feat(agent): add controlled task execution

src/runtime/opencode.ts

@@ -93,6 +93,22 @@ export class OpencodeRuntimeAdapter {
     return requireData(response.data, "global.health");
   }
 
+  async resolveAvailableModel(preferredModelIds: string[]): Promise<string> {
+    const client = await this.ensureClient();
+    const response = await client.config.providers({});
+    const configured = requireData(response.data, "config.providers");
+    const available = new Set(
+      configured.providers.flatMap((provider) =>
+        Object.keys(provider.models).map((modelId) => `${provider.id}/${modelId}`),
+      ),
+    );
+    const selected = preferredModelIds.find((modelId) => available.has(modelId));
+    if (!selected) {
+      throw new Error("no configured operational task model is available from OpenCode");
+    }
+    return selected;
+  }
+
   async warmup(): Promise<void> {
     const client = await this.ensureClient();
     const healthStartedAt = Date.now();

src/runtime/sessionContext.ts

@@ -10,6 +10,8 @@ export type RuntimeSessionContext = {
   sessionId: string;
   traceId: string;
   capabilities?: string[];
+  purpose?: "ordinary_chat" | "task_execution" | "task_collaboration";
+  taskId?: string;
 };
 
 const contexts = new Map<string, RuntimeSessionContext>();