diff --git a/src/features/background-agent/fallback-retry-handler.test.ts b/src/features/background-agent/fallback-retry-handler.test.ts
index 689785ba2..78e632bd2 100644
--- a/src/features/background-agent/fallback-retry-handler.test.ts
+++ b/src/features/background-agent/fallback-retry-handler.test.ts
@@ -1,33 +1,52 @@
 import { afterAll, beforeEach, describe, expect, mock, test } from "bun:test"
 
-mock.module("../../shared/logger", () => ({
-  log: mock(() => {}),
-}))
-
-mock.module("../../shared/connected-providers-cache", () => ({
-  readConnectedProvidersCache: mock(() => null),
-  readProviderModelsCache: mock(() => null),
-}))
-
-mock.module("../../shared/model-error-classifier", () => ({
-  shouldRetryError: mock(() => true),
-  getNextFallback: mock((chain: Array<{ model: string }>, attempt: number) => chain[attempt]),
-  hasMoreFallbacks: mock((chain: Array<{ model: string }>, attempt: number) => attempt < chain.length),
-  selectFallbackProvider: mock((providers: string[]) => providers[0]),
-}))
-
-mock.module("../../shared/provider-model-id-transform", () => ({
-  transformModelForProvider: mock((_provider: string, model: string) => model),
-}))
+const sharedLogMock = mock(() => {})
+const readConnectedProvidersCacheMock = mock(() => null)
+const readProviderModelsCacheMock = mock(() => null)
+const shouldRetryErrorMock = mock(() => true)
+const getNextFallbackMock = mock((chain: Array<{ model: string }>, attempt: number) => chain[attempt])
+const hasMoreFallbacksMock = mock((chain: Array<{ model: string }>, attempt: number) => attempt < chain.length)
+const selectFallbackProviderMock = mock((providers: string[]) => providers[0])
+const transformModelForProviderMock = mock((_provider: string, model: string) => model)
 
 import type { BackgroundTask } from "./types"
 import type { ConcurrencyManager } from "./concurrency"
 import type { OpencodeClient, QueueItem } from "./constants"
 
-const { tryFallbackRetry } = await import("./fallback-retry-handler")
-const { shouldRetryError, selectFallbackProvider } = await import("../../shared/model-error-classifier")
-const { readProviderModelsCache } = await import("../../shared")
-mock.restore()
+async function importFreshFallbackRetryHandlerModule() {
+  mock.module("../../shared/logger", () => ({
+    log: sharedLogMock,
+  }))
+
+  mock.module("../../shared/connected-providers-cache", () => ({
+    readConnectedProvidersCache: readConnectedProvidersCacheMock,
+    readProviderModelsCache: readProviderModelsCacheMock,
+  }))
+
+  mock.module("../../shared/model-error-classifier", () => ({
+    shouldRetryError: shouldRetryErrorMock,
+    getNextFallback: getNextFallbackMock,
+    hasMoreFallbacks: hasMoreFallbacksMock,
+    selectFallbackProvider: selectFallbackProviderMock,
+  }))
+
+  mock.module("../../shared/provider-model-id-transform", () => ({
+    transformModelForProvider: transformModelForProviderMock,
+  }))
+
+  const retryHandlerModule = await import(`./fallback-retry-handler?test=${Date.now()}-${Math.random()}`)
+  mock.restore()
+
+  return {
+    tryFallbackRetry: retryHandlerModule.tryFallbackRetry,
+    shouldRetryError: shouldRetryErrorMock,
+    selectFallbackProvider: selectFallbackProviderMock,
+    readProviderModelsCache: readProviderModelsCacheMock,
+  }
+}
+
+const { tryFallbackRetry, shouldRetryError, selectFallbackProvider, readProviderModelsCache } =
+  await importFreshFallbackRetryHandlerModule()
 
 function createDeferredPromise(): {
   promise: Promise<void>
diff --git a/src/features/skill-mcp-manager/manager.test.ts b/src/features/skill-mcp-manager/manager.test.ts
index 5a3525a0b..541ab18f8 100644
--- a/src/features/skill-mcp-manager/manager.test.ts
+++ b/src/features/skill-mcp-manager/manager.test.ts
@@ -1,5 +1,4 @@
 import { describe, it, expect, beforeEach, afterEach, afterAll, mock, spyOn } from "bun:test"
-import { SkillMcpManager } from "./manager"
 import type { SkillMcpClientInfo, SkillMcpServerContext } from "./types"
 import type { ClaudeCodeMcpServer } from "../claude-code-mcp-loader/types"
 
