🤖 feat: use couponCode as the only mux-gateway config field (#899)

Simplifies mux-gateway configuration to use only `couponCode` field.

## Changes
- Add mux-gateway to `/providers set` command suggestions
- Replace `voucher` with `couponCode` across UI, schema, and backend
- Backwards compatible: falls back to legacy `voucher` field if present

## Usage
```
/providers set mux-gateway couponCode <value>
```

_Generated with `mux`_

Author: ibetitsmike

src/browser/components/Settings/sections/ProvidersSection.tsx

@@ -46,9 +46,11 @@ function getProviderFields(provider: ProviderName): FieldConfig[] {
     ];
   }
 
-  // Mux Gateway only needs voucher
+  // Mux Gateway only needs couponCode
   if (provider === "mux-gateway") {
-    return [{ key: "voucher", label: "Voucher", placeholder: "Enter voucher", type: "secret" }];
+    return [
+      { key: "couponCode", label: "Coupon Code", placeholder: "Enter coupon code", type: "secret" },
+    ];
   }
 
   // Default for most providers
@@ -102,8 +104,8 @@ export function ProvidersSection() {
       updateOptimistically(provider, { apiKeySet: editValue !== "" });
     } else if (field === "baseUrl") {
       updateOptimistically(provider, { baseUrl: editValue || undefined });
-    } else if (field === "voucher") {
-      updateOptimistically(provider, { voucherSet: editValue !== "" });
+    } else if (field === "couponCode") {
+      updateOptimistically(provider, { couponCodeSet: editValue !== "" });
     }
 
     setEditingField(null);
@@ -122,8 +124,8 @@ export function ProvidersSection() {
         updateOptimistically(provider, { apiKeySet: false });
       } else if (field === "baseUrl") {
         updateOptimistically(provider, { baseUrl: undefined });
-      } else if (field === "voucher") {
-        updateOptimistically(provider, { voucherSet: false });
+      } else if (field === "couponCode") {
+        updateOptimistically(provider, { couponCodeSet: false });
       }
 
       // Save in background
@@ -142,9 +144,9 @@ export function ProvidersSection() {
       return !!(aws.region ?? aws.bearerTokenSet ?? aws.accessKeyIdSet ?? aws.secretAccessKeySet);
     }
 
-    // For Mux Gateway, check voucherSet
+    // For Mux Gateway, check couponCodeSet
     if (provider === "mux-gateway") {
-      return providerConfig.voucherSet ?? false;
+      return providerConfig.couponCodeSet ?? false;
     }
 
     // For other providers, check apiKeySet
@@ -172,8 +174,8 @@ export function ProvidersSection() {
     if (fieldConfig.type === "secret") {
       // For apiKey, we have apiKeySet from the sanitized config
       if (field === "apiKey") return providerConfig.apiKeySet ?? false;
-      // For voucher (mux-gateway), check voucherSet
-      if (field === "voucher") return providerConfig.voucherSet ?? false;
+      // For couponCode (mux-gateway), check couponCodeSet
+      if (field === "couponCode") return providerConfig.couponCodeSet ?? false;
 
       // For AWS secrets, check the aws nested object
       if (provider === "bedrock" && providerConfig.aws) {

src/browser/utils/slashCommands/registry.ts

@@ -60,6 +60,10 @@ const DEFAULT_PROVIDER_NAMES: SuggestionDefinition[] = [
     key: "bedrock",
     description: "Amazon Bedrock provider (AWS)",
   },
+  {
+    key: "mux-gateway",
+    description: "Mux Gateway provider",
+  },
 ];
 
 const DEFAULT_PROVIDER_KEYS: Record<string, SuggestionDefinition[]> = {
@@ -111,6 +115,12 @@ const DEFAULT_PROVIDER_KEYS: Record<string, SuggestionDefinition[]> = {
       description: "AWS Secret Access Key (use with accessKeyId)",
     },
   ],
+  "mux-gateway": [
+    {
+      key: "couponCode",
+      description: "Coupon code for Mux Gateway access",
+    },
+  ],
   default: [
     {
       key: "apiKey",

src/common/orpc/schemas/api.test.ts

@@ -65,16 +65,16 @@ describe("ProviderConfigInfoSchema conformance", () => {
     expect(parsed.aws).toEqual(full.aws);
   });
 
