diff --git a/messages/en-US.json b/messages/en-US.json
index fa9202b2f..257c56c42 100644
--- a/messages/en-US.json
+++ b/messages/en-US.json
@@ -1652,7 +1652,7 @@
     "aiProviderNetworkSettings": "Network Settings",
     "aiProviderNetworkSettingsDescription": "Choose how traffic reaches this provider",
     "aiProviderAuthSettings": "Authentication",
-    "aiProviderAuthSettingsDescription": "Credentials used for both upstream URL and Pangolin target routing",
+    "aiProviderAuthSettingsDescription": "Configure how this provider authenticates requests to its upstream URL",
     "aiProviderType": "Provider Type",
     "aiProviderTypeSearch": "Search providers...",
     "aiProviderTypeNotFound": "No provider type found",
@@ -1683,6 +1683,10 @@
     "aiProviderApiKeyLastChars": "API Key",
     "aiProviderAuthType": "Auth Type",
     "aiProviderAuthTypeBearer": "Bearer",
+    "aiProviderAuthTypeXApiKey": "x-api-key",
+    "aiProviderAuthTypeXGoogApiKey": "x-goog-api-key",
+    "aiProviderAuthTypeHec": "Splunk HEC",
+    "aiProviderAuthTypeCfAigAuthorization": "Cloudflare AI Gateway",
     "aiProviderAuthTypeDescription": "How the upstream API authenticates requests",
     "aiProviderRoutingMode": "Routing Mode",
     "aiProviderRoutingModeDescription": "Send traffic to an upstream URL or to HTTP targets on your sites",
diff --git a/server/db/pg/schema/schema.ts b/server/db/pg/schema/schema.ts
index 868b2a121..7883345da 100644
--- a/server/db/pg/schema/schema.ts
+++ b/server/db/pg/schema/schema.ts
@@ -1644,7 +1644,15 @@ export const aiProviders = pgTable("aiProviders", {
     upstreamUrl: text("upstreamUrl"),
     apiKey: text("apiKey"),
     apiKeyLastChars: varchar("apiKeyLastChars"),
-    authType: varchar("authType").$type<"bearer">(),
+    authType: varchar("authType")
+        .$type<
+            | "bearer"
+            | "x-api-key"
+            | "x-goog-api-key"
+            | "hec"
+            | "cf-aig-authorization"
+        >()
+        .notNull(),
     routingMode: varchar("routingMode")
         .$type<"url" | "target">()
         .notNull()
diff --git a/server/db/sqlite/schema/schema.ts b/server/db/sqlite/schema/schema.ts
index 8af639238..e586c4e02 100644
--- a/server/db/sqlite/schema/schema.ts
+++ b/server/db/sqlite/schema/schema.ts
@@ -1626,7 +1626,15 @@ export const aiProviders = sqliteTable("aiProviders", {
     upstreamUrl: text("upstreamUrl"),
     apiKey: text("apiKey"),
     apiKeyLastChars: text("apiKeyLastChars"),
-    authType: text("authType").$type<"bearer">(),
+    authType: text("authType")
+        .$type<
+            | "bearer"
+            | "x-api-key"
+            | "x-goog-api-key"
+            | "hec"
+            | "cf-aig-authorization"
+        >()
+        .notNull(),
     routingMode: text("routingMode")
         .$type<"url" | "target">()
         .notNull()
diff --git a/server/lib/aiProviderDefaults.ts b/server/lib/aiProviderDefaults.ts
index 6cfb816b7..d803e7613 100644
--- a/server/lib/aiProviderDefaults.ts
+++ b/server/lib/aiProviderDefaults.ts
@@ -9,7 +9,15 @@ export type AiProviderType =
     | "vercelAiGateway"
     | "custom";
 
