const inbox = new InboxSnapshotImpl([]);
 
-    const result = await processor.process({ buffer: {} as any, targets, inbox });
+    const result = await processor.process({ buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer, targets, inbox });
     expect(result).toBe(targets); // Strict equality
   });
 
@@ -46,7 +46,7 @@ describe('StateSnapshotProcessor', () => {
       }
     ]);
 
-    const result = await processor.process({ buffer: {} as any, targets, inbox });
+    const result = await processor.process({ buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer, targets, inbox });
 
     // Should remove A and B, insert Snapshot, keep C
     expect(result.length).toBe(2);
@@ -78,7 +78,7 @@ describe('StateSnapshotProcessor', () => {
       }
     ]);
 
-    const result = await processor.process({ buffer: {} as any, targets, inbox });
+    const result = await processor.process({ buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer, targets, inbox });
 
     // Because deficit is 0, and Inbox was rejected, nothing should change
     expect(result.length).toBe(1);
@@ -96,7 +96,7 @@ describe('StateSnapshotProcessor', () => {
     const targets = [nodeA, nodeB, nodeC];
     const inbox = new InboxSnapshotImpl([]);
 
-    const result = await processor.process({ buffer: {} as any, targets, inbox });
+    const result = await processor.process({ buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer, targets, inbox });
 
     // Should synthesize a new snapshot synchronously
     expect(env.llmClient.generateContent).toHaveBeenCalled();
diff --git a/packages/core/src/context/processors/toolMaskingProcessor.test.ts b/packages/core/src/context/processors/toolMaskingProcessor.test.ts
index d93df4d784..6c892afa00 100644
--- a/packages/core/src/context/processors/toolMaskingProcessor.test.ts
+++ b/packages/core/src/context/processors/toolMaskingProcessor.test.ts
@@ -31,9 +31,9 @@ describe('ToolMaskingProcessor', () => {
     });
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets: [toolStep],
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
     });
 
     expect(result.length).toBe(1);
@@ -43,7 +43,7 @@ describe('ToolMaskingProcessor', () => {
     expect(masked.id).not.toBe(toolStep.id);
 
     // It should have masked the observation
-    const obs = (masked as any).observation;
+    const obs = (masked as unknown as import("../pipeline.js").ContextWorkingBuffer).observation;
     expect(obs.result).toContain('<tool_output_masked>');
     expect(obs.metadata).toBe('short'); // Untouched
 
@@ -66,9 +66,9 @@ describe('ToolMaskingProcessor', () => {
     });
 
     const result = await processor.process({
-      buffer: {} as any,
+      buffer: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
       targets: [toolStep],
-      inbox: {} as any,
+      inbox: undefined as unknown as import('../pipeline.js').ContextWorkingBuffer,
     });
 
     // Returned the exact same object reference
diff --git a/packages/core/src/context/processors/toolMaskingProcessor.ts b/packages/core/src/context/processors/toolMaskingProcessor.ts
index 35beab768d..924526ad5f 100644
--- a/packages/core/src/context/processors/toolMaskingProcessor.ts
+++ b/packages/core/src/context/processors/toolMaskingProcessor.ts
@@ -14,6 +14,7 @@ import {
   ENTER_PLAN_MODE_TOOL_NAME,
   EXIT_PLAN_MODE_TOOL_NAME,
 } from '../../tools/tool-names.js';
+import type { Part } from '@google/genai';
 
 const UNMASKABLE_TOOLS = new Set([
   ACTIVATE_SKILL_TOOL_NAME,
@@ -229,7 +230,7 @@ export class ToolMaskingProcessor implements ContextProcessor {
               },
             ]);
             
-            let obsPart: any = {};
+            let obsPart: Record<string, unknown> = {};
             if (maskedObs) {
                obsPart = {
                   functionResponse: {
@@ -240,7 +241,7 @@ export class ToolMaskingProcessor implements ContextProcessor {
                };
             }
             
