diff --git a/packages/coding-agent/examples/extensions/built-in-tool-renderer.ts b/packages/coding-agent/examples/extensions/built-in-tool-renderer.ts
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+++ b/packages/coding-agent/examples/extensions/built-in-tool-renderer.ts
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+/**
+ * Built-in Tool Renderer Example - Custom rendering for built-in tools
+ *
+ * Demonstrates how to override the rendering of built-in tools (read, bash,
+ * edit, write) without changing their behavior. Each tool is re-registered
+ * with the same name, delegating execution to the original implementation
+ * while providing compact custom renderCall/renderResult functions.
+ *
+ * This is useful for users who prefer more concise tool output, or who want
+ * to highlight specific information (e.g., showing only the diff stats for
+ * edit, or just the exit code for bash).
+ *
+ * How it works:
+ * - registerTool() with the same name as a built-in replaces it entirely
+ * - We create instances of the original tools via createReadTool(), etc.
+ *   and delegate execute() to them
+ * - renderCall() controls what's shown when the tool is invoked
+ * - renderResult() controls what's shown after execution completes
+ * - The `expanded` flag in renderResult indicates whether the user has
+ *   toggled the tool output open (via ctrl+e or clicking)
+ *
+ * Usage:
+ *   pi -e ./built-in-tool-renderer.ts
+ */
+
+import type { BashToolDetails, EditToolDetails, ExtensionAPI, ReadToolDetails } from "@mariozechner/pi-coding-agent";
+import { createBashTool, createEditTool, createReadTool, createWriteTool } from "@mariozechner/pi-coding-agent";
+import { Text } from "@mariozechner/pi-tui";
+
+export default function (pi: ExtensionAPI) {
+	const cwd = process.cwd();
+
+	// --- Read tool: show path and line count ---
+	const originalRead = createReadTool(cwd);
+	pi.registerTool({
+		name: "read",
+		label: "read",
+		description: originalRead.description,
+		parameters: originalRead.parameters,
+
+		async execute(toolCallId, params, signal, onUpdate) {
+			return originalRead.execute(toolCallId, params, signal, onUpdate);
+		},
+
+		renderCall(args, theme) {
+			let text = theme.fg("toolTitle", theme.bold("read "));
+			text += theme.fg("accent", args.path);
+			if (args.offset || args.limit) {
+				const parts: string[] = [];
+				if (args.offset) parts.push(`offset=${args.offset}`);
+				if (args.limit) parts.push(`limit=${args.limit}`);
+				text += theme.fg("dim", ` (${parts.join(", ")})`);
+			}
+			return new Text(text, 0, 0);
+		},
+
+		renderResult(result, { expanded, isPartial }, theme) {
+			if (isPartial) return new Text(theme.fg("warning", "Reading..."), 0, 0);
+
+			const details = result.details as ReadToolDetails | undefined;
+			const content = result.content[0];
+
+			if (content?.type === "image") {
+				return new Text(theme.fg("success", "Image loaded"), 0, 0);
+			}
+
+			if (content?.type !== "text") {
+				return new Text(theme.fg("error", "No content"), 0, 0);
+			}
+
+			const lineCount = content.text.split("\n").length;
+			let text = theme.fg("success", `${lineCount} lines`);
+
+			if (details?.truncation?.truncated) {
+				text += theme.fg("warning", ` (truncated from ${details.truncation.totalLines})`);
+			}
+
+			if (expanded) {
+				const lines = content.text.split("\n").slice(0, 15);
+				for (const line of lines) {
+					text += `\n${theme.fg("dim", line)}`;
+				}
+				if (lineCount > 15) {
+					text += `\n${theme.fg("muted", `... ${lineCount - 15} more lines`)}`;
+				}
+			}
+
+			return new Text(text, 0, 0);
+		},
+	});
+
+	// --- Bash tool: show command and exit code ---
+	const originalBash = createBashTool(cwd);
+	pi.registerTool({
+		name: "bash",
+		label: "bash",
+		description: originalBash.description,
+		parameters: originalBash.parameters,
+
+		async execute(toolCallId, params, signal, onUpdate) {
+			return originalBash.execute(toolCallId, params, signal, onUpdate);
+		},
+
+		renderCall(args, theme) {
+			let text = theme.fg("toolTitle", theme.bold("$ "));
+			const cmd = args.command.length > 80 ? `${args.command.slice(0, 77)}...` : args.command;
+			text += theme.fg("accent", cmd);
+			if (args.timeout) {
+				text += theme.fg("dim", ` (timeout: ${args.timeout}s)`);
