feat(gateway): global tier provider/model defaults with catalog-backed options

src/gateway/handlers/config.ts

@@ -1,10 +1,13 @@
 import type { GatewayRequest, OutboundMessage } from '../protocol.js';
 import { makeResponse, makeError, ErrorCode } from '../protocol.js';
 import { MODEL_PROVIDERS, type Config, type ModelProvider } from '../../config/index.js';
+import type { ModelRouter, ModelTier } from '../../models/router.js';
+import { createClientFromConfig } from '../../daemon/models.js';
 
 export interface ConfigHandlerDeps {
   config: Config;
   persistConfig?: (nextConfig: Config) => Promise<void> | void;
+  modelRouter?: ModelRouter;
 }
 
 /**
@@ -313,6 +316,52 @@ const PATCHABLE_KEYS: Record<string, (config: Config, value: unknown) => boolean
     config.agents.background_models.complex_reasoning.fallback_tier = value;
     return true;
   },
+  'models.default.provider': (config, value) => {
+    if (!MODEL_PROVIDERS.includes(String(value) as ModelProvider)) {return false;}
+    config.models.default.provider = value as ModelProvider;
+    return true;
+  },
+  'models.default.model': (config, value) => {
+    if (typeof value !== 'string' || value.trim().length === 0) {return false;}
+    config.models.default.model = value.trim();
+    return true;
+  },
+  'models.fast.provider': (config, value) => {
+    if (!MODEL_PROVIDERS.includes(String(value) as ModelProvider)) {return false;}
+    config.models.fast ??= { ...config.models.default };
+    config.models.fast.provider = value as ModelProvider;
+    return true;
+  },
+  'models.fast.model': (config, value) => {
+    if (typeof value !== 'string' || value.trim().length === 0) {return false;}
+    config.models.fast ??= { ...config.models.default };
+    config.models.fast.model = value.trim();
+    return true;
+  },
+  'models.complex.provider': (config, value) => {
+    if (!MODEL_PROVIDERS.includes(String(value) as ModelProvider)) {return false;}
+    config.models.complex ??= { ...config.models.default };
+    config.models.complex.provider = value as ModelProvider;
+    return true;
+  },
+  'models.complex.model': (config, value) => {
+    if (typeof value !== 'string' || value.trim().length === 0) {return false;}
+    config.models.complex ??= { ...config.models.default };
+    config.models.complex.model = value.trim();
+    return true;
+  },
+  'models.local.provider': (config, value) => {
+    if (!MODEL_PROVIDERS.includes(String(value) as ModelProvider)) {return false;}
+    config.models.local ??= { ...config.models.default };
+    config.models.local.provider = value as ModelProvider;
+    return true;
+  },
+  'models.local.model': (config, value) => {
+    if (typeof value !== 'string' || value.trim().length === 0) {return false;}
+    config.models.local ??= { ...config.models.default };
+    config.models.local.model = value.trim();
+    return true;
+  },
   'automation.delivery_mode': (config, value) => {
     if (value !== 'shared_session' && value !== 'isolated_job' && value !== 'announce') {return false;}
     config.automation ??= {} as Config['automation'];
@@ -406,6 +455,36 @@ const PATCHABLE_KEYS: Record<string, (config: Config, value: unknown) => boolean
 };
 
 export function createConfigHandlers(deps: ConfigHandlerDeps) {
+  const syncModelRouterFromConfig = (nextConfig: Config): void => {
+    const modelRouter = deps.modelRouter;
+    if (!modelRouter) {
+      return;
+    }
+
+    const updateTier = (tier: ModelTier, cfg: Config['models']['default'] | undefined) => {
+      if (!cfg) {
+        return;
+      }
+      try {
+        const client = createClientFromConfig(cfg);
+        modelRouter.setClient(tier, client, `${cfg.provider}/${cfg.model}`);
+        modelRouter.setTierStrict(tier, false);
+      } catch (error) {
+        // Keep config.patch successful even when runtime credentials are unavailable for a selected provider.
+        console.warn(
+          `[gateway.config] Skipping runtime model router update for tier "${tier}": ${
+            error instanceof Error ? error.message : String(error)
+          }`,
+        );
+      }
+    };
+
+    updateTier('default', nextConfig.models.default);
+    updateTier('fast', nextConfig.models.fast);
+    updateTier('complex', nextConfig.models.complex);
+    updateTier('local', nextConfig.models.local);
+  };
+
   return {
     'config.get': async (request: GatewayRequest): Promise<OutboundMessage> => {
       return makeResponse(request.id, redactConfig(deps.config));
@@ -457,6 +536,7 @@ export function createConfigHandlers(deps: ConfigHandlerDeps) {
         delete (deps.config as Record<string, unknown>)[key];
       }
       Object.assign(deps.config as Record<string, unknown>, draft as Record<string, unknown>);
+      syncModelRouterFromConfig(draft);
 
       return makeResponse(request.id, { applied, rejected, persisted: Boolean(deps.persistConfig) });
     },