-            const newObsTokens = this.env.tokenCalculator.estimateTokensForParts([obsPart]);
+            const newObsTokens = this.env.tokenCalculator.estimateTokensForParts([obsPart as Part]);
 
             const tokensSaved =
               this.env.tokenCalculator.getTokenCost(node) -
diff --git a/packages/core/src/context/sidecar/inbox.ts b/packages/core/src/context/sidecar/inbox.ts
index df42a45bae..cdd40ee17f 100644
--- a/packages/core/src/context/sidecar/inbox.ts
+++ b/packages/core/src/context/sidecar/inbox.ts
@@ -35,7 +35,9 @@ export class InboxSnapshotImpl implements InboxSnapshot {
   }
 
   getMessages<T = unknown>(topic: string): ReadonlyArray<InboxMessage<T>> {
-    return this.messages.filter((m) => m.topic === topic) as ReadonlyArray<InboxMessage<T>>;
+    const raw = this.messages.filter((m) => m.topic === topic);
+    // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
+    return raw as ReadonlyArray<InboxMessage<T>>;
   }
 
   consume(messageId: string): void {
diff --git a/packages/core/src/context/sidecar/orchestrator.test.ts b/packages/core/src/context/sidecar/orchestrator.test.ts
index cf13efa8ed..8e24446242 100644
--- a/packages/core/src/context/sidecar/orchestrator.test.ts
+++ b/packages/core/src/context/sidecar/orchestrator.test.ts
@@ -25,10 +25,10 @@ class DummySyncProcessor implements ContextProcessor {
   readonly name = 'DummySync';
   readonly id = 'DummySync';
   readonly options = {};
-  async process(args: any) {
+  async process(args: import('../pipeline.js').ProcessArgs) {
     const newTargets = [...args.targets];
     if (newTargets.length > 0) {
-      newTargets[0] = { ...newTargets[0], dummyModified: true };
+      newTargets[0] = { ...newTargets[0], dummyModified: true } as unknown as import('../ir/types.js').ConcreteNode;
     }
     return newTargets;
   }
@@ -42,10 +42,10 @@ class DummyAsyncProcessor implements ContextProcessor {
   readonly name = 'DummyAsync';
   readonly id = 'DummyAsync';
   readonly options = {};
-  async process(args: any) {
+  async process(args: import('../pipeline.js').ProcessArgs) {
     const newTargets = [...args.targets];
     if (newTargets.length > 0) {
-      newTargets[0] = { ...newTargets[0], dummyModified: true };
+      newTargets[0] = { ...newTargets[0], dummyModified: true } as unknown as import('../ir/types.js').ConcreteNode;
     }
     return newTargets;
   }
@@ -59,7 +59,7 @@ class ThrowingProcessor implements ContextProcessor {
   readonly name = 'Throwing';
   readonly id = 'Throwing';
   readonly options = {};
-  async process(): Promise<any> {
+  async process(): Promise<ReadonlyArray<import('../ir/types.js').ConcreteNode>> {
     throw new Error('Processor failed intentionally');
   }
 }
diff --git a/packages/core/src/context/sidecar/registry.test.ts b/packages/core/src/context/sidecar/registry.test.ts
index 3969ed66ca..a1d98094af 100644
--- a/packages/core/src/context/sidecar/registry.test.ts
+++ b/packages/core/src/context/sidecar/registry.test.ts
@@ -13,7 +13,7 @@ describe('SidecarRegistry', () => {
     const processorDef: ContextProcessorDef = {
       id: 'TestProcessor',
       schema: { type: 'object' },
-      create: () => ({} as any),
+      create: () => ({} as unknown as import('../pipeline.js').ContextProcessor),
     };
 
     registry.registerProcessor(processorDef);
@@ -26,7 +26,7 @@ describe('SidecarRegistry', () => {
     const workerDef: ContextWorkerDef = {
       id: 'TestWorker',
       schema: { type: 'object' },
-      create: () => ({} as any),
+      create: () => ({} as unknown as import('../pipeline.js').ContextProcessor),
     };
 