-export type AiProviderAuthType = "bearer";
+export const AI_PROVIDER_AUTH_TYPES = [
+    "bearer",
+    "x-api-key",
+    "x-goog-api-key",
+    "hec",
+    "cf-aig-authorization"
+] as const;
+
+export type AiProviderAuthType = (typeof AI_PROVIDER_AUTH_TYPES)[number];
 export type AiBudgetUnit = "usd" | "tokens";
 export type AiProviderRoutingMode = "url" | "target";
 
@@ -28,11 +36,11 @@ export const AI_PROVIDER_DEFAULTS: Record<
     },
     anthropic: {
         upstreamUrl: "https://api.anthropic.com",
-        authType: "bearer"
+        authType: "x-api-key"
     },
     googleGemini: {
         upstreamUrl: "https://generativelanguage.googleapis.com/v1beta/openai/",
-        authType: "bearer"
+        authType: "x-goog-api-key"
     },
     vertexAi: {
         upstreamUrl: null,
@@ -56,6 +64,13 @@ export const AI_PROVIDER_DEFAULTS: Record<
     }
 };
 
+const CONFLICTING_AUTH_HEADERS = [
+    "authorization",
+    "x-api-key",
+    "x-goog-api-key",
+    "cf-aig-authorization"
+] as const;
+
 export function providerRequiresUpstreamUrl(
     type: AiProviderType,
     routingMode: AiProviderRoutingMode = "url"
@@ -69,17 +84,18 @@ export function providerRequiresUpstreamUrl(
     return AI_PROVIDER_DEFAULTS[type].upstreamUrl === null;
 }
 
-export function resolveAiProviderConfig(input: {
+export function resolveAiProviderCreateFields(input: {
     type: AiProviderType;
-    upstreamUrl: string | null;
-    authType: AiProviderAuthType | null;
+    upstreamUrl?: string | null;
+    authType?: AiProviderAuthType | null;
     routingMode?: AiProviderRoutingMode | null;
 }): {
     upstreamUrl: string | null;
-    authType: AiProviderAuthType | null;
+    authType: AiProviderAuthType;
     routingMode: AiProviderRoutingMode;
 } {
-    const routingMode = input.routingMode ?? "url";
+    const routingMode =
+        input.type === "custom" ? (input.routingMode ?? "url") : "url";
 
     if (routingMode === "target") {
         return {
@@ -91,8 +107,8 @@ export function resolveAiProviderConfig(input: {
 
     if (input.type === "custom") {
         return {
-            upstreamUrl: input.upstreamUrl,
-            authType: input.authType,
+            upstreamUrl: input.upstreamUrl ?? null,
+            authType: input.authType ?? "bearer",
             routingMode
         };
     }
@@ -100,7 +116,43 @@ export function resolveAiProviderConfig(input: {
     const defaults = AI_PROVIDER_DEFAULTS[input.type];
     return {
         upstreamUrl: input.upstreamUrl ?? defaults.upstreamUrl,
-        authType: input.authType ?? defaults.authType,
+        authType: defaults.authType,
         routingMode
     };
 }
+
+/**
+ * Strip inbound client auth headers, then set the provider auth header
+ * for the given authType.
+ */
+export function applyAiProviderAuthHeaders(
+    headers: Record<string, string>,
+    authType: AiProviderAuthType,
+    apiKey: string
+): void {
+    for (const name of CONFLICTING_AUTH_HEADERS) {
+        for (const key of Object.keys(headers)) {
+            if (key.toLowerCase() === name) {
+                delete headers[key];
+            }
+        }
+    }
+
+    switch (authType) {
+        case "bearer":
+            headers["Authorization"] = `Bearer ${apiKey}`;
+            break;
+        case "x-api-key":
+            headers["x-api-key"] = apiKey;
+            break;
+        case "x-goog-api-key":
+            headers["x-goog-api-key"] = apiKey;
+            break;
+        case "hec":
+            headers["Authorization"] = `Splunk ${apiKey}`;
+            break;
+        case "cf-aig-authorization":
+            headers["cf-aig-authorization"] = `Bearer ${apiKey}`;
+            break;
+    }
+}
diff --git a/server/routers/aiGateway/chatCompletions.ts b/server/routers/aiGateway/chatCompletions.ts
index 2f1bfc451..e1bb8bbc9 100644
--- a/server/routers/aiGateway/chatCompletions.ts
+++ b/server/routers/aiGateway/chatCompletions.ts
@@ -19,9 +19,7 @@ import config from "@server/lib/config";
 import { decrypt } from "@server/lib/crypto";
 import {
     AiProviderAuthType,
-    AiProviderRoutingMode,
-    AiProviderType,
-    resolveAiProviderConfig
+    applyAiProviderAuthHeaders
 } from "@server/lib/aiProviderDefaults";
 import {
     SESSION_COOKIE_NAME,
@@ -499,12 +497,8 @@ export async function chatCompletions(
         const secret = config.getRawConfig().server.secret!;
         const apiKey = decrypt(provider.apiKey, secret);
 
