fix(tui): parse multiline LaTeX arguments

Closes #7760

packages/coding-agent/CHANGELOG.md

@@ -16,6 +16,7 @@
 ### Fixed
 
 - Fixed fullscreen transcript search snapping back to the current match during manual scrolling and fragmented mouse input leaking into the search query.
+- Fixed inherited required LaTeX arguments starting on a new line being parsed as empty ([#7760](https://github.com/earendil-works/pi/issues/7760)).
 
 ## [0.84.1] - 2026-08-07
 

packages/tui/CHANGELOG.md

@@ -14,6 +14,7 @@
 ### Fixed
 
 - Fixed fullscreen transcript search snapping back to the current match during manual scrolling and fragmented SGR mouse input leaking into the search query.
+- Fixed required LaTeX arguments starting on a new line being parsed as empty ([#7760](https://github.com/earendil-works/pi/issues/7760)).
 
 ## [0.84.1] - 2026-08-07
 

packages/tui/src/latex.ts

@@ -1145,7 +1145,7 @@ class LatexParser {
 	}
 
 	private parseRequiredArgumentValue(): string {
-		while (this.position < this.source.length && /[ \t]/.test(this.source[this.position] ?? "")) {
+		while (this.position < this.source.length && /\s/.test(this.source[this.position] ?? "")) {
 			this.position++;
 		}
 		if (this.position >= this.source.length) {

packages/tui/test/latex.test.ts

@@ -443,6 +443,7 @@ R\left(\frac{\pi}{4}\right)
 			"    -b±√(b²-4ac)\nx = ────────────\n         2a",
 		);
 		assert.strictEqual(renderLatex(String.raw`\frac{x^2+1}{x-1}`, { display: true }), "x²+1\n────\nx-1");
+		assert.strictEqual(renderLatex("\\frac{1}\n{2}", { display: true }), "1\n─\n2");
 	});
 
 	it("keeps nested display fractions linear", () => {