diff --git a/src/modules/llms/server/anthropic/anthropic.router.ts b/src/modules/llms/server/anthropic/anthropic.router.ts
index 5f3b9fabc..72597d5b1 100644
--- a/src/modules/llms/server/anthropic/anthropic.router.ts
+++ b/src/modules/llms/server/anthropic/anthropic.router.ts
@@ -1,4 +1,5 @@
 import * as z from 'zod/v4';
+import { TRPCError } from '@trpc/server';
 
 import { createTRPCRouter, publicProcedure } from '~/server/trpc/trpc.server';
 import { env } from '~/server/env';
@@ -131,7 +132,7 @@ export function anthropicAccess(access: AnthropicAccessSchema, apiPath: string,
 
   // break for the missing key only on the default host
   if (!anthropicKey && !(access.anthropicHost || env.ANTHROPIC_API_HOST))
-    throw new Error('Missing Anthropic API Key. Add it on the UI (Models Setup) or server side (your deployment).');
+    throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing Anthropic API Key. Add it on the UI (Models Setup) or server side (your deployment).' });
 
   // API host
   let anthropicHost = fixupHost(access.anthropicHost || env.ANTHROPIC_API_HOST || DEFAULT_ANTHROPIC_HOST, apiPath);
@@ -141,7 +142,7 @@ export function anthropicAccess(access: AnthropicAccessSchema, apiPath: string,
   const heliKey = access.heliconeKey || env.HELICONE_API_KEY || false;
   if (heliKey) {
     if (!anthropicHost.includes(DEFAULT_ANTHROPIC_HOST) && !anthropicHost.includes(DEFAULT_HELICONE_ANTHROPIC_HOST))
-      throw new Error(`The Helicone Anthropic Key has been provided, but the host is set to custom. Please fix it in the Models Setup page.`);
+      throw new TRPCError({ code: 'BAD_REQUEST', message: 'The Helicone Anthropic Key has been provided, but the host is set to custom. Please fix it in the Models Setup page.' });
     anthropicHost = `https://${DEFAULT_HELICONE_ANTHROPIC_HOST}`;
   }
 
diff --git a/src/modules/llms/server/gemini/gemini.router.ts b/src/modules/llms/server/gemini/gemini.router.ts
index 69f33de1c..93bb93473 100644
--- a/src/modules/llms/server/gemini/gemini.router.ts
+++ b/src/modules/llms/server/gemini/gemini.router.ts
@@ -1,4 +1,5 @@
 import * as z from 'zod/v4';
+import { TRPCError } from '@trpc/server';
 import { env } from '~/server/env';
 
 import packageJson from '../../../../../package.json';
@@ -36,7 +37,7 @@ export function geminiAccess(access: GeminiAccessSchema, modelRefId: string | nu
   // update model-dependent paths
   if (apiPath.includes('{model=models/*}')) {
     if (!modelRefId)
-      throw new Error(`geminiAccess: modelRefId is required for ${apiPath}`);
+      throw new TRPCError({ code: 'BAD_REQUEST', message: `geminiAccess: modelRefId is required for ${apiPath}` });
     apiPath = apiPath.replace('{model=models/*}', modelRefId);
   }
 
diff --git a/src/modules/llms/server/openai/openai.router.ts b/src/modules/llms/server/openai/openai.router.ts
index 9236454e1..9ff4609da 100644
--- a/src/modules/llms/server/openai/openai.router.ts
+++ b/src/modules/llms/server/openai/openai.router.ts
@@ -542,7 +542,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       alibabaOaiKey = getRandomKeyFromMultiKey(alibabaOaiKey);
 
       if (!alibabaOaiKey || !alibabaOaiHost)
-        throw new Error('Missing Alibaba API Key. Add it on the UI or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing Alibaba API Key. Add it on the UI or server side (your deployment).' });
 
       return {
         headers: {
@@ -567,7 +567,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       deepseekKey = getRandomKeyFromMultiKey(deepseekKey);
 
       if (!deepseekKey || !deepseekHost)
-        throw new Error('Missing Deepseek API Key or Host. Add it on the UI (Models Setup) or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing Deepseek API Key or Host. Add it on the UI (Models Setup) or server side (your deployment).' });
 
       return {
         headers: {
@@ -585,7 +585,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       let oaiHost = fixupHost(access.oaiHost || env.OPENAI_API_HOST || DEFAULT_OPENAI_HOST, apiPath);
       // warn if no key - only for default (non-overridden) hosts
       if (!oaiKey && oaiHost.indexOf(DEFAULT_OPENAI_HOST) !== -1)
-        throw new Error('Missing OpenAI API Key. Add it on the UI or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing OpenAI API Key. Add it on the UI or server side (your deployment).' });
 