-        const { upstreamUrl, authType } = resolveAiProviderConfig({
-            type: provider.type as AiProviderType,
-            upstreamUrl: provider.upstreamUrl,
-            authType: provider.authType as AiProviderAuthType | null,
-            routingMode: provider.routingMode as AiProviderRoutingMode | null
-        });
+        const upstreamUrl = provider.upstreamUrl;
+        const authType = provider.authType as AiProviderAuthType;
 
         if (!upstreamUrl) {
             return res.status(HttpCode.INTERNAL_SERVER_ERROR).json({
@@ -541,8 +535,7 @@ export async function chatCompletions(
             }
             headers[key] = Array.isArray(value) ? value.join(", ") : value;
         }
-        // TODO: temporary hardcoded auth for testing; restore bearer from authType
-        headers["x-api-key"] = apiKey;
+        applyAiProviderAuthHeaders(headers, authType, apiKey);
 
         // No dedicated per-request TLS agent is wired up (no extra deps for
         // this v1 gateway) - toggle the process-wide Node TLS check instead.
diff --git a/server/routers/aiProvider/createAiProvider.ts b/server/routers/aiProvider/createAiProvider.ts
index 6fb3f395a..6188601a3 100644
--- a/server/routers/aiProvider/createAiProvider.ts
+++ b/server/routers/aiProvider/createAiProvider.ts
@@ -9,6 +9,7 @@ import { fromError } from "zod-validation-error";
 import { OpenAPITags, registry } from "@server/openApi";
 import { encrypt } from "@server/lib/crypto";
 import config from "@server/lib/config";
+import { resolveAiProviderCreateFields } from "@server/lib/aiProviderDefaults";
 import type { CreateOrEditAiProviderResponse } from "@server/routers/aiProvider/types";
 import { toPublicAiProvider } from "@server/routers/aiProvider/types";
 import {
@@ -28,7 +29,7 @@ const bodySchema = z
         type: aiProviderTypeSchema,
         upstreamUrl: z.url().optional().nullable(),
         apiKey: z.string().optional(),
-        authType: aiAuthTypeSchema.optional().nullable(),
+        authType: aiAuthTypeSchema.optional(),
         routingMode: aiRoutingModeSchema.optional(),
         skipTlsVerification: z.boolean().optional(),
         enabled: z.boolean().optional()
@@ -101,8 +102,12 @@ export async function createAiProvider(
         const encryptedApiKey = apiKey ? encrypt(apiKey, key) : null;
         const apiKeyLastChars = apiKey ? apiKey.slice(-4) : null;
         const now = Date.now();
-        const resolvedRoutingMode =
-            type === "custom" ? (routingMode ?? "url") : "url";
+        const resolved = resolveAiProviderCreateFields({
+            type,
+            upstreamUrl,
+            authType,
+            routingMode
+        });
 