@@ -8,41 +7,50 @@ const mockHttpConnect = mock(() => Promise.reject(new Error("Mocked HTTP connect
 const mockHttpClose = mock(() => Promise.resolve())
 let lastTransportInstance: { url?: URL; options?: { requestInit?: RequestInit } } = {}
 
-mock.module("@modelcontextprotocol/sdk/client/streamableHttp.js", () => ({
-  StreamableHTTPClientTransport: class MockStreamableHTTPClientTransport {
-    constructor(public url: URL, public options?: { requestInit?: RequestInit }) {
-      lastTransportInstance = { url, options }
-    }
-    async start() {
-      await mockHttpConnect()
-    }
-    async close() {
-      await mockHttpClose()
-    }
-  },
-}))
-
 // Mock OAuth provider for OAuth integration tests
 const mockTokens = mock(() => null as { accessToken: string } | null)
 const mockLogin = mock(() => Promise.resolve({ accessToken: "test-token" }) as Promise<{ accessToken: string } | null>)
 
-mock.module("../mcp-oauth/provider", () => ({
-  McpOAuthProvider: class MockMcpOAuthProvider {
-    tokens = mockTokens
-    login = mockLogin
-    constructor(_opts: unknown) {}
-  },
-}))
+async function importFreshManagerModule(): Promise<typeof import("./manager")> {
+  mock.module("@modelcontextprotocol/sdk/client/streamableHttp.js", () => ({
+    StreamableHTTPClientTransport: class MockStreamableHTTPClientTransport {
+      constructor(public url: URL, public options?: { requestInit?: RequestInit }) {
+        lastTransportInstance = { url, options }
+      }
+      async start() {
+        await mockHttpConnect()
+      }
+      async close() {
+        await mockHttpClose()
+      }
+    },
+  }))
+
+  mock.module("../mcp-oauth/provider", () => ({
+    McpOAuthProvider: class MockMcpOAuthProvider {
+      tokens = mockTokens
+      login = mockLogin
+      constructor(_opts: unknown) {}
+    },
+  }))
+
+  const module = await import(`./manager?test=${Date.now()}-${Math.random()}`)
+  mock.restore()
+  return module
+}
 
 afterAll(() => { mock.restore() })
 
 describe("SkillMcpManager", () => {
-  let manager: SkillMcpManager
+  let manager: any
 
-  beforeEach(() => {
+  beforeEach(async () => {
+    const { SkillMcpManager } = await importFreshManagerModule()
     manager = new SkillMcpManager()
     mockHttpConnect.mockClear()
     mockHttpClose.mockClear()
+    mockTokens.mockClear()
+    mockLogin.mockClear()
   })
 
   afterEach(async () => {
diff --git a/src/hooks/legacy-plugin-toast/hook.test.ts b/src/hooks/legacy-plugin-toast/hook.test.ts
index e44811be5..4f889aefa 100644
--- a/src/hooks/legacy-plugin-toast/hook.test.ts
+++ b/src/hooks/legacy-plugin-toast/hook.test.ts
@@ -18,18 +18,6 @@ const mockAutoMigrate = mock((): MigrationResult => ({
 const mockShowToast = mock((_arg: any) => Promise.resolve())
 const mockLog = mock(() => {})
 
-mock.module("../../shared/legacy-plugin-warning", () => ({
-  checkForLegacyPluginEntry: mockCheckForLegacyPluginEntry,
-}))
-
-mock.module("../../shared/logger", () => ({
-  log: mockLog,
-}))
-
-mock.module("./auto-migrate-runner", () => ({
-  autoMigrateLegacyPluginEntry: mockAutoMigrate,
-}))
-
 afterAll(() => {
   mock.restore()
 })
@@ -53,6 +41,18 @@ function createEvent(type: string, parentID?: string) {
 }
 
 async function importFreshModule() {
+  mock.module("../../shared/legacy-plugin-warning", () => ({
+    checkForLegacyPluginEntry: mockCheckForLegacyPluginEntry,
+  }))
+
+  mock.module("../../shared/logger", () => ({
+    log: mockLog,
+  }))
+
+  mock.module("./auto-migrate-runner", () => ({
+    autoMigrateLegacyPluginEntry: mockAutoMigrate,
+  }))
+
   const module = await import(`./hook?t=${Date.now()}-${Math.random()}`)
   mock.restore()
   return module
diff --git a/src/hooks/model-fallback/hook.test.ts b/src/hooks/model-fallback/hook.test.ts
index a401314ab..8c59db5f5 100644
--- a/src/hooks/model-fallback/hook.test.ts
+++ b/src/hooks/model-fallback/hook.test.ts
@@ -40,30 +40,35 @@ const transformModelForProviderMock = mock((provider: string, model: string) =>
   return model
 })
 
