From 25026d72e36e3e58deb87c9ee1a78f24d0a99e40 Mon Sep 17 00:00:00 2001
From: shanevcantwell <153727980+shanevcantwell@users.noreply.github.com>
Date: Thu, 12 Feb 2026 22:23:18 -0700
Subject: [PATCH] fix: strengthen default Apply prompt for local models

Local models respond to the existing single-sentence Apply prompt with
prose summaries instead of code. Return ChatMessage[] with explicit
code-only instructions and assistant prefill to force code output.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 core/llm/templates/edit/gpt.ts | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/core/llm/templates/edit/gpt.ts b/core/llm/templates/edit/gpt.ts
index 232c9de5e34..9f2ed7c6a71 100644
--- a/core/llm/templates/edit/gpt.ts
+++ b/core/llm/templates/edit/gpt.ts
@@ -73,8 +73,31 @@ export const gptEditPrompt: PromptTemplateFunction = (history, otherData) => {
 };
 
 export const defaultApplyPrompt: PromptTemplateFunction = (
-  history,
+  _history,
   otherData,
 ) => {
-  return `${otherData.original_code}\n\nThe following code was suggested as an edit:\n\`\`\`\n${otherData.new_code}\n\`\`\`\nPlease apply it to the previous code. Leave existing comments in place unless changes require modifying them.`;
+  return [
+    {
+      role: "user",
+      content: dedent`
+        ORIGINAL CODE:
+        \`\`\`
+        ${otherData.original_code}
+        \`\`\`
+
+        SUGGESTED EDIT:
+        \`\`\`
+        ${otherData.new_code}
+        \`\`\`
+
+        Apply the SUGGESTED EDIT to the ORIGINAL CODE. Output the complete modified file.
+        - Output ONLY code. Do NOT explain, summarize, or describe changes.
+        - Leave existing comments in place unless changes require modifying them.
+        - Preserve all unchanged code exactly as-is.`,
+    },
+    {
+      role: "assistant",
+      content: `\`\`\`\n`,
+    },
+  ];
 };