fix(coding-agent): show errors from write tool in UI

fixes #856

packages/coding-agent/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Fixed `write` tool not displaying errors in the UI when execution fails ([#856](https://github.com/badlogic/pi-mono/issues/856))
+
 ## [0.49.2] - 2026-01-19
 
 ### Added

packages/coding-agent/src/modes/interactive/components/tool-execution.ts

@@ -542,6 +542,14 @@ export class ToolExecutionComponent extends Container {
 						` ${keyHint("expandTools", "to expand")})`;
 				}
 			}
+
+			// Show error if tool execution failed
+			if (this.result?.isError) {
+				const errorText = this.getTextOutput();
+				if (errorText) {
+					text += `\n\n${theme.fg("error", errorText)}`;
+				}
+			}
 		} else if (this.toolName === "edit") {
 			const rawPath = this.args?.file_path || this.args?.path || "";
 			const path = shortenPath(rawPath);