fix: integrate federation with tool execution loop

- Federation was returning directly without executing tools
- Now federation is used for initial generation (iteration 1)
- Tool execution loop still runs for all iterations
- Subsequent iterations use local swarm (for tool result processing)
- This fixes federation + tools not working together
- All 41 tests passing

src/api/chat_handlers.py

@@ -523,21 +523,14 @@ async def handle_chat_completion(
     logger.info(f"  messages={len(request.messages)}")
     logger.info(f"{'='*60}")
 
-    # Use federation if available
-    if federated_swarm is not None:
-        peers = federated_swarm.discovery.get_peers()
-        if peers:
-            logger.info(f"🌐 Using federation with {len(peers)} peer(s)...")
-            content, tool_calls, finish_reason = await _generate_with_federation(
-                federated_swarm, prompt, request.max_tokens or 1024, request.temperature or 0.7
-            )
-            return _create_response(content, tool_calls, finish_reason, prompt, request, swarm_manager)
-
-
-
     # Build conversation history
     messages = list(request.messages)
 
+    # Determine if we should use federation for generation
+    use_federation = federated_swarm is not None and len(federated_swarm.discovery.get_peers()) > 0
+    if use_federation:
+        logger.info(f"🌐 Federation available with peers")
+
     # Track thinking content for streaming (OpenCode reasoning_content)
     thinking_content: Optional[str] = None
     thinking_captured = False
@@ -551,11 +544,22 @@ async def handle_chat_completion(
         iteration += 1
         logger.info(f"--- Tool Execution Iteration {iteration} ---")
 
-        # Generate response
+        # Generate response (use federation if available)
         logger.debug(f"Generating response...")
-        response_text, tokens_generated, tps = await _generate_with_local_swarm(
-            swarm_manager, prompt, request.max_tokens or 1024, request.temperature or 0.7
-        )
+        if use_federation and iteration == 1:
+            # First iteration: use federation for consensus
+            logger.info(f"🌐 Using federation for generation...")
+            content, tool_calls, finish_reason = await _generate_with_federation(
+                federated_swarm, prompt, request.max_tokens or 1024, request.temperature or 0.7
+            )
+            response_text = content
+            tokens_generated = 0  # Will be calculated from usage if needed
+            tps = 0.0
+        else:
+            # Subsequent iterations or no federation: use local swarm
+            response_text, tokens_generated, tps = await _generate_with_local_swarm(
+                swarm_manager, prompt, request.max_tokens or 1024, request.temperature or 0.7
+            )
 
         logger.info(f"Generated response ({len(response_text)} chars, {tokens_generated} tokens)")
         logger.debug(f"Response: {response_text[:200]}...")