From aa17a8a4191a04604b3a402e75d5c7e7b8149da4 Mon Sep 17 00:00:00 2001
From: marius-kilocode <marius@kilocode.ai>
Date: Thu, 18 Jun 2026 15:01:12 +0200
Subject: [PATCH] fix(vscode): keep diff identifiers intact

---
 .changeset/keep-diff-identifiers-intact.md | 5 +++++
 packages/kilo-ui/src/pierre/index.test.ts  | 6 +++---
 packages/kilo-ui/src/pierre/index.ts       | 4 +++-
 3 files changed, 11 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/keep-diff-identifiers-intact.md

diff --git a/.changeset/keep-diff-identifiers-intact.md b/.changeset/keep-diff-identifiers-intact.md
new file mode 100644
index 0000000000..57c03dbff5
--- /dev/null
+++ b/.changeset/keep-diff-identifiers-intact.md
@@ -0,0 +1,5 @@
+---
+"kilo-code": patch
+---
+
+Keep changed identifiers intact when highlighting edits within diff lines.
diff --git a/packages/kilo-ui/src/pierre/index.test.ts b/packages/kilo-ui/src/pierre/index.test.ts
index 5f2df0e951..7bc73fd3a2 100644
--- a/packages/kilo-ui/src/pierre/index.test.ts
+++ b/packages/kilo-ui/src/pierre/index.test.ts
@@ -2,8 +2,8 @@ import { describe, expect, test } from "bun:test"
 import { createDefaultOptions } from "./index"
 
 describe("Pierre diff options", () => {
-  test("highlights changed characters in unified and split diffs", () => {
-    expect(createDefaultOptions("unified").lineDiffType).toBe("char")
-    expect(createDefaultOptions("split").lineDiffType).toBe("char")
+  test("keeps changed identifiers intact in unified and split diffs", () => {
+    expect(createDefaultOptions("unified").lineDiffType).toBe("word-alt")
+    expect(createDefaultOptions("split").lineDiffType).toBe("word-alt")
   })
 })
diff --git a/packages/kilo-ui/src/pierre/index.ts b/packages/kilo-ui/src/pierre/index.ts
index 1df03fb88d..7b4b13aabe 100644
--- a/packages/kilo-ui/src/pierre/index.ts
+++ b/packages/kilo-ui/src/pierre/index.ts
@@ -10,7 +10,9 @@ import { createDefaultOptions as defaults, styleVariables } from "@opencode-ai/u
 
 export { styleVariables }
 
-export const LINE_DIFF_TYPE = "char" as const
+// Character matching fragments inserted identifiers when they share letters with
+// existing symbols. Word-alt keeps those logical additions visually intact.
+export const LINE_DIFF_TYPE = "word-alt" as const
 
 // Pierre 1.1 treats its changed-line override properties as tint targets. Apply
 // Kilo semantic surfaces at the computed row level so host diff colors stay final.