diff --git a/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.test.ts b/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.test.ts
index 97cf3d159a3..3e5d6769cc5 100644
--- a/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.test.ts
+++ b/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.test.ts
@@ -65,13 +65,6 @@ describe('isValidOpenRouterModelId', () => {
     };
   }
 
-  it('accepts known legacy aliases without consulting Redis', async () => {
-    const { isValidOpenRouterModelId, redisGet } = await loadValidator();
-
-    await expect(isValidOpenRouterModelId('gpt-4o')).resolves.toBe(true);
-    expect(redisGet).not.toHaveBeenCalled();
-  });
-
   it('accepts ids present in the Redis catalog', async () => {
     const { isValidOpenRouterModelId, redisGet } = await loadValidator();
     redisGet.mockResolvedValue(JSON.stringify(['openai/gpt-4o']));
diff --git a/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.ts b/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.ts
index fcdb203388a..474f5dc5831 100644
--- a/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.ts
+++ b/apps/web/src/lib/ai-gateway/providers/gateway-models-cache.ts
@@ -114,86 +114,7 @@ export const getOpenRouterModelsFromRedis = createModelIdsFetcher(
   'OpenRouter'
 );
 
-// These are (undocumented?) aliases OpenRouter accepts and were in use around 2026-08-11
-// Preferably do not add entries here, instead have the user use the documented id from the /models catalog
-const legacyOpenRouterAliases: ReadonlySet<string> = new Set([
-  'anthropic/claude-haiku-4-5',
-  'anthropic/claude-opus-4-6',
-  'anthropic/claude-sonnet-4-5',
-  'anthropic/claude-sonnet-4-6',
-  'anthropic/claude-sonnet-5-20260630',
-  'claude-fable-5',
-  'claude-haiku-4.5',
-  'claude-haiku-4-5-20251001',
-  'claude-opus-4-8',
-  'claude-opus-5',
-  'claude-sonnet-4',
-  'claude-sonnet-4.5',
-  'claude-sonnet-5',
-  'codex-auto-review',
-  'deepseek-v4-flash',
-  'deepseek-v4-flash-0731',
-  'deepseek-v4-pro',
-  'gemini-2.5-flash',
-  'gemini-2.5-flash-lite',
-  'gemini-2.5-pro',
-  'gemini-3-pro-image',
-  'gemma-4-26b-a4b-it',
-  'gemma-4-31b-it',
-  'glm-4.7-flash',
-  'glm-5.1',
-  'glm-5.2',
-  'gpt-3.5-turbo',
-  'gpt-3.5-turbo-16k',
-  'gpt-4.1',
-  'gpt-4.1-mini',
-  'gpt-4o',
-  'gpt-4o-2024-08-06',
-  'gpt-4o-mini',
-  'gpt-4o-mini-2024-07-18',
-  'gpt-5.1',
-  'gpt-5.1-codex',
-  'gpt-5.1-codex-max',
-  'gpt-5.1-codex-mini',
-  'gpt-5.2',
-  'gpt-5.2-codex',
-  'gpt-5.2-pro',
-  'gpt-5.3-codex',
-  'gpt-5.4',
-  'gpt-5.4-mini',
-  'gpt-5.4-nano',
-  'gpt-5.4-pro',
-  'gpt-5.5',
-  'gpt-5.6-luna',
-  'gpt-5.6-luna-pro',
-  'gpt-5.6-sol',
-  'gpt-5.6-terra',
-  'gpt-5-nano',
-  'gpt-5-pro',
-  'gpt-oss-20b',
-  'gpt-oss-safeguard-20b',
-  'hy3',
-  'kimi-k2.6',
-  'kimi-k3',
-  'laguna-s-2.1',
-  'laguna-xs-2.1',
-  'mimo-v2.5',
-  'minimax-m2.5',
-  'minimax-m3',
-  'minimax/minimax-m2.5-20260211',
-  'o1-pro',
-  'o3-pro',
-  'openai/gpt-4o-mini-transcribe',
-  'openai/gpt-4o-transcribe',
-  'openai/gpt-5.3-chat',
-  'qwen3.8-max',
-  'step-3.5-flash',
-]);
-
 export async function isValidOpenRouterModelId(modelId: string): Promise<boolean> {
-  if (legacyOpenRouterAliases.has(modelId)) {
-    return true;
-  }
   const openRouterModelIds = await getOpenRouterModelsFromRedis();
   if (openRouterModelIds.size === 0) {
     warnExceptInTest(