feat: add fanout mixture metadata

src/fable5/dynamic-workflows.test.ts

@@ -47,6 +47,7 @@ describe("DynamicWorkflows fan-out routing", () => {
     expect(result.routeContexts[1]?.flow).toBe("planning");
     expect(result.routeContexts[2]?.flow).toBe("review");
     expect(result.iterations).toHaveLength(3);
+    expect(result.mixtureOfAgents).toEqual({ provider: "fable-fan-out", workers: 3, synthesizer: "caller-provided", maxConcurrency: 3 });
     expect(result.synthesisVerdict).toBeDefined();
   });
 });

src/fable5/dynamic-workflows.ts

@@ -45,11 +45,19 @@ export interface WorkflowDefinition {
   maxConcurrency?: number;
 }
 
+export interface MixtureOfAgentsMetadata {
+  provider: "fable-fan-out";
+  workers: number;
+  synthesizer: "caller-provided";
+  maxConcurrency: number;
+}
+
 export interface FanOutResult {
   iterations: LoopIteration[];
   routeContexts: FanOutSubtaskRouteContext[];
   synthesized: LoopIteration;
   synthesisVerdict: VerificationResult;
+  mixtureOfAgents: MixtureOfAgentsMetadata;
 }
 
 export interface AdversarialResult {
@@ -136,7 +144,18 @@ export class DynamicWorkflows {
     // Phase 3: Verify the synthesis
     const synthesisVerdict = this.verifier.verify(synthesized, task);
 
-    return { iterations, routeContexts, synthesized, synthesisVerdict };
+    return {
+      iterations,
+      routeContexts,
+      synthesized,
+      synthesisVerdict,
+      mixtureOfAgents: {
+        provider: "fable-fan-out",
+        workers: subTasks.length,
+        synthesizer: "caller-provided",
+        maxConcurrency,
+      },
+    };
   }
 
   /**