feat(status-bar): add real-time streaming speed indicator (#30)

* feat(status-bar): add real-time streaming speed indicator

* docs: update changelog

Author: kostyay

CHANGELOG.md

@@ -56,7 +56,13 @@ All notable changes to agent-stuff are documented here.
 
 
 
-## feat/auto-simplify-session-isolation
+
+
+## feat/streaming-speed-display
+
+Added a real-time streaming speed indicator to the status bar that displays throughput in bytes/second during Claude's message generation (#30). The indicator uses a 1-second sliding window to track bytes from text, thinking, and tool-call deltas, with automatic unit scaling (B/s, kB/s, MB/s) for readability. Speed updates are rendered via a dedicated interval timer that triggers UI refreshes only during active streaming, replacing the previous token count display when streams are active. The feature properly manages lifecycle hooks—clearing timers on message completion and footer disposal to prevent memory leaks.
+
+## [1.0.18](https://github.com/kostyay/agent-stuff/pull/29) - 2026-03-07
 
 Implements session isolation for auto-triggered simplifications (#29), ensuring that files queued from the `agent_end` confirmation create a new isolated session before execution rather than running in the current context. This prevents simplification work from interfering with ongoing analysis and improves context management. The implementation queues files internally and defers their processing to the next `/simplify` invocation, which detects pending auto-simplify work and establishes a fresh session with appropriate naming before proceeding.
 

pi-extensions/status-bar.ts

@@ -17,6 +17,7 @@
 import type { AssistantMessage } from "@mariozechner/pi-ai";
 import type { ExtensionAPI, ExtensionContext } from "@mariozechner/pi-coding-agent";
 import { truncateToWidth, visibleWidth } from "@mariozechner/pi-tui";
+import { Buffer } from "node:buffer";
 import { basename } from "node:path";
 
 /** Hash a string into a 32-bit unsigned integer (djb2). */
@@ -84,6 +85,13 @@ export function buildProfileBadge(ctx: ExtensionContext): { text: string; width:
 	};
 }
 
+/** Format bytes/sec as a compact string (e.g. 512B/s, 1.2kB/s). */
+export function formatBytesPerSec(bps: number): string {
+	if (bps >= 1_000_000) return `${(bps / 1_000_000).toFixed(1)}MB/s`;
+	if (bps >= 1_000) return `${(bps / 1_000).toFixed(1)}kB/s`;
+	return `${Math.round(bps)}B/s`;
+}
+
 /** Format a token count as a compact string (e.g. 1.2k, 3.5M). */
 export function formatTokenCount(n: number): string {
 	if (n >= 1_000_000) return `${(n / 1_000_000).toFixed(1).replace(/\.0$/, "")}M`;
@@ -124,6 +132,13 @@ export default function statusBarExtension(pi: ExtensionAPI) {
 	let turnCount = 0;
 	let agentActive = false;
 
+	// Real-time streaming speed (bytes/sec, 1s sliding window)
+	let windowBytes = 0;
+	let currentBytesPerSec = 0;
+	let isStreaming = false;
+	let renderTimer: ReturnType<typeof setInterval> | null = null;
+	let tuiRef: { requestRender: () => void } | null = null;
+
 	// Ticket stats (populated via pi.events from ticket extension)
 	let ticketStats: TicketStats | null = null;
 	pi.events.on("ticket:stats", (data: unknown) => { ticketStats = data as TicketStats; });
@@ -188,6 +203,36 @@ export default function statusBarExtension(pi: ExtensionAPI) {
 		diffStatsTimer = setTimeout(() => refreshDiffStats(ctx), 500);
 	}
 
+	pi.on("message_start", async (event) => {
+		if (event.message.role !== "assistant") return;
+		windowBytes = 0;
+		currentBytesPerSec = 0;
+		isStreaming = true;
+		if (tuiRef && !renderTimer) {
+			renderTimer = setInterval(() => {
+				currentBytesPerSec = windowBytes;
+				windowBytes = 0;
+				tuiRef?.requestRender();
+			}, 1000);
+		}
+	});
+
+	pi.on("message_update", async (event) => {
+		const e = event.assistantMessageEvent;
+		if (e.type === "text_delta" || e.type === "thinking_delta" || e.type === "toolcall_delta") {
+			windowBytes += Buffer.byteLength(e.delta, "utf8");
+		}
+	});
+
+	pi.on("message_end", async (event) => {
+		if (event.message.role !== "assistant") return;
+		isStreaming = false;
+		if (renderTimer) {
+			clearInterval(renderTimer);
+			renderTimer = null;
+		}
+	});
+
 	pi.on("tool_execution_end", async (event, ctx) => {
 		counts[event.toolName] = (counts[event.toolName] || 0) + 1;
 		if (MUTATING_TOOLS.has(event.toolName)) scheduleDiffRefresh(ctx);
@@ -217,10 +262,15 @@ export default function statusBarExtension(pi: ExtensionAPI) {
 		refreshDiffStats(ctx);
 
 		ctx.ui.setFooter((tui, theme, footerData) => {
+			tuiRef = tui;
 			const unsub = footerData.onBranchChange(() => tui.requestRender());
 
 			return {
-				dispose: unsub,
+				dispose() {
+					unsub();
+					if (renderTimer) { clearInterval(renderTimer); renderTimer = null; }
+					tuiRef = null;
+				},
 				invalidate() {},
 				render(width: number): string[] {
 					let tokIn = 0;
@@ -261,10 +311,14 @@ export default function statusBarExtension(pi: ExtensionAPI) {
 						theme.fg("dim", " ") +
 						theme.fg(ctxColor, `${Math.round(pct)}%`);
 
-					let l1Right =
-						theme.fg("success", `↑${formatTokenCount(tokIn)}`) +
-						theme.fg("dim", " ") +
-						theme.fg("accent", `↓${formatTokenCount(tokOut)}`);
+					const speedLabel = isStreaming && currentBytesPerSec === 0
+						? "…"
+						: currentBytesPerSec > 0 || isStreaming
+							? formatBytesPerSec(currentBytesPerSec)
+							: "";
+					let l1Right = speedLabel
+						? theme.fg("muted", `⏱${speedLabel}`)
+						: "";
 					if (tokCache > 0) {
 						l1Right += theme.fg("dim", " ") + theme.fg("muted", `⚡${formatTokenCount(tokCache)}`);
 					}
@@ -395,6 +449,10 @@ export default function statusBarExtension(pi: ExtensionAPI) {
 			turnCount = 0;
 			agentActive = false;
 			diffStats = null;
+			windowBytes = 0;
+			currentBytesPerSec = 0;
+			isStreaming = false;
+			if (renderTimer) { clearInterval(renderTimer); renderTimer = null; }
 			refreshDiffStats(ctx);
 		}
 	});