fix(context): 细化 micro compact 保留策略

internal/context/builder_test.go

@@ -399,8 +399,8 @@ func TestDefaultBuilderBuildAppliesMicroCompactAfterTrim(t *testing.T) {
 	if len(got.Messages) != len(messages) {
 		t.Fatalf("expected builder output to keep message count, got %d want %d", len(got.Messages), len(messages))
 	}
-	if renderDisplayParts(got.Messages[2].Parts) != microCompactClearedMessage {
-		t.Fatalf("expected builder output to clear older tool result, got %q", renderDisplayParts(got.Messages[2].Parts))
+	if !strings.Contains(renderDisplayParts(got.Messages[2].Parts), "[summary] filesystem_read_file") {
+		t.Fatalf("expected builder output to summarize older tool result, got %q", renderDisplayParts(got.Messages[2].Parts))
 	}
 	if renderDisplayParts(got.Messages[4].Parts) != "recent bash result" {
 		t.Fatalf("expected recent tool result to stay visible, got %q", renderDisplayParts(got.Messages[4].Parts))
@@ -513,8 +513,8 @@ func TestDefaultBuilderBuildRespectsExplicitPinCheckerOverride(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
-	if renderDisplayParts(got.Messages[2].Parts) != microCompactClearedMessage {
-		t.Fatalf("expected explicit noop pin checker to allow compaction, got %q", renderDisplayParts(got.Messages[2].Parts))
+	if !strings.Contains(renderDisplayParts(got.Messages[2].Parts), "[summary] filesystem_write_file") {
+		t.Fatalf("expected explicit noop pin checker to allow compaction into summary, got %q", renderDisplayParts(got.Messages[2].Parts))
 	}
 }
 
@@ -1116,8 +1116,8 @@ func TestNewConfiguredBuilder(t *testing.T) {
 		if err != nil {
 			t.Fatalf("Build() error = %v", err)
 		}
-		if renderDisplayParts(got.Messages[2].Parts) != microCompactClearedMessage {
-			t.Fatalf("expected noop pin checker to allow compaction, got %q", renderDisplayParts(got.Messages[2].Parts))
+		if !strings.Contains(renderDisplayParts(got.Messages[2].Parts), "[summary] filesystem_write_file") {
+			t.Fatalf("expected noop pin checker to allow compaction into summary, got %q", renderDisplayParts(got.Messages[2].Parts))
 		}
 	})
 

internal/context/microcompact.go

@@ -1,7 +1,9 @@
 package context
 
 import (
+	"strconv"
 	"strings"
+	"unicode/utf8"
 
 	"neo-code/internal/config"
 	"neo-code/internal/context/internalcompact"
@@ -235,32 +237,63 @@ func summarizeOrClear(
 	toolNames map[string]string,
 	summarizers MicroCompactSummarizerSource,
 ) string {
-	if summarizers == nil {
-		return microCompactClearedMessage
-	}
-
 	callID := strings.TrimSpace(message.ToolCallID)
 	toolName, ok := toolNames[callID]
 	if !ok {
 		return microCompactClearedMessage
 	}
 
-	summarizer := summarizers.MicroCompactSummarizer(toolName)
-	if summarizer == nil {
-		return microCompactClearedMessage
+	if summarizers != nil {
+		summarizer := summarizers.MicroCompactSummarizer(toolName)
+		if summarizer != nil {
+			summary := summarizer(content, message.ToolMetadata, message.IsError)
+			if summary != "" {
+				summary = sanitizeMicroCompactSummary(summary)
+				if summary != "" {
+					return summary
+				}
+			}
+		}
 	}
 
-	summary := summarizer(content, message.ToolMetadata, message.IsError)
-	if summary == "" {
-		return microCompactClearedMessage
-	}
-	summary = sanitizeMicroCompactSummary(summary)
+	summary := sanitizeMicroCompactSummary(fallbackSummary(toolName, content))
 	if summary == "" {
 		return microCompactClearedMessage
 	}
 	return summary
 }
 
+// fallbackSummary 为缺少专用摘要器的工具生成最小可读摘要，避免静默清空历史。
+func fallbackSummary(toolName string, content string) string {
+	trimmedName := strings.TrimSpace(toolName)
+	if trimmedName == "" {
+		return ""
+	}
+
+	parts := []string{
+		"[summary]",
+		trimmedName,
+		"lines=" + strconv.Itoa(stableLineCount(content)),
+		"chars=" + strconv.Itoa(utf8.RuneCountInString(content)),
+	}
+	return strings.Join(parts, " ")
+}
+
+// stableLineCount 统计文本行数；空文本返回 0，末尾换行不会产生额外空行计数。
+func stableLineCount(text string) int {
+	if text == "" {
+		return 0
+	}
+	count := strings.Count(text, "\n") + 1
+	if strings.HasSuffix(text, "\n") {
+		count--
+	}
+	if count < 0 {
+		return 0
+	}
+	return count
+}
+
 // sanitizeMicroCompactSummary 对 summarizer 输出做最终净化与限长，避免把不安全文本直接回灌上下文。
 func sanitizeMicroCompactSummary(summary string) string {
 	trimmed := strings.TrimSpace(summary)

internal/context/microcompact_summarizer_test.go

@@ -78,8 +78,8 @@ func TestMicroCompactWithSummarizerProducesSummary(t *testing.T) {
 	}
 }
 
