feat(coding-agent): add hidden thinking label api closes #2673

packages/coding-agent/examples/extensions/hidden-thinking-label.ts

@@ -0,0 +1,57 @@
+/**
+ * Hidden Thinking Label Extension
+ *
+ * Demonstrates `ctx.ui.setHiddenThinkingLabel()` for customizing the label shown
+ * when thinking blocks are hidden.
+ *
+ * Usage:
+ *   pi --extension examples/extensions/hidden-thinking-label.ts
+ *
+ * Test:
+ *   1. Load this extension
+ *   2. Hide thinking blocks with Ctrl+T
+ *   3. Ask for something that produces reasoning output
+ *   4. The collapsed thinking block label will show the custom text
+ *
+ * Commands:
+ *   /thinking-label <text>   Set a custom hidden thinking label
+ *   /thinking-label          Reset to the default label
+ */
+
+import type { ExtensionAPI, ExtensionContext } from "@mariozechner/pi-coding-agent";
+
+const DEFAULT_LABEL = "Pondering...";
+
+export default function (pi: ExtensionAPI) {
+	let label = DEFAULT_LABEL;
+
+	const applyLabel = (ctx: ExtensionContext) => {
+		ctx.ui.setHiddenThinkingLabel(label);
+	};
+
+	pi.on("session_start", async (_event, ctx) => {
+		applyLabel(ctx);
+	});
+
+	pi.on("session_switch", async (_event, ctx) => {
+		applyLabel(ctx);
+	});
+
+	pi.registerCommand("thinking-label", {
+		description: "Set the hidden thinking label. Use without args to reset.",
+		handler: async (args, ctx) => {
+			const nextLabel = args.trim();
+
+			if (!nextLabel) {
+				label = DEFAULT_LABEL;
+				ctx.ui.setHiddenThinkingLabel();
+				ctx.ui.notify(`Hidden thinking label reset to: ${DEFAULT_LABEL}`);
+				return;
+			}
+
+			label = nextLabel;
+			ctx.ui.setHiddenThinkingLabel(label);
+			ctx.ui.notify(`Hidden thinking label set to: ${label}`);
+		},
+	});
+}