+			}
+			return new Text(text, 0, 0);
+		},
+
+		renderResult(result, { expanded, isPartial }, theme) {
+			if (isPartial) return new Text(theme.fg("warning", "Running..."), 0, 0);
+
+			const details = result.details as BashToolDetails | undefined;
+			const content = result.content[0];
+			const output = content?.type === "text" ? content.text : "";
+
+			const exitMatch = output.match(/exit code: (\d+)/);
+			const exitCode = exitMatch ? parseInt(exitMatch[1], 10) : null;
+			const lineCount = output.split("\n").filter((l) => l.trim()).length;
+
+			let text = "";
+			if (exitCode === 0 || exitCode === null) {
+				text += theme.fg("success", "done");
+			} else {
+				text += theme.fg("error", `exit ${exitCode}`);
+			}
+			text += theme.fg("dim", ` (${lineCount} lines)`);
+
+			if (details?.truncation?.truncated) {
+				text += theme.fg("warning", " [truncated]");
+			}
+
+			if (expanded) {
+				const lines = output.split("\n").slice(0, 20);
+				for (const line of lines) {
+					text += `\n${theme.fg("dim", line)}`;
+				}
+				if (output.split("\n").length > 20) {
+					text += `\n${theme.fg("muted", "... more output")}`;
+				}
+			}
+
+			return new Text(text, 0, 0);
+		},
+	});
+
+	// --- Edit tool: show path and diff stats ---
+	const originalEdit = createEditTool(cwd);
+	pi.registerTool({
+		name: "edit",
+		label: "edit",
+		description: originalEdit.description,
+		parameters: originalEdit.parameters,
+
+		async execute(toolCallId, params, signal, onUpdate) {
+			return originalEdit.execute(toolCallId, params, signal, onUpdate);
+		},
+
+		renderCall(args, theme) {
+			let text = theme.fg("toolTitle", theme.bold("edit "));
+			text += theme.fg("accent", args.path);
+			return new Text(text, 0, 0);
+		},
+
+		renderResult(result, { expanded, isPartial }, theme) {
+			if (isPartial) return new Text(theme.fg("warning", "Editing..."), 0, 0);
+
+			const details = result.details as EditToolDetails | undefined;
+			const content = result.content[0];
+
+			if (content?.type === "text" && content.text.startsWith("Error")) {
+				return new Text(theme.fg("error", content.text.split("\n")[0]), 0, 0);
+			}
+
+			if (!details?.diff) {
+				return new Text(theme.fg("success", "Applied"), 0, 0);
+			}
+
+			// Count additions and removals from the diff
+			const diffLines = details.diff.split("\n");
+			let additions = 0;
+			let removals = 0;
+			for (const line of diffLines) {
+				if (line.startsWith("+") && !line.startsWith("+++")) additions++;
+				if (line.startsWith("-") && !line.startsWith("---")) removals++;
+			}
+
+			let text = theme.fg("success", `+${additions}`);
+			text += theme.fg("dim", " / ");
+			text += theme.fg("error", `-${removals}`);
+
+			if (expanded) {
+				for (const line of diffLines.slice(0, 30)) {
+					if (line.startsWith("+") && !line.startsWith("+++")) {
+						text += `\n${theme.fg("success", line)}`;
+					} else if (line.startsWith("-") && !line.startsWith("---")) {
+						text += `\n${theme.fg("error", line)}`;
+					} else {
+						text += `\n${theme.fg("dim", line)}`;
+					}
+				}
+				if (diffLines.length > 30) {
+					text += `\n${theme.fg("muted", `... ${diffLines.length - 30} more diff lines`)}`;
+				}
+			}
+
+			return new Text(text, 0, 0);
+		},
+	});
+
+	// --- Write tool: show path and size ---
+	const originalWrite = createWriteTool(cwd);
+	pi.registerTool({
+		name: "write",
+		label: "write",
+		description: originalWrite.description,
+		parameters: originalWrite.parameters,
+
+		async execute(toolCallId, params, signal, onUpdate) {
+			return originalWrite.execute(toolCallId, params, signal, onUpdate);
+		},
+
+		renderCall(args, theme) {
+			let text = theme.fg("toolTitle", theme.bold("write "));
+			text += theme.fg("accent", args.path);
+			const lineCount = args.content.split("\n").length;
+			text += theme.fg("dim", ` (${lineCount} lines)`);
+			return new Text(text, 0, 0);
+		},
+
+		renderResult(result, { isPartial }, theme) {
+			if (isPartial) return new Text(theme.fg("warning", "Writing..."), 0, 0);
+
+			const content = result.content[0];
+			if (content?.type === "text" && content.text.startsWith("Error")) {
+				return new Text(theme.fg("error", content.text.split("\n")[0]), 0, 0);
+			}
+
+			return new Text(theme.fg("success", "Written"), 0, 0);
+		},
+	});
+}