       // [Helicone]
       // We don't change the host (as we do on Anthropic's), as we expect the user to have a custom host.
@@ -607,11 +607,11 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
 
         // The expected path should be: /v1/<ACCOUNT_TAG>/<GATEWAY_URL_SLUG>/<PROVIDER_ENDPOINT>
         if (pathSegments.length < 3 || pathSegments.length > 4 || pathSegments[0] !== 'v1')
-          throw new Error('Cloudflare AI Gateway API Host is not valid. Please check the API Host field in the Models Setup page.');
+          throw new TRPCError({ code: 'BAD_REQUEST', message: 'Cloudflare AI Gateway API Host is not valid. Please check the API Host field in the Models Setup page.' });
 
         const [_v1, accountTag, gatewayName, provider] = pathSegments;
         if (provider && provider !== 'openai')
-          throw new Error('Cloudflare AI Gateway only supports OpenAI as a provider.');
+          throw new TRPCError({ code: 'BAD_REQUEST', message: 'Cloudflare AI Gateway only supports OpenAI as a provider.' });
 
         if (apiPath.startsWith('/v1'))
           apiPath = apiPath.replace('/v1', '');
@@ -638,7 +638,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       groqKey = getRandomKeyFromMultiKey(groqKey);
 
       if (!groqKey)
-        throw new Error('Missing Groq API Key. Add it on the UI (Models Setup) or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing Groq API Key. Add it on the UI (Models Setup) or server side (your deployment).' });
 
       return {
         headers: {
@@ -683,7 +683,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
     case 'openpipe':
       const openPipeKey = access.oaiKey || env.OPENPIPE_API_KEY || '';
       if (!openPipeKey)
-        throw new Error('Missing OpenPipe API Key or Host. Add it on the UI or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing OpenPipe API Key or Host. Add it on the UI or server side (your deployment).' });
 
       return {
         headers: {
@@ -703,7 +703,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       orKey = getRandomKeyFromMultiKey(orKey);
 
       if (!orKey || !orHost)
-        throw new Error('Missing OpenRouter API Key or Host. Add it on the UI or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing OpenRouter API Key or Host. Add it on the UI or server side (your deployment).' });
 
       return {
         headers: {
@@ -723,7 +723,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       perplexityKey = getRandomKeyFromMultiKey(perplexityKey);
 
       if (!perplexityKey || !perplexityHost)
-        throw new Error('Missing Perplexity API Key or Host. Add it on the UI (Models Setup) or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing Perplexity API Key or Host. Add it on the UI (Models Setup) or server side (your deployment).' });
 
       if (apiPath.startsWith('/v1'))
         apiPath = apiPath.replace('/v1', '');
@@ -746,7 +746,7 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       togetherKey = getRandomKeyFromMultiKey(togetherKey);
 
       if (!togetherKey || !togetherHost)
-        throw new Error('Missing TogetherAI API Key or Host. Add it on the UI (Models Setup) or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing TogetherAI API Key or Host. Add it on the UI (Models Setup) or server side (your deployment).' });
 
       return {
         headers: {
@@ -765,7 +765,8 @@ export function openAIAccess(access: OpenAIAccessSchema, modelRefId: string | nu
       xaiKey = getRandomKeyFromMultiKey(xaiKey);
 
       if (!xaiKey)
-        throw new Error('Missing xAI API Key. Add it on the UI (Models Setup) or server side (your deployment).');
+        throw new TRPCError({ code: 'BAD_REQUEST', message: 'Missing xAI API Key. Add it on the UI (Models Setup) or server side (your deployment).' });
+
       return {
         headers: {
           'Content-Type': 'application/json',