refactor: remove session model and thinking mode management from providers and related services

server/src/modules/llm/llm.routes.ts

@@ -305,56 +305,6 @@ router.post(
   }),
 );
 
-router.patch(
-  '/providers/:provider/sessions/:sessionId/model',
-  asyncHandler(async (req: Request, res: Response) => {
-    const provider = parseProvider(req.params.provider);
-    const sessionId = readPathParam(req.params.sessionId, 'sessionId');
-    const model = typeof req.body?.model === 'string' ? req.body.model.trim() : '';
-    if (!model) {
-      throw new AppError('model is required.', {
-        code: 'MODEL_REQUIRED',
-        statusCode: 400,
-      });
-    }
-
-    await llmService.setSessionModel(provider, sessionId, model);
-    res.json(
-      createApiSuccessResponse({
-        provider,
-        sessionId,
-        model,
-      }),
-    );
-  }),
-);
-
-router.patch(
-  '/providers/:provider/sessions/:sessionId/thinking',
-  asyncHandler(async (req: Request, res: Response) => {
-    const provider = parseProvider(req.params.provider);
-    const sessionId = readPathParam(req.params.sessionId, 'sessionId');
-    const thinkingMode =
-      typeof req.body?.thinkingMode === 'string' ? req.body.thinkingMode.trim() : '';
-
-    if (!thinkingMode) {
-      throw new AppError('thinkingMode is required.', {
-        code: 'THINKING_MODE_REQUIRED',
-        statusCode: 400,
-      });
-    }
-
-    await llmService.setSessionThinkingMode(provider, sessionId, thinkingMode);
-    res.json(
-      createApiSuccessResponse({
-        provider,
-        sessionId,
-        thinkingMode,
-      }),
-    );
-  }),
-);
-
 /**
  * Uploads one or more images into `.cloudcli/assets` so providers can reuse file paths.
  */

server/src/modules/llm/providers/abstract.provider.ts

@@ -1,4 +1,3 @@
-import { AppError } from '@/shared/utils/app-error.js';
 import type {
   IProvider,
   MutableProviderSession,
@@ -11,11 +10,6 @@ import type {
 } from '@/modules/llm/providers/provider.interface.js';
 import type { LLMProvider } from '@/shared/types/app.js';
 
-type SessionPreference = {
-  model?: string;
-  thinkingMode?: string;
-};
-
 const MAX_EVENT_BUFFER_SIZE = 2_000;
 
 /**
@@ -27,7 +21,6 @@ export abstract class AbstractProvider implements IProvider {
   readonly capabilities: ProviderCapabilities;
 
   protected readonly sessions = new Map<string, MutableProviderSession>();
-  protected readonly sessionPreferences = new Map<string, SessionPreference>();
 
   protected constructor(
     id: LLMProvider,
@@ -90,98 +83,6 @@ export abstract class AbstractProvider implements IProvider {
     return stopped;
   }
 
-  /**
-   * Validates/supports model switching and updates both live and persisted state.
-   */
-  async setSessionModel(sessionId: string, model: string): Promise<void> {
-    if (!this.capabilities.supportsModelSwitching) {
-      throw new AppError(`Provider "${this.id}" does not support model switching.`, {
-        code: 'MODEL_SWITCH_NOT_SUPPORTED',
-        statusCode: 400,
-      });
-    }
-
-    const trimmedModel = model.trim();
-    if (!trimmedModel) {
-      throw new AppError('Model cannot be empty.', {
-        code: 'INVALID_MODEL',
-        statusCode: 400,
-      });
-    }
-
-    const session = this.sessions.get(sessionId);
-    if (session?.setModel) {
-      await session.setModel(trimmedModel);
-    }
-
-    const currentPreference = this.sessionPreferences.get(sessionId) ?? {};
-    this.sessionPreferences.set(sessionId, { ...currentPreference, model: trimmedModel });
-
-    if (session) {
-      session.model = trimmedModel;
-      this.appendEvent(session, {
-        timestamp: new Date().toISOString(),
-        channel: 'system',
-        message: `Model updated to "${trimmedModel}".`,
-      });
-    }
-  }
-
-  /**
-   * Validates/supports thinking mode updates and applies them to live/persisted state.
-   */
-  async setSessionThinkingMode(sessionId: string, thinkingMode: string): Promise<void> {
-    if (!this.capabilities.supportsThinkingModeControl) {
-      throw new AppError(`Provider "${this.id}" does not support thinking mode control.`, {
-        code: 'THINKING_MODE_NOT_SUPPORTED',
-        statusCode: 400,
-      });
-    }
-
-    const trimmedMode = thinkingMode.trim();
-    if (!trimmedMode) {
-      throw new AppError('Thinking mode cannot be empty.', {
-        code: 'INVALID_THINKING_MODE',
-        statusCode: 400,
-      });
-    }
-
-    const session = this.sessions.get(sessionId);
-    if (session?.setThinkingMode) {
-      await session.setThinkingMode(trimmedMode);
-    }
-
-    const currentPreference = this.sessionPreferences.get(sessionId) ?? {};
-    this.sessionPreferences.set(sessionId, { ...currentPreference, thinkingMode: trimmedMode });
-
-    if (session) {
-      session.thinkingMode = trimmedMode;
-      this.appendEvent(session, {
-        timestamp: new Date().toISOString(),
-        channel: 'system',
-        message: `Thinking mode updated to "${trimmedMode}".`,
-      });
-    }
-  }
-
-  /**
-   * Reads saved preferences for resumed sessions.
-   */
-  protected getSessionPreference(sessionId: string): SessionPreference {
-    return this.sessionPreferences.get(sessionId) ?? {};
-  }
-
-  /**
-   * Stores session preferences for subsequent resume/start operations.
-   */
-  protected rememberSessionPreference(sessionId: string, preference: SessionPreference): void {
-    const currentPreference = this.sessionPreferences.get(sessionId) ?? {};
-    this.sessionPreferences.set(sessionId, {
-      ...currentPreference,
-      ...preference,
-    });
-  }
-
   /**
    * Creates mutable internal session state and registers it in memory.
    */
@@ -206,10 +107,6 @@ export abstract class AbstractProvider implements IProvider {
     };
 