         const [provider] = await db
             .insert(aiProviders)
@@ -110,14 +115,11 @@ export async function createAiProvider(
                 orgId,
                 name,
                 type,
-                upstreamUrl:
-                    resolvedRoutingMode === "target"
-                        ? null
-                        : (upstreamUrl ?? null),
+                upstreamUrl: resolved.upstreamUrl,
                 apiKey: encryptedApiKey,
                 apiKeyLastChars,
-                authType: authType ?? null,
-                routingMode: resolvedRoutingMode,
+                authType: resolved.authType,
+                routingMode: resolved.routingMode,
                 skipTlsVerification: skipTlsVerification ?? false,
                 enabled: enabled ?? true,
                 createdAt: now,
diff --git a/server/routers/aiProvider/types.ts b/server/routers/aiProvider/types.ts
index 3fa966785..7ac492056 100644
--- a/server/routers/aiProvider/types.ts
+++ b/server/routers/aiProvider/types.ts
@@ -1,11 +1,6 @@
 import type { AiModel, AiProvider } from "@server/db";
 import type { PaginatedResponse } from "@server/types/Pagination";
-import {
-    resolveAiProviderConfig,
-    type AiProviderAuthType,
-    type AiProviderRoutingMode,
-    type AiProviderType
-} from "@server/lib/aiProviderDefaults";
+import type { AiProviderAuthType } from "@server/lib/aiProviderDefaults";
 import { decrypt } from "@server/lib/crypto";
 import config from "@server/lib/config";
 
@@ -13,7 +8,7 @@ export type AiProviderPublic = Omit<AiProvider, "apiKey"> & {
     /** Decrypted API key. Only included on get/create/update of a single provider. */
     apiKey?: string | null;
     effectiveUpstreamUrl: string | null;
-    effectiveAuthType: AiProviderAuthType | null;
+    effectiveAuthType: AiProviderAuthType;
 };
 
 export type ListAiProvidersResponse = PaginatedResponse<{
@@ -45,12 +40,6 @@ export function toPublicAiProvider(
     options?: { includeApiKey?: boolean }
 ): AiProviderPublic {
     const { apiKey: encryptedApiKey, ...rest } = provider;
-    const resolved = resolveAiProviderConfig({
-        type: provider.type as AiProviderType,
-        upstreamUrl: provider.upstreamUrl,
-        authType: provider.authType as AiProviderAuthType | null,
-        routingMode: provider.routingMode as AiProviderRoutingMode | null
-    });
 
     let apiKey: string | null | undefined;
     if (options?.includeApiKey) {
@@ -67,7 +56,7 @@ export function toPublicAiProvider(
     return {
         ...rest,
         ...(options?.includeApiKey ? { apiKey } : {}),
-        effectiveUpstreamUrl: resolved.upstreamUrl,
-        effectiveAuthType: resolved.authType
+        effectiveUpstreamUrl: provider.upstreamUrl,
+        effectiveAuthType: provider.authType as AiProviderAuthType
     };
 }
diff --git a/server/routers/aiProvider/updateAiProvider.ts b/server/routers/aiProvider/updateAiProvider.ts
index 35e27fba2..82224c28b 100644
--- a/server/routers/aiProvider/updateAiProvider.ts
+++ b/server/routers/aiProvider/updateAiProvider.ts
@@ -19,6 +19,7 @@ import {
     refineProviderUpstreamFields
 } from "@server/routers/aiProvider/validation";
 import type {
+    AiProviderAuthType,
     AiProviderRoutingMode,
     AiProviderType
 } from "@server/lib/aiProviderDefaults";
@@ -31,7 +32,7 @@ const bodySchema = z.strictObject({
     name: z.string().nonempty().optional(),
     upstreamUrl: z.url().optional().nullable(),
     apiKey: z.string().optional(),
-    authType: aiAuthTypeSchema.optional().nullable(),
+    authType: aiAuthTypeSchema.optional(),
     routingMode: aiRoutingModeSchema.optional(),
     skipTlsVerification: z.boolean().optional(),
     enabled: z.boolean().optional()
@@ -116,17 +117,16 @@ export async function updateAiProvider(
             body.upstreamUrl !== undefined
                 ? body.upstreamUrl
                 : existing.upstreamUrl;
-        const nextAuthType =
+        const nextAuthType: AiProviderAuthType =
             body.authType !== undefined
                 ? body.authType
-                : (existing.authType ??
-                  (providerType === "custom" ? "bearer" : null));
+                : (existing.authType as AiProviderAuthType);
 
