diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 46805a0e..e4682cce 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -7,6 +7,10 @@
 - API keys in `auth.json` now support shell command resolution (`!command`) and environment variable lookup, matching the behavior in `models.json`
 - Added `minimal-mode.ts` example extension demonstrating how to override built-in tool rendering for a minimal display mode
 
+### Fixed
+
+- Fixed HTML export losing indentation in ANSI-rendered tool output (e.g. JSON code blocks in custom tool results)
+
 ## [0.51.6] - 2026-02-04
 
 ### New Features
diff --git a/packages/coding-agent/src/core/export-html/template.css b/packages/coding-agent/src/core/export-html/template.css
index d64cc068..bbf8e326 100644
--- a/packages/coding-agent/src/core/export-html/template.css
+++ b/packages/coding-agent/src/core/export-html/template.css
@@ -503,6 +503,10 @@
       display: block;
     }
 
+    .ansi-line {
+      white-space: pre-wrap;
+    }
+
     .tool-images {
     }