-mock.module("../../shared/connected-providers-cache", () => ({
-  readConnectedProvidersCache: readConnectedProvidersCacheMock,
-  readProviderModelsCache: readProviderModelsCacheMock,
-}))
-
-mock.module("../../shared/provider-model-id-transform", () => ({
-  transformModelForProvider: transformModelForProviderMock,
-}))
-
-mock.module("../../shared/model-error-classifier", () => ({
-  selectFallbackProvider: selectFallbackProviderMock,
-}))
-
 afterAll(() => {
   mock.restore()
 })
 
+async function importFreshModelFallbackHookModule() {
+  mock.module("../../shared/connected-providers-cache", () => ({
+    readConnectedProvidersCache: readConnectedProvidersCacheMock,
+    readProviderModelsCache: readProviderModelsCacheMock,
+  }))
+
+  mock.module("../../shared/provider-model-id-transform", () => ({
+    transformModelForProvider: transformModelForProviderMock,
+  }))
+
+  mock.module("../../shared/model-error-classifier", () => ({
+    selectFallbackProvider: selectFallbackProviderMock,
+  }))
+
+  const module = await import(`./hook?test=${Date.now()}-${Math.random()}`)
+  mock.restore()
+  return module
+}
+
 const {
   clearPendingModelFallback,
   createModelFallbackHook,
   setSessionFallbackChain,
   setPendingModelFallback,
-} = await import("./hook")
-mock.restore()
+} = await importFreshModelFallbackHookModule()
 
 describe("model fallback hook", () => {
   beforeEach(() => {
diff --git a/src/hooks/rules-injector/injector.test.ts b/src/hooks/rules-injector/injector.test.ts
index 6df726e7c..129d6364b 100644
--- a/src/hooks/rules-injector/injector.test.ts
+++ b/src/hooks/rules-injector/injector.test.ts
@@ -1,4 +1,4 @@
-import { afterAll, afterEach, beforeEach, describe, expect, it, mock } from "bun:test";
+import { afterEach, beforeEach, describe, expect, it, mock } from "bun:test";
 import * as fs from "node:fs";
 import { mkdirSync, rmSync, writeFileSync } from "node:fs";
 import * as os from "node:os";
@@ -17,45 +17,6 @@ const originalReadFileSync = fs.readFileSync.bind(fs);
 const originalStatSync = fs.statSync.bind(fs);
 const originalHomedir = os.homedir.bind(os);
 
-mock.module("node:fs", () => ({
-  ...fs,
-  readFileSync: (filePath: string, encoding?: string) => {
-    if (filePath === trackedRulePath) {
-      trackedReadFileCount += 1;
-    }
-    return originalReadFileSync(filePath, encoding as never);
-  },
-  statSync: (filePath: string) => {
-    if (filePath === trackedRulePath) {
-      const next = statSnapshots.shift();
-      if (next instanceof Error) {
-        throw next;
-      }
-      if (next) {
-        return {
-          mtimeMs: next.mtimeMs,
-          size: next.size,
-          isFile: () => true,
-        } as ReturnType<typeof originalStatSync>;
-      }
-    }
-    return originalStatSync(filePath);
-  },
-}));
-
-mock.module("node:os", () => ({
-  ...os,
-  homedir: () => mockedHomeDir || originalHomedir(),
-}));
-
-mock.module("./matcher", () => ({
-  shouldApplyRule: () => ({ applies: true, reason: "matched" }),
-  isDuplicateByRealPath: (realPath: string, cache: Set<string>) =>
-    cache.has(realPath),
-  createContentHash: (content: string) => `hash:${content}`,
-  isDuplicateByContentHash: (hash: string, cache: Set<string>) => cache.has(hash),
-}));
-
 function createOutput(): { title: string; output: string; metadata: unknown } {
   return { title: "tool", output: "", metadata: {} };
 }
@@ -67,7 +28,47 @@ async function createProcessor(projectRoot: string): Promise<{
     output: { title: string; output: string; metadata: unknown }
   ) => Promise<void>;
 }> {
-  const { createRuleInjectionProcessor } = await import("./injector");
+  mock.module("node:fs", () => ({
+    ...fs,
+    readFileSync: (filePath: string, encoding?: string) => {
+      if (filePath === trackedRulePath) {
+        trackedReadFileCount += 1;
+      }
+      return originalReadFileSync(filePath, encoding as never);
+    },
+    statSync: (filePath: string) => {
+      if (filePath === trackedRulePath) {
+        const next = statSnapshots.shift();
+        if (next instanceof Error) {
+          throw next;
+        }
+        if (next) {
+          return {
+            mtimeMs: next.mtimeMs,
+            size: next.size,
+            isFile: () => true,
+          } as ReturnType<typeof originalStatSync>;
+        }
+      }
+      return originalStatSync(filePath);
+    },
+  }));
+
+  mock.module("node:os", () => ({
+    ...os,
+    homedir: () => mockedHomeDir || originalHomedir(),
+  }));
+
+  mock.module("./matcher", () => ({
+    shouldApplyRule: () => ({ applies: true, reason: "matched" }),
+    isDuplicateByRealPath: (realPath: string, cache: Set<string>) =>
+      cache.has(realPath),
+    createContentHash: (content: string) => `hash:${content}`,
+    isDuplicateByContentHash: (hash: string, cache: Set<string>) => cache.has(hash),
+  }));
+
+  const { createRuleInjectionProcessor } = await import(`./injector?test=${Date.now()}-${Math.random()}`);
+  mock.restore();
   const sessionCaches = new Map<
     string,
     { contentHashes: Set<string>; realPaths: Set<string> }
@@ -102,10 +103,6 @@ function getInjectedRulesPath(sessionID: string): string {
 }
 
