diff --git a/changelog.md b/changelog.md
index b6caa5050..910db1227 100644
--- a/changelog.md
+++ b/changelog.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 <!-- Add all new changes here. They will be moved under a version at release -->
+* `FIX` Fix diagnostic completions incorrect textEdit.finish
 
 ## 3.16.0
 `2025-12-2`
diff --git a/script/core/completion/completion.lua b/script/core/completion/completion.lua
index f751e53d5..97cb093ae 100644
--- a/script/core/completion/completion.lua
+++ b/script/core/completion/completion.lua
@@ -1925,7 +1925,7 @@ local function tryluaDocBySource(state, position, source, results)
                     kind     = define.CompletionItemKind.Enum,
                     textEdit = {
                         start   = source.start,
-                        finish  = source.start + #source.mode - 1,
+                        finish  = source.start + #source.mode,
                         newText = mode,
                     },
                 }
@@ -1940,7 +1940,7 @@ local function tryluaDocBySource(state, position, source, results)
                     kind     = define.CompletionItemKind.Value,
                     textEdit = {
                         start   = source.start,
-                        finish  = source.start + #source[1] - 1,
+                        finish  = source.start + #source[1],
                         newText = name,
                     },
                 }