-  it("preserves all ProviderConfigInfo fields (with voucherSet)", () => {
+  it("preserves all ProviderConfigInfo fields (with couponCodeSet)", () => {
     const full: ProviderConfigInfo = {
       apiKeySet: true,
-      voucherSet: true,
+      couponCodeSet: true,
     };
 
     const parsed = ProviderConfigInfoSchema.parse(full);
 
     expect(parsed).toEqual(full);
-    expect(parsed.voucherSet).toBe(true);
+    expect(parsed.couponCodeSet).toBe(true);
   });
 
   it("preserves all ProviderConfigInfo fields (full object with all optional fields)", () => {
@@ -89,7 +89,7 @@ describe("ProviderConfigInfoSchema conformance", () => {
         accessKeyIdSet: true,
         secretAccessKeySet: true,
       },
-      voucherSet: true,
+      couponCodeSet: true,
     };
 
     const parsed = ProviderConfigInfoSchema.parse(full);
@@ -102,7 +102,7 @@ describe("ProviderConfigInfoSchema conformance", () => {
     expect(parsed.baseUrl).toBe(full.baseUrl);
     expect(parsed.models).toEqual(full.models);
     expect(parsed.aws).toEqual(full.aws);
-    expect(parsed.voucherSet).toBe(full.voucherSet);
+    expect(parsed.couponCodeSet).toBe(full.couponCodeSet);
   });
 
   it("preserves ProvidersConfigMap with multiple providers", () => {
@@ -122,7 +122,7 @@ describe("ProviderConfigInfoSchema conformance", () => {
       },
       "mux-gateway": {
         apiKeySet: false,
-        voucherSet: true,
+        couponCodeSet: true,
         models: ["anthropic/claude-sonnet-4-5"],
       },
     };

src/common/orpc/schemas/api.ts

@@ -49,7 +49,7 @@ export const ProviderConfigInfoSchema = z.object({
   /** AWS-specific fields (only present for bedrock provider) */
   aws: AWSCredentialStatusSchema.optional(),
   /** Mux Gateway-specific fields */
-  voucherSet: z.boolean().optional(),
+  couponCodeSet: z.boolean().optional(),
 });
 
 export const ProvidersConfigMapSchema = z.record(z.string(), ProviderConfigInfoSchema);

src/node/services/aiService.ts

@@ -751,9 +751,9 @@ export class AIService extends EventEmitter {
 
       // Handle Mux Gateway provider
       if (providerName === "mux-gateway") {
-        // Mux Gateway uses voucher as the API key (fallback to legacy couponCode)
-        const voucher = providerConfig.voucher ?? providerConfig.couponCode;
-        if (typeof voucher !== "string" || !voucher) {
+        // Mux Gateway uses couponCode as the API key (fallback to legacy voucher)
+        const couponCode = providerConfig.couponCode ?? providerConfig.voucher;
+        if (typeof couponCode !== "string" || !couponCode) {
           return Err({
             type: "api_key_not_found",
             provider: providerName,
@@ -773,7 +773,7 @@ export class AIService extends EventEmitter {
         const gatewayBaseURL =
           providerConfig.baseURL ?? "https://gateway.mux.coder.com/api/v1/ai-gateway/v1/ai";
         const gateway = createGateway({
-          apiKey: voucher,
+          apiKey: couponCode,
           baseURL: gatewayBaseURL,
           fetch: fetchWithCacheControl,
         });

src/node/services/providerService.ts

@@ -73,9 +73,10 @@ export class ProviderService {
         };
       }
 
-      // Mux Gateway-specific fields
+      // Mux Gateway-specific fields (check couponCode first, fallback to legacy voucher)
       if (provider === "mux-gateway") {
-        providerInfo.voucherSet = !!(config as { voucher?: string }).voucher;
+        const muxConfig = config as { couponCode?: string; voucher?: string };
+        providerInfo.couponCodeSet = !!(muxConfig.couponCode ?? muxConfig.voucher);
       }
 
       result[provider] = providerInfo;
@@ -111,13 +112,13 @@ export class ProviderService {
       // Load current providers config or create empty
       const providersConfig = this.config.loadProvidersConfig() ?? {};
 
-      // Track if this is first time setting voucher for mux-gateway
-      const isFirstMuxGatewayVoucher =
+      // Track if this is first time setting couponCode for mux-gateway
+      const isFirstMuxGatewayCoupon =
         provider === "mux-gateway" &&
         keyPath.length === 1 &&
-        keyPath[0] === "voucher" &&
+        keyPath[0] === "couponCode" &&
         value !== "" &&
-        !providersConfig[provider]?.voucher;
+        !providersConfig[provider]?.couponCode;
 
       // Ensure provider exists
       if (!providersConfig[provider]) {
@@ -145,7 +146,7 @@ export class ProviderService {
       }
 
       // Add default models when setting up mux-gateway for the first time
-      if (isFirstMuxGatewayVoucher) {
+      if (isFirstMuxGatewayCoupon) {
         const providerConfig = providersConfig[provider] as Record<string, unknown>;
         if (!providerConfig.models || (providerConfig.models as string[]).length === 0) {
           providerConfig.models = [