         const validation = z
             .object({
                 type: aiProviderTypeSchema,
                 upstreamUrl: z.string().nullable().optional(),
-                authType: aiAuthTypeSchema.nullable().optional(),
+                authType: aiAuthTypeSchema,
                 routingMode: aiRoutingModeSchema.optional()
             })
             .superRefine((data, ctx) => refineProviderUpstreamFields(data, ctx))
@@ -167,13 +167,6 @@ export async function updateAiProvider(
         }
         if (body.authType !== undefined) {
             updateData.authType = body.authType;
-        } else if (
-            providerType === "custom" &&
-            !existing.authType &&
-            nextAuthType
-        ) {
-            // Backfill required authType for custom providers created without one
-            updateData.authType = nextAuthType;
         }
 
         if (body.apiKey !== undefined) {
diff --git a/server/routers/aiProvider/validation.ts b/server/routers/aiProvider/validation.ts
index a5e2aa962..42476c710 100644
--- a/server/routers/aiProvider/validation.ts
+++ b/server/routers/aiProvider/validation.ts
@@ -1,6 +1,8 @@
 import { z } from "zod";
 import {
+    AI_PROVIDER_AUTH_TYPES,
     providerRequiresUpstreamUrl,
+    type AiProviderAuthType,
     type AiProviderRoutingMode,
     type AiProviderType
 } from "@server/lib/aiProviderDefaults";
@@ -17,7 +19,7 @@ export const aiProviderTypeSchema = z.enum([
     "custom"
 ]);
 
-export const aiAuthTypeSchema = z.enum(["bearer"]);
+export const aiAuthTypeSchema = z.enum(AI_PROVIDER_AUTH_TYPES);
 
 export const aiRoutingModeSchema = z.enum(["url", "target"]);
 
