import pi.dev stuff

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diff --git a/pi/agent/extensions/btw/README.md b/pi/agent/extensions/btw/README.md
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+# BTW
+
+Ephemeral side questions for Pi.
+
+This extension adds `/btw`, modeled after Claude Code's side-question flow:
+
+- it uses the current branch conversation as context
+- it asks a separate one-shot question with the current model
+- it does not add the side question or answer to session history
+- it does not expose tools to that side question
+
+## Command
+
+- `/btw <question>`
+  Ask a quick side question without changing the main thread history.
+
+## Usage Flow
+
+### Flow 1: Ask a quick side question
+
+```text
+/btw Why did the current taskwarrior loop happen?
+```
+
+Pi will answer in a temporary overlay. Close it with `Esc`, `Enter`, or `Space`.
+
+### Flow 2: Use it while you are in the middle of another task
+
+```text
+/btw Remind me which file currently owns the SSH host key bootstrap logic.
+```
+
+This is meant for detours and clarifications. The main conversation stays clean.
+
+### Flow 3: Use it in non-interactive mode
+
+```bash
+pi --model openai/gpt-4.1 --no-session -p '/btw Reply with exactly BTW_OK'
+```
+
+In non-interactive mode, the answer is printed directly to stdout.
+
+## Notes And Limits
+
+- `/btw` uses the currently selected model.
+- The side question gets current branch context, not a fresh context.
+- It has no tools. If the answer is not derivable from the supplied context, it should say so.
+- It is best for short clarifications, not long implementation work.
diff --git a/pi/agent/extensions/btw/index.ts b/pi/agent/extensions/btw/index.ts
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+import { complete, type Message, type TextContent, type UserMessage } from "@mariozechner/pi-ai";
+import {
+	BorderedLoader,
+	convertToLlm,
+	type ExtensionAPI,
+	type ExtensionCommandContext,
+	type SessionEntry,
+	type Theme,
+} from "@mariozechner/pi-coding-agent";
+import { matchesKey, truncateToWidth, visibleWidth } from "@mariozechner/pi-tui";
+
+const SYSTEM_PROMPT = `You are answering a side question for the user.
+
+Rules:
+- Use the supplied conversation context if it is relevant.
+- Answer the side question directly and concisely.
+- Do not use tools.
+- Do not invent facts that are not supported by the supplied context.
+- If the answer is not available from the supplied conversation context, say so plainly.
+- Keep the answer short by default unless the user explicitly asks for depth.`;
+
+function extractResponseText(message: Message): string {
+	return message.content
+		.filter((block): block is TextContent => block.type === "text")
+		.map((block) => block.text)
+		.join("\n")
+		.trim();
+}
+
+function getConversationMessages(ctx: ExtensionCommandContext): Message[] {
+	const branch = ctx.sessionManager.getBranch();
+	return branch
+		.filter((entry): entry is SessionEntry & { type: "message" } => entry.type === "message")
+		.map((entry) => entry.message);
+}
+
+function wrapParagraph(text: string, width: number): string[] {
+	if (width <= 1) return [text];
+	if (!text.trim()) return [""];
+
+	const words = text.split(/\s+/).filter(Boolean);
+	if (words.length === 0) return [""];
+
+	const lines: string[] = [];
+	let current = "";
+
+	for (const word of words) {
+		const next = current ? `${current} ${word}` : word;
+		if (visibleWidth(next) <= width) {
+			current = next;
+			continue;
+		}
+
+		if (current) lines.push(current);
+
+		if (visibleWidth(word) <= width) {
+			current = word;
+			continue;
+		}
+
+		let remainder = word;
+		while (visibleWidth(remainder) > width) {
+			lines.push(truncateToWidth(remainder, width, ""));
+			remainder = remainder.slice(lines[lines.length - 1]!.length);
+		}
+		current = remainder;
+	}
+
+	if (current) lines.push(current);
+	return lines.length > 0 ? lines : [""];
+}
+
+function wrapText(text: string, width: number): string[] {
+	return text.split(/\r?\n/).flatMap((line) => wrapParagraph(line, width));
+}
+
+class BtwOverlay {
+	constructor(
+		private readonly theme: Theme,
+		private readonly question: string,