 describe("createRuleInjectionProcessor", () => {
-  afterAll(() => {
-    mock.restore();
-  });
-
   let testRoot: string;
   let projectRoot: string;
   let homeRoot: string;
diff --git a/src/shared/log-legacy-plugin-startup-warning.test.ts b/src/shared/log-legacy-plugin-startup-warning.test.ts
index 41a034975..421d2a7f3 100644
--- a/src/shared/log-legacy-plugin-startup-warning.test.ts
+++ b/src/shared/log-legacy-plugin-startup-warning.test.ts
@@ -20,23 +20,23 @@ const mockLog = mock(() => {})
 const mockMigrateLegacyPluginEntry = mock(() => false)
 let consoleWarnSpy: ReturnType<typeof spyOn>
 
-mock.module("./legacy-plugin-warning", () => ({
-  checkForLegacyPluginEntry: mockCheckForLegacyPluginEntry,
-}))
-
-mock.module("./logger", () => ({
-  log: mockLog,
-}))
-
-mock.module("./migrate-legacy-plugin-entry", () => ({
-  migrateLegacyPluginEntry: mockMigrateLegacyPluginEntry,
-}))
-
 afterAll(() => {
   mock.restore()
 })
 
 async function importFreshStartupWarningModule(): Promise<typeof import("./log-legacy-plugin-startup-warning")> {
+  mock.module("./legacy-plugin-warning", () => ({
+    checkForLegacyPluginEntry: mockCheckForLegacyPluginEntry,
+  }))
+
+  mock.module("./logger", () => ({
+    log: mockLog,
+  }))
+
+  mock.module("./migrate-legacy-plugin-entry", () => ({
+    migrateLegacyPluginEntry: mockMigrateLegacyPluginEntry,
+  }))
+
   const module = await import(`./log-legacy-plugin-startup-warning?test=${Date.now()}-${Math.random()}`)
   mock.restore()
   consoleWarnSpy = spyOn(console, "warn").mockImplementation(() => {})
diff --git a/src/shared/model-capabilities.test.ts b/src/shared/model-capabilities.test.ts
index 917b4518a..711ee7906 100644
--- a/src/shared/model-capabilities.test.ts
+++ b/src/shared/model-capabilities.test.ts
@@ -1,22 +1,27 @@
 import type { ModelCapabilitiesSnapshot } from "./model-capabilities"
 import { afterAll, describe, expect, test, mock } from "bun:test"
 
-// Mock connected-providers-cache to prevent local disk cache from polluting test results.
-// Without this, findProviderModelMetadata reads real cached model metadata (e.g., from opencode serve)
-// which causes the "prefers runtime models.dev cache" test to get different values than expected.
-mock.module("./connected-providers-cache", () => ({
-  findProviderModelMetadata: () => undefined,
-  readConnectedProvidersCache: () => null,
-  hasConnectedProvidersCache: () => false,
-  hasProviderModelsCache: () => false,
-}))
-
 afterAll(() => {
   mock.restore()
 })
 