     registry.registerWorker(workerDef);
@@ -49,15 +49,15 @@ describe('SidecarRegistry', () => {
     registry.registerProcessor({
       id: 'TestProcessor',
       schema: { title: 'processorSchema' },
-      create: () => ({} as any),
+      create: () => ({} as unknown as import('../pipeline.js').ContextProcessor),
     });
     registry.registerWorker({
       id: 'TestWorker',
       schema: { title: 'workerSchema' },
-      create: () => ({} as any),
+      create: () => ({} as unknown as import('../pipeline.js').ContextProcessor),
     });
 
-    const schemas = registry.getSchemas() as any[];
+    const schemas = registry.getSchemas() as unknown as Array<Record<string, unknown>>;
     expect(schemas.length).toBe(2);
     expect(schemas.find(s => s.title === 'processorSchema')).toBeDefined();
     expect(schemas.find(s => s.title === 'workerSchema')).toBeDefined();
@@ -65,8 +65,8 @@ describe('SidecarRegistry', () => {
 
   it('should safely clear the registry', () => {
     const registry = new SidecarRegistry();
-    registry.registerProcessor({ id: 'TestProcessor', schema: {}, create: () => ({} as any) });
-    registry.registerWorker({ id: 'TestWorker', schema: {}, create: () => ({} as any) });
+    registry.registerProcessor({ id: 'TestProcessor', schema: {}, create: () => ({} as unknown as import('../pipeline.js').ContextProcessor) });
+    registry.registerWorker({ id: 'TestWorker', schema: {}, create: () => ({} as unknown as import('../pipeline.js').ContextProcessor) });
 
     registry.clear();
 
diff --git a/packages/core/src/context/testing/contextTestUtils.ts b/packages/core/src/context/testing/contextTestUtils.ts
index 6191c1d685..413b1168f8 100644
--- a/packages/core/src/context/testing/contextTestUtils.ts
+++ b/packages/core/src/context/testing/contextTestUtils.ts
@@ -29,6 +29,7 @@ import type { Content , GenerateContentResponse } from '@google/genai';
  * Used to avoid having to manually construct the deeply nested candidate/content/part structure.
  */
 export const createMockGenerateContentResponse = (text: string): GenerateContentResponse =>
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
   ({
     candidates: [{ content: { role: 'model', parts: [{ text }] }, index: 0 }],
   }) as GenerateContentResponse;
@@ -46,7 +47,7 @@ export function createDummyNode(
     id: id || randomUUID(),
     episodeId: logicalParentId,
     logicalParentId,
-    type: type as any,
+    type,
     timestamp: Date.now(),
     text: `Dummy ${type}`,
     name: type === 'SYSTEM_EVENT' ? 'dummy_event' : undefined,
@@ -94,9 +95,11 @@ export function createDummyToolNode(
 export function createMockEnvironment(
   overrides?: Partial<ContextEnvironment>,
 ): ContextEnvironment {
-  const llmClient = vi.fn().mockReturnValue({
+  const mockClient: Partial<BaseLlmClient> = {
     generateContent: vi.fn().mockResolvedValue(createMockGenerateContentResponse('Mock LLM summary response')),
-  })() as unknown as BaseLlmClient;
+  };
+  // eslint-disable-next-line @typescript-eslint/no-unsafe-type-assertion
+  const llmClient = mockClient as BaseLlmClient;
   
   const tracer = new ContextTracer({ targetDir: '/tmp', sessionId: 'mock-session' });
   const eventBus = new ContextEventBus();
@@ -114,7 +117,10 @@ export function createMockEnvironment(
     new DeterministicIdGenerator('mock-uuid-')
   );
 
-  return { ...env, ...overrides };
+  if (overrides) {
+    Object.assign(env, overrides);
+  }
+  return env;
 }
 
 /**