@@ -25,7 +27,7 @@ export function refineProviderUpstreamFields(
     data: {
         type: AiProviderType;
         upstreamUrl?: string | null;
-        authType?: "bearer" | null;
+        authType?: AiProviderAuthType | null;
         routingMode?: AiProviderRoutingMode | null;
     },
     ctx: z.RefinementCtx
diff --git a/src/app/[orgId]/settings/ai-providers/[providerId]/authentication/page.tsx b/src/app/[orgId]/settings/ai-providers/[providerId]/authentication/page.tsx
index 02d1d2142..264e6b252 100644
--- a/src/app/[orgId]/settings/ai-providers/[providerId]/authentication/page.tsx
+++ b/src/app/[orgId]/settings/ai-providers/[providerId]/authentication/page.tsx
@@ -40,7 +40,10 @@ import {
     type AiProviderFormValues
 } from "@app/lib/aiProviderFormSchema";
 import { zodResolver } from "@hookform/resolvers/zod";
-import type { AiProviderType } from "@server/lib/aiProviderDefaults";
+import type {
+    AiProviderAuthType,
+    AiProviderType
+} from "@server/lib/aiProviderDefaults";
 import type { CreateOrEditAiProviderResponse } from "@server/routers/aiProvider/types";
 import type { AxiosResponse } from "axios";
 import { useTranslations } from "next-intl";
@@ -63,7 +66,7 @@ export default function AiProviderAuthenticationPage() {
             type: provider.type as AiProviderType,
             upstreamUrl: provider.upstreamUrl ?? "",
             apiKey: provider.apiKey ?? "",
-            authType: (provider.authType as "bearer" | null) ?? "bearer",
+            authType: (provider.authType as AiProviderAuthType) ?? "bearer",
             routingMode: (provider.routingMode as "url" | "target") ?? "url",
             skipTlsVerification: provider.skipTlsVerification,
             enabled: provider.enabled
@@ -91,7 +94,7 @@ export default function AiProviderAuthenticationPage() {
                 type: updated.type as AiProviderType,
                 upstreamUrl: updated.upstreamUrl ?? "",
                 apiKey: updated.apiKey ?? "",
-                authType: (updated.authType as "bearer" | null) ?? "bearer",
+                authType: (updated.authType as AiProviderAuthType) ?? "bearer",
                 routingMode: (updated.routingMode as "url" | "target") ?? "url",
                 skipTlsVerification: updated.skipTlsVerification,
                 enabled: updated.enabled
@@ -164,6 +167,26 @@ export default function AiProviderAuthenticationPage() {
                                                                         "aiProviderAuthTypeBearer"
                                                                     )}
                                                                 </SelectItem>
+                                                                <SelectItem value="x-api-key">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeXApiKey"
+                                                                    )}
+                                                                </SelectItem>
+                                                                <SelectItem value="x-goog-api-key">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeXGoogApiKey"
+                                                                    )}
+                                                                </SelectItem>
+                                                                <SelectItem value="hec">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeHec"
+                                                                    )}
+                                                                </SelectItem>
+                                                                <SelectItem value="cf-aig-authorization">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeCfAigAuthorization"
+                                                                    )}
+                                                                </SelectItem>
                                                             </SelectContent>
                                                         </Select>
                                                         <FormDescription>
diff --git a/src/app/[orgId]/settings/ai-providers/[providerId]/network/page.tsx b/src/app/[orgId]/settings/ai-providers/[providerId]/network/page.tsx
index fbe9669cf..270ba3c68 100644
--- a/src/app/[orgId]/settings/ai-providers/[providerId]/network/page.tsx
+++ b/src/app/[orgId]/settings/ai-providers/[providerId]/network/page.tsx
@@ -45,7 +45,10 @@ import {
 } from "@app/lib/aiProviderFormSchema";
 import { aiProviderQueries } from "@app/lib/queries";
 import { zodResolver } from "@hookform/resolvers/zod";
-import type { AiProviderType } from "@server/lib/aiProviderDefaults";
+import type {
+    AiProviderAuthType,
+    AiProviderType
+} from "@server/lib/aiProviderDefaults";
 import type { CreateOrEditAiProviderResponse } from "@server/routers/aiProvider/types";
 import { useQuery } from "@tanstack/react-query";
 import type { AxiosResponse } from "axios";
@@ -72,7 +75,7 @@ export default function AiProviderNetworkPage() {
             type: provider.type as AiProviderType,
             upstreamUrl: provider.upstreamUrl ?? "",
             apiKey: "",
-            authType: (provider.authType as "bearer" | null) ?? "bearer",
+            authType: (provider.authType as AiProviderAuthType) ?? "bearer",
             routingMode: (provider.routingMode as "url" | "target") ?? "url",