     this.sessions.set(sessionId, session);
-    this.rememberSessionPreference(sessionId, {
-      model: input.model,
-      thinkingMode: input.thinkingMode,
-    });
 
     this.appendEvent(session, {
       timestamp: session.startedAt,

server/src/modules/llm/providers/base-cli.provider.ts

@@ -133,20 +133,12 @@ export abstract class BaseCliProvider extends AbstractProvider {
    * Boots one CLI child process and wires stream handlers to the session buffer.
    */
   private async startSessionInternal(input: CreateCliInvocationInput): Promise<ProviderSessionSnapshot> {
-    const preferred = this.getSessionPreference(input.sessionId);
-    const effectiveModel = input.model ?? preferred.model;
-    const effectiveThinking = input.thinkingMode ?? preferred.thinkingMode;
-
     const session = this.createSessionRecord(input.sessionId, {
-      model: effectiveModel,
-      thinkingMode: effectiveThinking,
+      model: input.model,
+      thinkingMode: input.thinkingMode,
     });
 
-    const invocation = this.createCliInvocation({
-      ...input,
-      model: effectiveModel,
-      thinkingMode: effectiveThinking,
-    });
+    const invocation = this.createCliInvocation(input);
 
     const child = spawn(invocation.command, invocation.args, {
       cwd: invocation.cwd ?? input.workspacePath ?? process.cwd(),

server/src/modules/llm/providers/base-sdk.provider.ts

@@ -19,8 +19,6 @@ type CreateSdkExecutionInput = StartSessionInput & {
 type SdkExecution = {
   stream: AsyncIterable<unknown>;
   stop: () => Promise<boolean>;
-  setModel?: (model: string) => Promise<void>;
-  setThinkingMode?: (thinkingMode: string) => Promise<void>;
 };
 
 /**
@@ -72,21 +70,15 @@ export abstract class BaseSdkProvider extends AbstractProvider {
    * Initializes one SDK execution and wires it to the internal session record.
    */
   private async startSessionInternal(input: CreateSdkExecutionInput): Promise<ProviderSessionSnapshot> {
-    const preferred = this.getSessionPreference(input.sessionId);
-    const effectiveModel = input.model ?? preferred.model;
-    const effectiveThinking = input.thinkingMode ?? preferred.thinkingMode;
-
     const session = this.createSessionRecord(input.sessionId, {
-      model: effectiveModel,
-      thinkingMode: effectiveThinking,
+      model: input.model,
+      thinkingMode: input.thinkingMode,
     });
 
     let execution: SdkExecution;
     try {
       execution = await this.createSdkExecution({
         ...input,
-        model: effectiveModel,
-        thinkingMode: effectiveThinking,
         emitEvent: (event) => {
           this.appendEvent(session, event);
         },
@@ -103,8 +95,6 @@ export abstract class BaseSdkProvider extends AbstractProvider {
     }
 
     session.stop = execution.stop;
-    session.setModel = execution.setModel;
-    session.setThinkingMode = execution.setThinkingMode;
 
     session.completion = this.consumeStream(session, execution.stream);
     return this.toSnapshot(session);

server/src/modules/llm/providers/claude.provider.ts

@@ -104,7 +104,6 @@ export class ClaudeProvider extends BaseSdkProvider {
   protected async createSdkExecution(input: ClaudeExecutionInput): Promise<{
     stream: AsyncIterable<unknown>;
     stop: () => Promise<boolean>;
-    setModel: (model: string) => Promise<void>;
   }> {
     const options: Options = {
       cwd: input.workspacePath,
@@ -131,9 +130,6 @@ export class ClaudeProvider extends BaseSdkProvider {
         await queryInstance.interrupt();
         return true;
       },
-      setModel: async (model: string) => {
-        await queryInstance.setModel(model);
-      },
     };
   }
 