+		private readonly answer: string,
+		private readonly done: () => void,
+	) {}
+
+	handleInput(data: string): void {
+		if (matchesKey(data, "escape") || matchesKey(data, "return") || data === " " || data === "\r") {
+			this.done();
+		}
+	}
+
+	render(width: number): string[] {
+		const innerWidth = Math.max(20, width - 2);
+		const contentWidth = Math.max(10, innerWidth - 2);
+		const lines: string[] = [];
+
+		const pad = (text: string) => {
+			const visible = visibleWidth(text);
+			return text + " ".repeat(Math.max(0, innerWidth - visible));
+		};
+
+		const row = (text = "") => `${this.theme.fg("border", "│")}${pad(text)}${this.theme.fg("border", "│")}`;
+		const addWrappedSection = (label: string, value: string) => {
+			lines.push(row(` ${this.theme.fg("accent", label)}`));
+			for (const wrapped of wrapText(value || "(no answer)", contentWidth)) {
+				lines.push(row(` ${wrapped}`));
+			}
+			lines.push(row());
+		};
+
+		lines.push(this.theme.fg("border", `╭${"─".repeat(innerWidth)}╮`));
+		lines.push(row(` ${this.theme.fg("accent", "BTW")}${this.theme.fg("muted", "  Side question")}`));
+		lines.push(row());
+		addWrappedSection("Question", this.question);
+		addWrappedSection("Answer", this.answer || "(no answer)");
+		lines.push(row(this.theme.fg("dim", " Esc, Enter, or Space to close")));
+		lines.push(this.theme.fg("border", `╰${"─".repeat(innerWidth)}╯`));
+
+		return lines;
+	}
+
+	invalidate(): void {}
+}
+
+async function runBtw(question: string, ctx: ExtensionCommandContext): Promise<string> {
+	if (!ctx.model) {
+		throw new Error("No model selected.");
+	}
+
+	const branchMessages = getConversationMessages(ctx);
+	const llmMessages = convertToLlm(branchMessages);
+	const apiKey = await ctx.modelRegistry.getApiKey(ctx.model);
+	const userMessage: UserMessage = {
+		role: "user",
+		content: [{ type: "text", text: question }],
+		timestamp: Date.now(),
+	};
+
+	const response = await complete(
+		ctx.model,
+		{
+			systemPrompt: SYSTEM_PROMPT,
+			messages: [...llmMessages, userMessage],
+		},
+		{ apiKey },
+	);
+
+	if (response.stopReason === "aborted") {
+		throw new Error("Cancelled.");
+	}
+
+	return extractResponseText(response) || "(no answer)";
+}
+
+export default function btwExtension(pi: ExtensionAPI): void {
+	pi.registerCommand("btw", {
+		description: "Ask a quick side question without adding it to the conversation",
+		handler: async (args, ctx) => {
+			const question = args.trim();
+			if (!question) {
+				const usage = "Usage: /btw <side question>";
+				if (!ctx.hasUI) process.stdout.write(`${usage}\n`);
+				else ctx.ui.notify(usage, "warning");
+				return;
+			}
+
+			if (!ctx.model) {
+				const error = "No model selected.";
+				if (!ctx.hasUI) process.stdout.write(`${error}\n`);
+				else ctx.ui.notify(error, "error");
+				return;
+			}
+
+			if (!ctx.hasUI) {
+				try {
+					const answer = await runBtw(question, ctx);
+					process.stdout.write(`${answer}\n`);
+				} catch (error) {
+					const text = error instanceof Error ? error.message : String(error);
+					process.stdout.write(`${text}\n`);
+				}
+				return;
+			}
+
+			const answer = await ctx.ui.custom<string | null>(
+				(tui, theme, _kb, done) => {
+					const loader = new BorderedLoader(tui, theme, `Asking BTW using ${ctx.model!.id}...`);
+					loader.onAbort = () => done(null);
+
+					runBtw(question, ctx)
+						.then(done)
+						.catch((error) => {
+							const text = error instanceof Error ? error.message : String(error);
+							done(`BTW failed: ${text}`);
+						});
+
+					return loader;
+				},
+				{
+					overlay: true,
+					overlayOptions: {
+						width: "50%",
+						minWidth: 50,
+						maxHeight: "80%",
+						anchor: "right-center",
+						offsetX: -1,
+					},
+				},
+			);
+
+			if (answer === null) {
+				ctx.ui.notify("BTW cancelled.", "info");
+				return;
+			}
+
+			await ctx.ui.custom<void>(
+				(_tui, theme, _kb, done) => new BtwOverlay(theme, question, answer, done),
+				{
+					overlay: true,
+					overlayOptions: {
+						width: "55%",
+						minWidth: 56,
+						maxHeight: "85%",
+						anchor: "right-center",
+						offsetX: -1,
+					},
+				},
+			);
+		},
+	});
+}