             skipTlsVerification: provider.skipTlsVerification,
             enabled: provider.enabled
@@ -115,7 +118,7 @@ export default function AiProviderNetworkPage() {
                 type: updated.type as AiProviderType,
                 upstreamUrl: updated.upstreamUrl ?? "",
                 apiKey: "",
-                authType: (updated.authType as "bearer" | null) ?? "bearer",
+                authType: (updated.authType as AiProviderAuthType) ?? "bearer",
                 routingMode: (updated.routingMode as "url" | "target") ?? "url",
                 skipTlsVerification: updated.skipTlsVerification,
                 enabled: updated.enabled
diff --git a/src/app/[orgId]/settings/ai-providers/create/page.tsx b/src/app/[orgId]/settings/ai-providers/create/page.tsx
index b84462153..5ad4c4ec7 100644
--- a/src/app/[orgId]/settings/ai-providers/create/page.tsx
+++ b/src/app/[orgId]/settings/ai-providers/create/page.tsx
@@ -527,6 +527,26 @@ export default function CreateAiProviderPage() {
                                                                         "aiProviderAuthTypeBearer"
                                                                     )}
                                                                 </SelectItem>
+                                                                <SelectItem value="x-api-key">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeXApiKey"
+                                                                    )}
+                                                                </SelectItem>
+                                                                <SelectItem value="x-goog-api-key">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeXGoogApiKey"
+                                                                    )}
+                                                                </SelectItem>
+                                                                <SelectItem value="hec">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeHec"
+                                                                    )}
+                                                                </SelectItem>
+                                                                <SelectItem value="cf-aig-authorization">
+                                                                    {t(
+                                                                        "aiProviderAuthTypeCfAigAuthorization"
+                                                                    )}
+                                                                </SelectItem>
                                                             </SelectContent>
                                                         </Select>
                                                         <FormDescription>
diff --git a/src/lib/aiProviderFormSchema.ts b/src/lib/aiProviderFormSchema.ts
index 26245620c..8eb038fba 100644
--- a/src/lib/aiProviderFormSchema.ts
+++ b/src/lib/aiProviderFormSchema.ts
@@ -1,5 +1,6 @@
 import { z } from "zod";
 import {
+    AI_PROVIDER_AUTH_TYPES,
     AI_PROVIDER_DEFAULTS,
     providerRequiresUpstreamUrl,
     type AiProviderType
@@ -23,7 +24,7 @@ export const aiProviderFormSchema = z
         type: z.enum(aiProviderTypeValues),
         upstreamUrl: z.string().optional().nullable(),
         apiKey: z.string().optional(),
-        authType: z.enum(["bearer"]).optional().nullable(),
+        authType: z.enum(AI_PROVIDER_AUTH_TYPES).optional().nullable(),
         routingMode: z.enum(["url", "target"]).optional(),
         skipTlsVerification: z.boolean().optional(),
         enabled: z.boolean().optional()
@@ -138,7 +139,7 @@ export function toAiProviderCreatePayload(values: AiProviderFormValues) {
         authType:
             values.type === "custom"
                 ? (values.authType ?? "bearer")
-                : (values.authType ?? undefined),
+                : undefined,
         skipTlsVerification: values.skipTlsVerification,
         enabled: values.enabled ?? true
     };
@@ -159,14 +160,14 @@ export function toAiProviderUpdatePayload(values: AiProviderFormValues) {
         name: values.name.trim(),
         routingMode: values.type === "custom" ? routingMode : "url",
         upstreamUrl,
-        authType:
-            values.type === "custom"
-                ? (values.authType ?? "bearer")
-                : (values.authType ?? null),
         skipTlsVerification: values.skipTlsVerification ?? false,
         enabled: values.enabled ?? true
     };
 
+    if (values.type === "custom") {
+        payload.authType = values.authType ?? "bearer";
+    }
+
     if (values.apiKey?.trim()) {
         payload.apiKey = values.apiKey.trim();
     }
@@ -184,11 +185,13 @@ export function toAiProviderNetworkPayload(values: AiProviderFormValues) {
 }
 
 export function toAiProviderAuthPayload(values: AiProviderFormValues) {
-    const full = toAiProviderUpdatePayload(values);
-    return {
-        authType: full.authType,
+    const payload: Record<string, unknown> = {
         ...(values.apiKey !== undefined ? { apiKey: values.apiKey.trim() } : {})
     };
+    if (values.type === "custom") {
+        payload.authType = values.authType ?? "bearer";
+    }
+    return payload;
 }
 
 export function toAiProviderConfigurationPayload(values: AiProviderFormValues) {