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 c92ca031b..2fd6f8b46 100644
--- a/packages/coding-agent/test/transcript-streaming-commit-repro.test.ts
+++ b/packages/coding-agent/test/transcript-streaming-commit-repro.test.ts
@@ -190,4 +190,33 @@ describe("transcript streaming commit (assistant text)", () => {
 			await term.flush();
 		}
 	});
+
+	it("renders a leading completed blank row in an open streamed diff body", () => {
+		const block = new StreamingMarkdownBlock();
+		block.setStreamingText("```diff\n\n+next");
+
+		const rows = block.render(40).map(row => Bun.stripANSI(row).trimEnd());
+		const fenceRow = rows.indexOf("```diff");
+
+		expect(fenceRow).toBeGreaterThanOrEqual(0);
+		expect(rows.slice(fenceRow, fenceRow + 4)).toEqual(["```diff", "", "  +next", "```"]);
+	});
+
+	it("appends a completed blank row when the streamed diff line cache grows", () => {
+		const block = new StreamingMarkdownBlock();
+
+		block.setStreamingText("```diff\n+a\n+streaming");
+		const initialRows = block.render(40).map(row => Bun.stripANSI(row).trimEnd());
+		const initialCodeRow = initialRows.indexOf("  +a");
+		expect(initialCodeRow).toBeGreaterThanOrEqual(0);
+		expect(initialRows.slice(initialCodeRow, initialCodeRow + 2)).toEqual(["  +a", "  +streaming"]);
+
+		block.setStreamingText("```diff\n+a\n\n+streaming");
+
+		const rows = block.render(40).map(row => Bun.stripANSI(row).trimEnd());
+		const codeRow = rows.indexOf("  +a");
+
+		expect(codeRow).toBeGreaterThanOrEqual(0);
+		expect(rows.slice(codeRow, codeRow + 3)).toEqual(["  +a", "", "  +streaming"]);
+	});
 });
diff --git a/packages/tui/src/components/markdown.ts b/packages/tui/src/components/markdown.ts
index 6f1ebd40d..9d87eac21 100644
--- a/packages/tui/src/components/markdown.ts
+++ b/packages/tui/src/components/markdown.ts
@@ -1425,10 +1425,8 @@ export class Markdown implements Component {
 			const lineEnd = tokenText.lastIndexOf("\n");
 			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 hlLine of this.#highlightStreamingDiffLines(completedText, lang)) {
+					bodyLines.push(`${codeIndent}${hlLine}`);
 				}
 				if (!closedFence) {
 					for (const codeLine of tokenText.slice(lineEnd + 1).split("\n")) {
@@ -1502,10 +1500,8 @@ export class Markdown implements Component {
 			if (completedText.length === cache.text.length) return cache.lines;
 			const lines = cache.lines.slice();
 			const addedText = completedText.slice(cache.text.length === 0 ? 0 : cache.text.length + 1);
-			if (addedText.length > 0) {
-				for (const codeLine of addedText.split("\n")) {
-					lines.push(...highlightCode(codeLine, lang));
-				}
+			for (const codeLine of addedText.split("\n")) {
+				lines.push(...highlightCode(codeLine, lang));
 			}
 			this.#streamingDiffLineCache = { ...signature, lang, text: completedText, lines };
 			return lines;