DeepSeek | Preserve configured model prefix

lib/llm/model-ref.js

@@ -26,6 +26,7 @@ const PROVIDERS = {
  * @property {string} provider
  * @property {string} modelId
  * @property {string} prefix
+ * @property {string} modelPrefix
  * @property {string} raw
  * @property {string} apiKeyName
  */
@@ -56,7 +57,8 @@ export function parseModelRef(modelRef) {
     throw modelRefError(raw);
   }
 
-  const prefix = raw.slice(0, slash).trim().toLowerCase().replace(/^~/, '');
+  const modelPrefix = raw.slice(0, slash).trim();
+  const prefix = modelPrefix.toLowerCase().replace(/^~/, '');
   const modelId = raw.slice(slash + 1).trim();
   if (!prefix || !modelId) {
     throw modelRefError(raw);
@@ -71,6 +73,7 @@ export function parseModelRef(modelRef) {
     provider: provider.name,
     modelId,
     prefix,
+    modelPrefix,
     raw,
     apiKeyName: provider.apiKeyName,
   };

lib/llm/openai.js

@@ -6,8 +6,8 @@
  * OpenAI-compatible host. When both DeepSeek vars are unset, DeepSeek
  * traffic reuses the OpenAI key/URL (production proxy hack in
  * lib/llm/provider.js). OpenAI model ids may still use an `openai/`
- * prefix; it is stripped before the API call. DeepSeek needs the full
- * `~deepseek/…` model name on the wire.
+ * prefix; it is stripped before the API call. DeepSeek preserves the
+ * `deepseek/` or `~deepseek/` prefix supplied by the caller.
  */
 
 import OpenAI from 'openai';
@@ -26,14 +26,16 @@ export function normalizeOpenAiModelId(modelId = '') {
 }
 
 /**
- * DeepSeek hosts expect the full `~deepseek/…` model name, not a bare id.
- * `deepseek/…` is accepted as an alias and rewritten to `~deepseek/…`.
+ * DeepSeek hosts expect the full prefixed model name, not a bare id.
+ * Preserve whether the caller supplied `deepseek/` or `~deepseek/`.
  * @param {string} [modelId]
  * @returns {string}
  */
 export function normalizeDeepSeekModelId(modelId = '') {
-  const rest = String(modelId).trim().replace(/^(~deepseek|deepseek)\//i, '');
-  return rest ? `~deepseek/${rest}` : '';
+  const value = String(modelId).trim();
+  const match = value.match(/^(~deepseek|deepseek)\//i);
+  if (match) return `${match[1]}/${value.slice(match[0].length)}`;
+  return value ? `~deepseek/${value}` : '';
 }
 
 /**

lib/llm/provider.js

@@ -1,8 +1,7 @@
 /**
  * Resolve an LLM provider from a session model ref (`provider/model-id`).
  *
- * The prefix selects the adapter; the remainder is the API model id
- * (DeepSeek keeps a `~deepseek/` prefix on the wire).
+ * The prefix selects the adapter; the remainder is the API model id.
  * API keys and base URLs still come from the environment.
  */
 
@@ -27,7 +26,7 @@ function envVarIsSet(value) {
  *
  * In production, DEEPSEEK_API_KEY and DEEPSEEK_BASE_URL are left empty on
  * purpose. The OpenAI base URL is not api.openai.com; it is an internal
- * proxy that routes by model name, including `~deepseek/…`.
+ * proxy that routes by model name, including `deepseek/…` and `~deepseek/…`.
  *
  * This fallback is safe ONLY when both DeepSeek vars are unset/blank. If
  * either is set, the operator meant a dedicated DeepSeek (or OpenRouter)
@@ -58,16 +57,16 @@ export function requiredApiKeyName(modelRef, env = process.env) {
 
