fix: render tool calls above text response for external providers

- Add insertChildBefore() to Box component for positional insertion
- In chat controller, insert tool_execution components before the last
  assistant message component (instead of appending after) when tools
  were executed externally
- Simplify agent-loop externalToolExecution path back to basic
  tool_execution_start/end emission
- Toolcall streaming events are filtered in the Claude Code adapter
  to prevent duplicate rendering via message_update

Result: externally-executed tool calls render above the text response,
matching the expected visual flow.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/pi-agent-core/src/agent-loop.ts

@@ -234,8 +234,9 @@ async function runLoop(
 
 			const toolResults: ToolResultMessage[] = [];
 			if (hasMoreToolCalls && config.externalToolExecution) {
-				// External execution mode: tools were handled by the provider (e.g., Claude Code SDK).
-				// Emit synthetic tool events for TUI rendering but skip local dispatch.
+				// External execution mode: tools were handled by the provider
+				// (e.g., Claude Code SDK). Emit tool_execution events for each
+				// tool call. The TUI adds these as components after the message.
 				for (const tc of toolCalls as AgentToolCall[]) {
 					stream.push({
 						type: "tool_execution_start",

packages/pi-coding-agent/src/modes/interactive/controllers/chat-controller.ts

@@ -210,7 +210,18 @@ export async function handleAgentEvent(host: InteractiveModeStateHost & {
 					host.ui,
 				);
 				component.setExpanded(host.toolOutputExpanded);
-				host.chatContainer.addChild(component);
+
+				// For external tool execution: insert tool components before the
+				// last message component so tools render above the text response.
+				// The last child is the message that just finished streaming.
+				const children = host.chatContainer.children;
+				const lastChild = children.length > 0 ? children[children.length - 1] : undefined;
+				if (lastChild instanceof AssistantMessageComponent && !host.streamingComponent) {
+					host.chatContainer.insertChildBefore(component, lastChild);
+				} else {
+					host.chatContainer.addChild(component);
+				}
+
 				host.pendingTools.set(event.toolCallId, component);
 				host.ui.requestRender();
 			}

packages/pi-tui/src/components/box.ts

@@ -31,6 +31,16 @@ export class Box implements Component {
 		this.invalidateCache();
 	}
 
+	insertChildBefore(component: Component, before: Component): void {
+		const index = this.children.indexOf(before);
+		if (index !== -1) {
+			this.children.splice(index, 0, component);
+		} else {
+			this.children.push(component);
+		}
+		this.invalidateCache();
+	}
+
 	removeChild(component: Component): void {
 		const index = this.children.indexOf(component);
 		if (index !== -1) {