feat: add env var support for custom endpoint default models

packages/api/src/endpoints/config/models.spec.ts

@@ -0,0 +1,70 @@
+import type { AppConfig } from '@librechat/data-schemas';
+import { EModelEndpoint } from 'librechat-data-provider';
+
+import { createLoadConfigModels } from './models';
+import type { ServerRequest } from '~/types';
+
+describe('createLoadConfigModels', () => {
+  const originalEnv = process.env;
+  const getUserKeyValues = jest.fn();
+  const fetchModels = jest.fn();
+
+  beforeEach(() => {
+    process.env = {
+      ...originalEnv,
+      MULTIPLE_MODELS: 'gpt-4o-mini, gpt-4o',
+      SINGLE_MODEL: 'gpt-4.1',
+    };
+
+    getUserKeyValues.mockReset();
+    fetchModels.mockReset().mockResolvedValue([]);
+  });
+
+  afterEach(() => {
+    process.env = originalEnv;
+  });
+
+  function buildAppConfig(includeFetch = false): AppConfig {
+    return {
+      endpoints: {
+        [EModelEndpoint.custom]: [
+          {
+            name: 'custom',
+            apiKey: 'test-api-key',
+            baseURL: 'https://example.com',
+            models: {
+              default: ['${MULTIPLE_MODELS}', { name: '${SINGLE_MODEL}' }, 'claude-3-5-sonnet'],
+              ...(includeFetch ? { fetch: true } : {}),
+            },
+          },
+        ],
+      },
+    } as AppConfig;
+  }
+
+  function buildLoader(includeFetch = false) {
+    return createLoadConfigModels({
+      getAppConfig: async () => buildAppConfig(includeFetch),
+      getUserKeyValues,
+      fetchModels,
+    });
+  }
+
+  it('expands comma-separated env vars in default model lists', async () => {
+    const loadConfigModels = buildLoader(false);
+
+    const result = await loadConfigModels({} as ServerRequest);
+
+    expect(result.custom).toEqual(['gpt-4o-mini', 'gpt-4o', 'gpt-4.1', 'claude-3-5-sonnet']);
+    expect(fetchModels).not.toHaveBeenCalled();
+  });
+
+  it('uses the same expansion when falling back after a fetch miss', async () => {
+    const loadConfigModels = buildLoader(true);
+
+    const result = await loadConfigModels({} as ServerRequest);
+
+    expect(fetchModels).toHaveBeenCalledTimes(1);
+    expect(result.custom).toEqual(['gpt-4o-mini', 'gpt-4o', 'gpt-4.1', 'claude-3-5-sonnet']);
+  });
+});

packages/api/src/endpoints/config/models.ts

@@ -3,6 +3,7 @@ import {
   ErrorTypes,
   EModelEndpoint,
   extractEnvVariable,
+  extractVariableName,
   normalizeEndpointName,
 } from 'librechat-data-provider';
 import type { TModelsConfig, TEndpoint } from 'librechat-data-provider';
@@ -21,6 +22,23 @@ interface ResolvedEndpoint {
   baseURLIsUserProvided: boolean;
 }
 
+function resolveDefaultModelNames(defaultModels: TEndpoint['models']['default']): string[] {
+  return defaultModels.flatMap((model) => {
+    const rawModelName = typeof model === 'string' ? model : model.name;
+    const envVarName = extractVariableName(rawModelName);
+    const resolvedModelName = extractEnvVariable(rawModelName);
+
+    if (envVarName && resolvedModelName.includes(',')) {
+      return resolvedModelName
+        .split(',')
+        .map((name) => name.trim())
+        .filter(Boolean);
+    }
+
+    return [resolvedModelName];
+  });
+}
+
 export interface LoadConfigModelsDeps {
   getAppConfig: (params: {
     role?: string;
@@ -196,9 +214,7 @@ export function createLoadConfigModels(deps: LoadConfigModelsDeps) {
       }
 
       if (Array.isArray(models?.default)) {
-        modelsConfig[name] = models.default.map((model) =>
-          typeof model === 'string' ? model : model.name,
-        );
+        modelsConfig[name] = resolveDefaultModelNames(models.default);
       }
     }
 
@@ -216,9 +232,7 @@ export function createLoadConfigModels(deps: LoadConfigModelsDeps) {
 
       for (const name of associatedNames) {
         const endpoint = endpointsMap[name];
-        const defaults = (endpoint.models?.default ?? []).map((m) =>
-          typeof m === 'string' ? m : m.name,
-        );
+        const defaults = resolveDefaultModelNames(endpoint.models?.default ?? []);
         modelsConfig[name] = !modelData?.length ? defaults : modelData;
       }
     }