 /**
  * @param {NodeJS.ProcessEnv} env
- * @param {string} modelId
+ * @param {{ modelId: string, modelPrefix: string }} parsed
  * @returns {import('./types.js').LlmProvider}
  */
-function createDeepSeekProvider(env, modelId) {
+function createDeepSeekProvider(env, parsed) {
   // PRODUCTION HACK: see shouldFallbackDeepSeekToOpenAi(). Dedicated DeepSeek
   // credentials win; otherwise reuse the OpenAI proxy key/URL.
   // Dedicated DeepSeek must set DEEPSEEK_BASE_URL. Without it the OpenAI SDK
-  // would send ~deepseek/… to api.openai.com.
+  // would send a DeepSeek model to api.openai.com.
   const fallback = shouldFallbackDeepSeekToOpenAi(env);
-  return createOpenAiProvider(env, modelId, {
+  return createOpenAiProvider(env, `${parsed.modelPrefix}/${parsed.modelId}`, {
     name: 'deepseek',
     apiKeyEnv: fallback ? 'OPENAI_API_KEY' : 'DEEPSEEK_API_KEY',
     baseUrlEnv: fallback ? 'OPENAI_BASE_URL' : 'DEEPSEEK_BASE_URL',
@@ -89,7 +88,7 @@ export function createLlmProvider(env = process.env, modelRef) {
     case 'openai':
       return createOpenAiProvider(env, parsed.modelId);
     case 'deepseek':
-      return createDeepSeekProvider(env, parsed.modelId);
+      return createDeepSeekProvider(env, parsed);
     case 'gemini':
       return createGeminiProvider(env, parsed.modelId);
     default: {

tests/llm-openai.test.js

@@ -34,11 +34,11 @@ describe('normalizeOpenAiModelId', () => {
 });
 
 describe('normalizeDeepSeekModelId', () => {
-  it('rewrites deepseek aliases to ~deepseek/…', () => {
+  it('preserves the supplied DeepSeek prefix', () => {
     expect(normalizeDeepSeekModelId('deepseek-v4-flash-latest'))
       .toBe('~deepseek/deepseek-v4-flash-latest');
     expect(normalizeDeepSeekModelId('deepseek/deepseek-v4-flash-latest'))
-      .toBe('~deepseek/deepseek-v4-flash-latest');
+      .toBe('deepseek/deepseek-v4-flash-latest');
     expect(normalizeDeepSeekModelId('~deepseek/deepseek-v4-flash-latest'))
       .toBe('~deepseek/deepseek-v4-flash-latest');
   });
@@ -180,10 +180,10 @@ describe('createLlmProvider deepseek', () => {
 
     expect(result).toEqual({ text: 'Paris', requestId: 'chatcmpl-ds' });
     expect(logSpy).toHaveBeenCalledWith(
-      '[llm] request {"provider":"deepseek","model":"~deepseek/deepseek-v4-flash-latest","baseURL":"https://api.deepseek.test/v1","messageCount":1}',
+      '[llm] request {"provider":"deepseek","model":"deepseek/deepseek-v4-flash-latest","baseURL":"https://api.deepseek.test/v1","messageCount":1}',
     );
     expect(createMock).toHaveBeenCalledWith({
-      model: '~deepseek/deepseek-v4-flash-latest',
+      model: 'deepseek/deepseek-v4-flash-latest',
       messages: [{ role: 'user', content: 'Capital of France?' }],
     });
     logSpy.mockRestore();
@@ -200,6 +200,25 @@ describe('createLlmProvider deepseek', () => {
     });
   });
 
+  it('sends a deepseek/ model ref with its original prefix', async () => {
+    createMock.mockResolvedValue({
+      id: 'chatcmpl-ds-alias',
+      choices: [{ message: { content: 'Paris' } }],
+    });
+    const llm = createLlmProvider({
+      DEEPSEEK_API_KEY: 'sk-deepseek',
+      DEEPSEEK_BASE_URL: 'https://api.deepseek.test/v1',
+    }, 'deepseek/deepseek-v4-flash-latest');
+
+    await llm.complete({ model: llm.model, messages: [{ role: 'user', content: 'Hi' }] });
+
+    expect(llm.model).toBe('deepseek/deepseek-v4-flash-latest');
+    expect(createMock).toHaveBeenCalledWith({
+      model: 'deepseek/deepseek-v4-flash-latest',
+      messages: [{ role: 'user', content: 'Hi' }],
+    });
+  });
+
   it('falls back to OPENAI_* when both DeepSeek env vars are unset (prod proxy hack)', () => {
     createLlmProvider({
       OPENAI_API_KEY: 'sk-openai',