From db3d41622c8e9b1885490deb0dc7321cab6a8fdc Mon Sep 17 00:00:00 2001
From: can1357 <me@can.ac>
Date: Sat, 31 Jan 2026 13:15:39 +0100
Subject: [PATCH] perf(coding-agent/tools): implemented caching in table and
 cell renderers to avoid redundant recalculations

- Implemented caching in table and cell results renderers to avoid redundant recalculations when width or cell data hasn't changed.
- Added cache invalidation logic to clear cached render results when cell data or spinner state changes.
---
 packages/coding-agent/CHANGELOG.md        |  2 +-
 packages/coding-agent/src/tools/python.ts | 29 +++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 278d47b5b..4e3b5b0c6 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -1,9 +1,9 @@
 # Changelog
 
 ## [Unreleased]
-
 ### Changed
 
+- Improved rendering performance for Python cell output by implementing caching in the table and cell results renderers
 - Updated task tool documentation to clarify that subagents can access parent conversation context via a searchable file, reducing need to repeat information in context parameter
 - Updated plan mode prompt to guide model toward using `edit` tool for incremental plan updates instead of defaulting to `write`
 
diff --git a/packages/coding-agent/src/tools/python.ts b/packages/coding-agent/src/tools/python.ts
index 18910f23a..8c59ebd0f 100644
--- a/packages/coding-agent/src/tools/python.ts
+++ b/packages/coding-agent/src/tools/python.ts
@@ -785,8 +785,15 @@ export const pythonToolRenderer = {
 			return new Text(text, 0, 0);
 		}
 
+		// Cache state - cells don't change, only width varies
+		let cached: { width: number; result: string[] } | undefined;
+
 		return {
 			render: (width: number): string[] => {
+				if (cached && cached.width === width) {
+					return cached.result;
+				}
+
 				const lines: string[] = [];
 				for (let i = 0; i < cells.length; i++) {
 					const cell = cells[i];
@@ -812,9 +819,12 @@ export const pythonToolRenderer = {
 						lines.push("");
 					}
 				}
+				cached = { width, result: lines };
 				return lines;
 			},
-			invalidate: () => {},
+			invalidate: () => {
+				cached = undefined;
+			},
 		};
 	},
 
@@ -864,8 +874,20 @@ export const pythonToolRenderer = {
 
 		const cellResults = details?.cells;
 		if (cellResults && cellResults.length > 0) {
+			// Cache state following Box pattern
+			let cached: { key: string; width: number; result: string[] } | undefined;
+
+			const buildCacheKey = (spinnerFrame: number | undefined): string => {
+				return `${expanded}|${previewLines}|${spinnerFrame}`;
+			};
+
 			return {
 				render: (width: number): string[] => {
+					const key = buildCacheKey(options.spinnerFrame);
+					if (cached && cached.key === key && cached.width === width) {
+						return cached.result;
+					}
+
 					const lines: string[] = [];
 					for (let i = 0; i < cellResults.length; i++) {
 						const cell = cellResults[i];
@@ -921,9 +943,12 @@ export const pythonToolRenderer = {
 					if (warningLine) {
 						lines.push(warningLine);
 					}
+					cached = { key, width, result: lines };
 					return lines;
 				},
-				invalidate: () => {},
+				invalidate: () => {
+					cached = undefined;
+				},
 			};
 		}