agent: Add reasoning token support for OpenAI reasoning models

- Extract and display reasoning tokens from both Chat Completions and Responses APIs
- Add smart preflight detection to check reasoning support per model/API (cached per agent)
- Support both reasoning_text (o1/o3) and summary_text (gpt-5) formats
- Display reasoning tokens with ⚡ symbol in console and TUI renderers
- Only send reasoning parameters to models that support them
- Fix event type from "thinking" to "reasoning" for consistency

Note: Chat Completions API only returns reasoning token counts, not content (by design).
Only Responses API exposes actual thinking/reasoning events.

packages/agent/src/renderers/console-renderer.ts

@@ -13,6 +13,7 @@ export class ConsoleRenderer implements AgentEventReceiver {
 	private lastOutputTokens = 0;
 	private lastCacheReadTokens = 0;
 	private lastCacheWriteTokens = 0;
+	private lastReasoningTokens = 0;
 
 	private startAnimation(text: string = "Thinking"): void {
 		if (this.isAnimating || !this.isTTY) return;
@@ -54,6 +55,11 @@ export class ConsoleRenderer implements AgentEventReceiver {
 			`↑${this.lastInputTokens.toLocaleString()} ↓${this.lastOutputTokens.toLocaleString()}`,
 		);
 
+		// Add reasoning tokens if present
+		if (this.lastReasoningTokens > 0) {
+			metricsText += chalk.dim(` ⚡${this.lastReasoningTokens.toLocaleString()}`);
+		}
+
 		// Add cache info if available
 		if (this.lastCacheReadTokens > 0 || this.lastCacheWriteTokens > 0) {
 			const cacheText: string[] = [];
@@ -96,7 +102,7 @@ export class ConsoleRenderer implements AgentEventReceiver {
 				this.startAnimation();
 				break;
 
-			case "thinking":
+			case "reasoning":
 				this.stopAnimation();
 				console.log(chalk.dim("[thinking]"));
 				console.log(chalk.dim(event.text));
@@ -162,6 +168,7 @@ export class ConsoleRenderer implements AgentEventReceiver {
 				this.lastOutputTokens = event.outputTokens;
 				this.lastCacheReadTokens = event.cacheReadTokens;
 				this.lastCacheWriteTokens = event.cacheWriteTokens;
+				this.lastReasoningTokens = event.reasoningTokens;
 				// Don't stop animation for this event
 				break;
 		}

packages/agent/src/renderers/tui-renderer.ts

@@ -61,6 +61,7 @@ export class TuiRenderer implements AgentEventReceiver {
 	private lastOutputTokens = 0;
 	private lastCacheReadTokens = 0;
 	private lastCacheWriteTokens = 0;
+	private lastReasoningTokens = 0;
 	private toolCallCount = 0;
 	private tokenStatusComponent: TextComponent | null = null;
 
@@ -185,7 +186,7 @@ export class TuiRenderer implements AgentEventReceiver {
 				this.statusContainer.addChild(this.currentLoadingAnimation);
 				break;
 
-			case "thinking": {
+			case "reasoning": {
 				// Show thinking in dim text
 				const thinkingContainer = new Container();
 				thinkingContainer.addChild(new TextComponent(chalk.dim("[thinking]")));
@@ -264,6 +265,7 @@ export class TuiRenderer implements AgentEventReceiver {
 				this.lastOutputTokens = event.outputTokens;
 				this.lastCacheReadTokens = event.cacheReadTokens;
 				this.lastCacheWriteTokens = event.cacheWriteTokens;
+				this.lastReasoningTokens = event.reasoningTokens;
 				this.updateTokenDisplay();
 				break;
 
@@ -291,6 +293,11 @@ export class TuiRenderer implements AgentEventReceiver {
 		// Build token display text
 		let tokenText = chalk.dim(`↑${this.lastInputTokens.toLocaleString()} ↓${this.lastOutputTokens.toLocaleString()}`);
 
+		// Add reasoning tokens if present
+		if (this.lastReasoningTokens > 0) {
+			tokenText += chalk.dim(` ⚡${this.lastReasoningTokens.toLocaleString()}`);
+		}
+
 		// Add cache info if available
 		if (this.lastCacheReadTokens > 0 || this.lastCacheWriteTokens > 0) {
 			const cacheText: string[] = [];