diff --git a/packages/coding-agent/test/transcript-streaming-commit-repro.test.ts b/packages/coding-agent/test/transcript-streaming-commit-repro.test.ts
index 404f1598c..c92ca031b 100644
--- a/packages/coding-agent/test/transcript-streaming-commit-repro.test.ts
+++ b/packages/coding-agent/test/transcript-streaming-commit-repro.test.ts
@@ -148,4 +148,46 @@ describe("transcript streaming commit (assistant text)", () => {
 			await term.flush();
 		}
 	});
+
+	it("keeps the final closed diff row highlighted while following prose streams", async () => {
+		if (process.platform === "win32") return;
+		const rows = 6;
+		const term = new VirtualTerminal(52, rows);
+		Object.defineProperty(term, "isNativeViewportAtBottom", { configurable: true, value: () => undefined });
+		const scheduler = new StressRenderScheduler();
+		const tui = new TUI(term, undefined, { renderScheduler: scheduler });
+		const chat = new TranscriptContainer();
+		const block = new StreamingMarkdownBlock();
+		const diffLines = Array.from({ length: 18 }, (_value, index) => {
+			const sign = index % 2 === 0 ? "-" : "+";
+			return `${sign}closed-${String(index).padStart(2, "0")}`;
+		});
+		const finalDiffLine = "+closed-tail-no-extra-newline";
+		const codeBlockSource = [...diffLines, finalDiffLine].join("\n");
+		const streamingProse = Array.from(
+			{ length: 12 },
+			(_value, index) => `still streaming prose line ${String(index).padStart(2, "0")}`,
+		).join("\n");
+		const closedFenceWithLiveTail = `\`\`\`diff\n${codeBlockSource}\n\`\`\`\n${streamingProse}`;
+		chat.addChild(block);
+		tui.addChild(chat);
+
+		try {
+			tui.start();
+			await scheduler.drain(term);
+
+			block.setStreamingText(closedFenceWithLiveTail);
+			tui.requestRender();
+			await scheduler.drain(term);
+
+			const streamedRows = term.getScrollBuffer().map(row => Bun.stripANSI(row).trimEnd());
+			const finalDiffRow = streamedRows.findIndex(row => row.includes(finalDiffLine));
+			expect(finalDiffRow).toBeGreaterThanOrEqual(0);
+			expect(finalDiffRow).toBeLessThan(term.getBufferPosition().baseY);
+			expect(foregroundColumnsForBufferRow(term, finalDiffRow).length).toBeGreaterThan(0);
+		} finally {
+			tui.stop();
+			await term.flush();
+		}
+	});
 });
diff --git a/packages/tui/src/components/markdown.ts b/packages/tui/src/components/markdown.ts
index dd3f642ed..6f1ebd40d 100644
--- a/packages/tui/src/components/markdown.ts
+++ b/packages/tui/src/components/markdown.ts
@@ -1421,16 +1421,19 @@ export class Markdown implements Component {
 		}
 
 		if (canStreamDiff) {
+			const closedFence = this.#codeTokenHasClosingFence(token);
 			const lineEnd = tokenText.lastIndexOf("\n");
-			if (lineEnd >= 0) {
-				const completedText = tokenText.slice(0, lineEnd);
-				if (completedText.length > 0) {
+			if (closedFence || lineEnd >= 0) {
+				const completedText = closedFence ? tokenText : tokenText.slice(0, lineEnd);
+				if (closedFence || completedText.length > 0) {
 					for (const hlLine of this.#highlightStreamingDiffLines(completedText, lang)) {
 						bodyLines.push(`${codeIndent}${hlLine}`);
 					}
 				}
-				for (const codeLine of tokenText.slice(lineEnd + 1).split("\n")) {
-					bodyLines.push(`${codeIndent}${this.#theme.codeBlock(codeLine)}`);
+				if (!closedFence) {
+					for (const codeLine of tokenText.slice(lineEnd + 1).split("\n")) {
+						bodyLines.push(`${codeIndent}${this.#theme.codeBlock(codeLine)}`);
+					}
 				}
 				return bodyLines;
 			}
@@ -1442,6 +1445,37 @@ export class Markdown implements Component {
 		return bodyLines;
 	}
 
+	#codeTokenHasClosingFence(token: Token): boolean {
+		const raw = "raw" in token && typeof token.raw === "string" ? token.raw : "";
+		const firstLineEnd = raw.indexOf("\n");
+		if (firstLineEnd < 0) return false;
+		const openingLine = raw.slice(0, firstLineEnd);
+		const openingTrimmed = openingLine.trimStart();
+		const openingIndent = openingLine.length - openingTrimmed.length;
+		if (openingIndent > 3) return false;
+		const fenceChar = openingTrimmed.charAt(0);
+		if (fenceChar !== "`" && fenceChar !== "~") return false;
+		let fenceLength = 0;
+		while (openingTrimmed.charAt(fenceLength) === fenceChar) fenceLength++;
+		if (fenceLength < 3) return false;
+
+		let lineStart = firstLineEnd + 1;
+		while (lineStart <= raw.length) {
+			const lineEnd = raw.indexOf("\n", lineStart);
+			const line = lineEnd >= 0 ? raw.slice(lineStart, lineEnd) : raw.slice(lineStart);
+			const trimmed = line.trimStart();
+			const indent = line.length - trimmed.length;
+			let closingLength = 0;
+			while (trimmed.charAt(closingLength) === fenceChar) closingLength++;
+			if (indent <= 3 && closingLength >= fenceLength && trimmed.slice(closingLength).trim().length === 0) {
+				return true;
+			}
+			if (lineEnd < 0) break;
+			lineStart = lineEnd + 1;
+		}
+		return false;
+	}
+
 	#highlightStreamingDiffLines(completedText: string, lang: string | undefined): readonly string[] {
 		const highlightCode = this.#theme.highlightCode;
 		if (!highlightCode) return [];