feat(routing): honor models.for via metadata modelFor

src/daemon/routing.ts

@@ -44,6 +44,34 @@ function buildProviderConfigMap(config: Config): Partial<Record<ModelProvider, M
   return providerConfigs;
 }
 
+function tierFromUseCase(config: Config, useCaseRaw: unknown): ModelTier | undefined {
+  if (typeof useCaseRaw !== 'string') {
+    return undefined;
+  }
+  const normalized = useCaseRaw.trim().toLowerCase();
+  if (!normalized) {
+    return undefined;
+  }
+
+  const mappings: Array<{ tier: ModelTier; tags: string[] | undefined }> = [
+    { tier: 'fast', tags: config.models.fast?.for },
+    { tier: 'default', tags: config.models.default.for },
+    { tier: 'complex', tags: config.models.complex?.for },
+    { tier: 'local', tags: config.models.local?.for },
+  ];
+
+  for (const { tier, tags } of mappings) {
+    if (!tags || tags.length === 0) {
+      continue;
+    }
+    if (tags.some((tag) => tag.trim().toLowerCase() === normalized)) {
+      return tier;
+    }
+  }
+
+  return undefined;
+}
+
 /**
  * Create the unified message handler for the channel registry.
  * Each channel+sender pair gets its own AgentOrchestrator backed by a persistent session.
@@ -83,6 +111,7 @@ export function createMessageRouter(deps: {
 
     // Cron job tier wins over agent config tier
     const tierFromMetadata = metadata?.modelTier as ModelTier | undefined;
+    const tierFromUseCaseMetadata = tierFromUseCase(deps.config, metadata?.modelFor);
 
     // Include agent config name in cache key so different agents aren't shared
     let skillOverride = metadata?.skillOverride as string | undefined;
@@ -100,8 +129,9 @@ export function createMessageRouter(deps: {
     // Read per-session model tier override (persisted in SQLite)
     const sessionTierOverride = session.getConfig('modelTier') as ModelTier | undefined;
 
-    // Resolution chain: metadata (cron) → session override → agent config → global default
+    // Resolution chain: metadata (explicit tier) → metadata modelFor -> session override -> agent config -> global default
     const effectiveTier = tierFromMetadata
+      ?? tierFromUseCaseMetadata
       ?? sessionTierOverride
       ?? agentConfig?.modelTier
       ?? deps.config.agents.primary_tier
@@ -766,9 +796,12 @@ export function createMessageRouter(deps: {
       let effectiveTier: string = deps.config.agents.primary_tier ?? 'default';
       const session = deps.sessionManager.getSession(msg.channel, msg.senderId);
       const sessionTierOverride = session.getConfig('modelTier');
+      const tierFromUseCaseMetadata = tierFromUseCase(deps.config, msg.metadata?.modelFor);
 
       if (msg.metadata?.modelTier) {
         effectiveTier = msg.metadata.modelTier as string;
+      } else if (tierFromUseCaseMetadata) {
+        effectiveTier = tierFromUseCaseMetadata;
       } else if (sessionTierOverride) {
         effectiveTier = sessionTierOverride;
       } else if (deps.agentRouter && deps.agentConfigRegistry) {