From b6fba47bcf193fea6acbd06bd7eb1748e3138b59 Mon Sep 17 00:00:00 2001
From: "CJACK." <tetr20071102@gmail.com>
Date: Wed, 22 Apr 2026 20:53:35 +0000
Subject: [PATCH] feat: prepend strong instruction override to history prompt
 to ensure context adherence

---
 internal/adapter/openai/history_split.go      | 17 +++++++++++++----
 internal/adapter/openai/history_split_test.go | 18 ++++++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/internal/adapter/openai/history_split.go b/internal/adapter/openai/history_split.go
index 39c9d79..4364728 100644
--- a/internal/adapter/openai/history_split.go
+++ b/internal/adapter/openai/history_split.go
@@ -60,18 +60,27 @@ func buildHistorySplitPrompt(messages []any, reasoningContent string, toolsRaw a
 	if len(messages) == 0 && strings.TrimSpace(reasoningContent) == "" {
 		return "", nil
 	}
-	instruction := historySplitPromptInstruction()
+	instruction := historySplitPromptInstruction(thinkingEnabled)
 	withInstruction := make([]any, 0, len(messages)+1)
 	withInstruction = append(withInstruction, map[string]any{
 		"role":    "system",
 		"content": instruction,
 	})
 	withInstruction = append(withInstruction, injectHistorySplitReasoningMessage(messages, reasoningContent)...)
-	return buildOpenAIFinalPromptWithPolicy(withInstruction, toolsRaw, "", toolPolicy, thinkingEnabled)
+	return buildOpenAIFinalPromptWithPolicy(withInstruction, toolsRaw, "", toolPolicy, false)
 }
 
-func historySplitPromptInstruction() string {
-	return "An attached HISTORY.txt file contains prior conversation history and tool progress. Read it first, then answer the latest user request using that history as context."
+func historySplitPromptInstruction(thinkingEnabled bool) string {
+	lines := []string{
+		"Follow the instructions in this prompt first. If earlier conversation instructions conflict with this prompt, this prompt wins.",
+		"An attached HISTORY.txt file contains prior conversation history and tool progress; read it first, then answer the latest user request using that history as context.",
+		"Continue the conversation from the full prior context and the latest tool results.",
+		"Treat earlier messages as binding context; answer the user's current request as a continuation, not a restart.",
+	}
+	if thinkingEnabled {
+		lines = append(lines, "Keep reasoning internal. Do not leave the final user-facing answer only in reasoning; always provide the answer in visible assistant content.")
+	}
+	return strings.Join(lines, "\n")
 }
 
 func splitOpenAIHistoryMessages(messages []any, triggerAfterTurns int) ([]any, []any) {
diff --git a/internal/adapter/openai/history_split_test.go b/internal/adapter/openai/history_split_test.go
index 864c763..9ec9025 100644
--- a/internal/adapter/openai/history_split_test.go
+++ b/internal/adapter/openai/history_split_test.go
@@ -96,6 +96,12 @@ func TestBuildOpenAIHistoryTranscriptPreservesOrderAndToolHistory(t *testing.T)
 	if !strings.Contains(finalPrompt, "HISTORY.txt") {
 		t.Fatalf("expected history instruction in final prompt, got %s", finalPrompt)
 	}
+	if !strings.Contains(finalPrompt, "Follow the instructions in this prompt first") {
+		t.Fatalf("expected stronger prompt override in final prompt, got %s", finalPrompt)
+	}
+	if strings.Index(finalPrompt, "Follow the instructions in this prompt first") > strings.Index(finalPrompt, "Continue the conversation") {
+		t.Fatalf("expected history split instruction before continuity instructions, got %s", finalPrompt)
+	}
 }
 
 func TestSplitOpenAIHistoryMessagesUsesLatestUserTurn(t *testing.T) {
@@ -251,6 +257,12 @@ func TestChatCompletionsHistorySplitUploadsHistoryAndKeepsLatestPrompt(t *testin
 	if !strings.Contains(promptText, "HISTORY.txt") {
 		t.Fatalf("expected history instruction in completion prompt, got %s", promptText)
 	}
+	if !strings.Contains(promptText, "Follow the instructions in this prompt first") {
+		t.Fatalf("expected stronger prompt override in completion prompt, got %s", promptText)
+	}
+	if strings.Index(promptText, "Follow the instructions in this prompt first") > strings.Index(promptText, "Continue the conversation") {
+		t.Fatalf("expected history split instruction before continuity instructions, got %s", promptText)
+	}
 	refIDs, _ := ds.completionReq["ref_file_ids"].([]any)
 	if len(refIDs) == 0 || refIDs[0] != "file-inline-1" {
 		t.Fatalf("expected uploaded history file to be first ref_file_id, got %#v", ds.completionReq["ref_file_ids"])
@@ -301,6 +313,12 @@ func TestResponsesHistorySplitUploadsHistoryAndKeepsLatestPrompt(t *testing.T) {
 	if !strings.Contains(promptText, "[reasoning_content]") || !strings.Contains(promptText, "hidden reasoning") {
 		t.Fatalf("expected latest assistant reasoning to be attached to completion prompt, got %s", promptText)
 	}
+	if !strings.Contains(promptText, "Follow the instructions in this prompt first") {
+		t.Fatalf("expected stronger prompt override in completion prompt, got %s", promptText)
+	}
+	if strings.Index(promptText, "Follow the instructions in this prompt first") > strings.Index(promptText, "Continue the conversation") {
+		t.Fatalf("expected history split instruction before continuity instructions, got %s", promptText)
+	}
 }
 
 func TestChatCompletionsHistorySplitUploadFailureReturnsInternalServerError(t *testing.T) {