server/src/modules/llm/providers/provider.interface.ts

@@ -84,8 +84,6 @@ export interface IProvider {
   resumeSession(input: StartSessionInput & { sessionId: string }): Promise<ProviderSessionSnapshot>;
 
   stopSession(sessionId: string): Promise<boolean>;
-  setSessionModel(sessionId: string, model: string): Promise<void>;
-  setSessionThinkingMode(sessionId: string, thinkingMode: string): Promise<void>;
 
   getSession(sessionId: string): ProviderSessionSnapshot | null;
   listSessions(): ProviderSessionSnapshot[];
@@ -98,6 +96,4 @@ export type MutableProviderSession = Omit<ProviderSessionSnapshot, 'events'> & {
   events: ProviderSessionEvent[];
   completion: Promise<void>;
   stop: () => Promise<boolean>;
-  setModel?: (model: string) => Promise<void>;
-  setThinkingMode?: (thinkingMode: string) => Promise<void>;
 };

server/src/modules/llm/services/llm.service.ts

@@ -127,20 +127,6 @@ export const llmService = {
     const provider = llmProviderRegistry.resolveProvider(providerName);
     return provider.stopSession(sessionId);
   },
-
-  async setSessionModel(providerName: string, sessionId: string, model: string): Promise<void> {
-    const provider = llmProviderRegistry.resolveProvider(providerName);
-    await provider.setSessionModel(sessionId, model);
-  },
-
-  async setSessionThinkingMode(
-    providerName: string,
-    sessionId: string,
-    thinkingMode: string,
-  ): Promise<void> {
-    const provider = llmProviderRegistry.resolveProvider(providerName);
-    await provider.setSessionThinkingMode(sessionId, thinkingMode);
-  },
 };
 
 /**

server/src/modules/llm/tests/llm-unifier.providers.test.ts

@@ -220,15 +220,15 @@ test('codex provider reads models_cache.json and maps model metadata', async ()
   }
 });
 
-// This test covers persisted session-level model/thinking preferences flowing into Codex thread options.
-test('codex provider applies saved model/thinking preferences on subsequent launch', async () => {
+// This test covers explicit start/resume payload control for model/thinking without implicit persistence.
+test('codex provider does not persist model/thinking between launches', async () => {
   const provider = new CodexProvider() as any;
-  let threadOptions: Record<string, unknown> | null = null;
+  const threadOptionsHistory: Record<string, unknown>[] = [];
 
   provider.loadCodexSdkModule = async () => ({
     Codex: class {
       startThread(options?: Record<string, unknown>) {
-        threadOptions = options ?? null;
+        threadOptionsHistory.push(options ?? {});
         return {
           async runStreamed() {
             return { events: asyncEvents([]) };
@@ -246,17 +246,23 @@ test('codex provider applies saved model/thinking preferences on subsequent laun
     },
   });
 
-  await provider.setSessionModel('codex-pref-1', 'gpt-5.4');
-  await provider.setSessionThinkingMode('codex-pref-1', 'xhigh');
+  await provider.launchSession({
+    prompt: 'explicit launch options',
+    sessionId: 'codex-pref-1',
+    model: 'gpt-5.4',
+    thinkingMode: 'xhigh',
+  });
 
   await provider.launchSession({
-    prompt: 'use stored preferences',
+    prompt: 'follow-up launch without options',
     sessionId: 'codex-pref-1',
   });
 
-  assert.ok(threadOptions);
-  assert.equal((threadOptions as { model?: string }).model, 'gpt-5.4');
-  assert.equal((threadOptions as { modelReasoningEffort?: string }).modelReasoningEffort, 'xhigh');
+  assert.equal(threadOptionsHistory.length, 2);
+  assert.equal((threadOptionsHistory[0] as { model?: string }).model, 'gpt-5.4');
+  assert.equal((threadOptionsHistory[0] as { modelReasoningEffort?: string }).modelReasoningEffort, 'xhigh');
+  assert.equal((threadOptionsHistory[1] as { model?: string }).model, undefined);
+  assert.equal((threadOptionsHistory[1] as { modelReasoningEffort?: string }).modelReasoningEffort, undefined);
 });
 
 // This test covers Claude thinking-level mapping, runtime permission handlers, and model/event normalization.
@@ -318,21 +324,3 @@ test('llmService rejects unsupported runtime permission and thinking mode combin
       error.statusCode === 400,
   );
 });
-
-// This test covers model/thinking capability gates on providers before any external process/SDK usage.
-test('providers enforce capability gates for model/thinking updates', async () => {
-  const claudeProvider = new ClaudeProvider();
-  const cursorProvider = new CursorProvider();
-
-  await assert.rejects(
-    cursorProvider.setSessionThinkingMode('cursor-session', 'high'),
-    (error: unknown) =>
-      error instanceof AppError &&
-      error.code === 'THINKING_MODE_NOT_SUPPORTED' &&
-      error.statusCode === 400,
-  );
-
-  await claudeProvider.setSessionModel('claude-session', 'sonnet');
-  const preference = (claudeProvider as any).getSessionPreference('claude-session');
-  assert.equal(preference.model, 'sonnet');
-});