-const { getModelCapabilities, getBundledModelCapabilitiesSnapshot } = await import("./model-capabilities")
-mock.restore()
+async function importFreshModelCapabilitiesModule() {
+  // Mock connected-providers-cache to prevent local disk cache from polluting test results.
+  // Without this, findProviderModelMetadata reads real cached model metadata (e.g., from opencode serve)
+  // which causes the "prefers runtime models.dev cache" test to get different values than expected.
+  mock.module("./connected-providers-cache", () => ({
+    findProviderModelMetadata: () => undefined,
+    readConnectedProvidersCache: () => null,
+    hasConnectedProvidersCache: () => false,
+    hasProviderModelsCache: () => false,
+  }))
+
+  const module = await import(`./model-capabilities?test=${Date.now()}-${Math.random()}`)
+  mock.restore()
+  return module
+}
+
+const { getModelCapabilities, getBundledModelCapabilitiesSnapshot } = await importFreshModelCapabilitiesModule()
 import { AGENT_MODEL_REQUIREMENTS, CATEGORY_MODEL_REQUIREMENTS } from "./model-requirements"
 
 describe("getModelCapabilities", () => {
diff --git a/src/shared/model-error-classifier.test.ts b/src/shared/model-error-classifier.test.ts
index 4cb870803..60c2572a9 100644
--- a/src/shared/model-error-classifier.test.ts
+++ b/src/shared/model-error-classifier.test.ts
@@ -3,14 +3,19 @@ const { describe, expect, test, beforeEach, mock, afterAll } = require("bun:test
 
 const readConnectedProvidersCacheMock = mock(() => null)
 
-mock.module("./connected-providers-cache", () => ({
-  readConnectedProvidersCache: readConnectedProvidersCacheMock,
-}))
+async function importFreshModelErrorClassifierModule() {
+  mock.module("./connected-providers-cache", () => ({
+    readConnectedProvidersCache: readConnectedProvidersCacheMock,
+  }))
+
+  const module = await import(`./model-error-classifier?test=${Date.now()}-${Math.random()}`)
+  mock.restore()
+  return module
+}
 
 afterAll(() => { mock.restore() })
 
-const { shouldRetryError, selectFallbackProvider } = await import("./model-error-classifier")
-mock.restore()
+const { shouldRetryError, selectFallbackProvider } = await importFreshModelErrorClassifierModule()
 
 describe("model-error-classifier", () => {
   beforeEach(() => {
diff --git a/src/tools/skill/tools.test.ts b/src/tools/skill/tools.test.ts
index bf7ebf451..5a51bec7a 100644
--- a/src/tools/skill/tools.test.ts
+++ b/src/tools/skill/tools.test.ts
@@ -1,7 +1,6 @@
 import { afterAll, beforeEach, describe, expect, it, mock, spyOn } from "bun:test"
 import type { ToolContext } from "@opencode-ai/plugin/tool"
 import * as fs from "node:fs"
-import { createSkillTool } from "./tools"
 import { SkillMcpManager } from "../../features/skill-mcp-manager"
 import type { LoadedSkill } from "../../features/opencode-skill-loader/types"
 import type { CommandInfo } from "../slashcommand/types"
@@ -9,18 +8,26 @@ import type { Tool as McpTool } from "@modelcontextprotocol/sdk/types.js"
 
 const originalReadFileSync = fs.readFileSync.bind(fs)
 
-mock.module("node:fs", () => ({
-  ...fs,
-  readFileSync: (path: string, encoding?: string) => {
-    if (typeof path === "string" && path.includes("/skills/")) {
-      return `---
+async function importFreshSkillToolModule(): Promise<typeof import("./tools")> {
+  mock.module("node:fs", () => ({
+    ...fs,
+    readFileSync: (path: string, encoding?: string) => {
+      if (typeof path === "string" && path.includes("/skills/")) {
+        return `---
 description: Test skill description
 ---
 Test skill body content`
-    }
-    return originalReadFileSync(path, encoding as BufferEncoding)
-  },
-}))
+      }
+      return originalReadFileSync(path, encoding as BufferEncoding)
+    },
+  }))
+
+  const module = await import(`./tools?test=${Date.now()}-${Math.random()}`)
+  mock.restore()
+  return module
+}
+
+const { createSkillTool } = await importFreshSkillToolModule()
 
 afterAll(() => {
   mock.restore()