-// TestMicroCompactWithoutSummarizerFallsBackToClear 验证未注册 summarizer 的工具仍使用清除占位。
-func TestMicroCompactWithoutSummarizerFallsBackToClear(t *testing.T) {
+// TestMicroCompactWithoutSummarizerFallsBackToSummary 验证未注册 summarizer 的工具使用通用兜底摘要。
+func TestMicroCompactWithoutSummarizerFallsBackToSummary(t *testing.T) {
 	t.Parallel()
 
 	messages := []providertypes.Message{
@@ -121,9 +121,12 @@ func TestMicroCompactWithoutSummarizerFallsBackToClear(t *testing.T) {
 		nil,
 	)
 
-	// read_file 没有 summarizer，应回退到清除
-	if renderDisplayParts(got[2].Parts) != microCompactClearedMessage {
-		t.Fatalf("expected cleared placeholder for read_file without summarizer, got %q", renderDisplayParts(got[2].Parts))
+	summary := renderDisplayParts(got[2].Parts)
+	if summary == microCompactClearedMessage {
+		t.Fatalf("expected fallback summary for read_file without summarizer, got cleared placeholder")
+	}
+	if !strings.Contains(summary, "[summary] filesystem_read_file") {
+		t.Fatalf("expected fallback summary to include tool name, got %q", summary)
 	}
 }
 
@@ -176,14 +179,17 @@ func TestMicroCompactMixedSpanWithSummarizer(t *testing.T) {
 	if !strings.Contains(renderDisplayParts(got[2].Parts), "[summary]") {
 		t.Fatalf("expected bash summary in old span, got %q", renderDisplayParts(got[2].Parts))
 	}
-	// call-2 read_file 在旧 span，没有 summarizer，应清除
-	if renderDisplayParts(got[3].Parts) != microCompactClearedMessage {
-		t.Fatalf("expected read_file cleared in old span, got %q", renderDisplayParts(got[3].Parts))
+	summary := renderDisplayParts(got[3].Parts)
+	if summary == microCompactClearedMessage {
+		t.Fatalf("expected read_file fallback summary in old span, got cleared placeholder")
+	}
+	if !strings.Contains(summary, "[summary] filesystem_read_file") {
+		t.Fatalf("expected read_file fallback summary to include tool name, got %q", summary)
 	}
 }
 
-// TestMicroCompactSummarizerReturnsEmptyFallsBackToClear 验证 summarizer 返回空字符串时回退到清除。
-func TestMicroCompactSummarizerReturnsEmptyFallsBackToClear(t *testing.T) {
+// TestMicroCompactSummarizerReturnsEmptyFallsBackToSummary 验证 summarizer 返回空字符串时回退到通用摘要。
+func TestMicroCompactSummarizerReturnsEmptyFallsBackToSummary(t *testing.T) {
 	t.Parallel()
 
 	messages := []providertypes.Message{
@@ -224,8 +230,12 @@ func TestMicroCompactSummarizerReturnsEmptyFallsBackToClear(t *testing.T) {
 		nil,
 	)
 
-	if renderDisplayParts(got[2].Parts) != microCompactClearedMessage {
-		t.Fatalf("expected cleared fallback when summarizer returns empty, got %q", renderDisplayParts(got[2].Parts))
+	summary := renderDisplayParts(got[2].Parts)
+	if summary == microCompactClearedMessage {
+		t.Fatalf("expected fallback summary when summarizer returns empty, got cleared placeholder")
+	}
+	if !strings.Contains(summary, "[summary] bash") {
+		t.Fatalf("expected fallback summary to include tool name, got %q", summary)
 	}
 }
 
@@ -244,6 +254,26 @@ func TestSummarizeOrClearWithNilSummarizers(t *testing.T) {
 	}
 }
 
+func TestSummarizeOrClearFallsBackWithoutRegisteredSummarizer(t *testing.T) {
+	t.Parallel()
+
+	got := summarizeOrClear(
+		providertypes.Message{ToolCallID: "call-1"},
+		"first line\nsecond line",
+		map[string]string{"call-1": "mcp.github.issue"},
+		nil,
+	)
+	if got == microCompactClearedMessage {
+		t.Fatalf("expected fallback summary for MCP tool, got cleared placeholder")
+	}
+	if !strings.Contains(got, "[summary] mcp.github.issue") {
+		t.Fatalf("expected MCP tool name in fallback summary, got %q", got)
+	}
+	if !strings.Contains(got, "lines=2") {
+		t.Fatalf("expected line count in fallback summary, got %q", got)
+	}
+}
+
 // TestSummarizeOrClearWithToolNamesLookup 验证 toolNames map 查找工具名。
 func TestSummarizeOrClearWithToolNamesLookup(t *testing.T) {
 	t.Parallel()
@@ -321,8 +351,11 @@ func TestSummarizeOrClearSanitizationEmptyFallback(t *testing.T) {
 		},
 	)
 
-	if got != microCompactClearedMessage {
-		t.Fatalf("expected cleared fallback when sanitized summary is empty, got %q", got)
+	if got == microCompactClearedMessage {
+		t.Fatalf("expected fallback summary when sanitized summary is empty, got cleared placeholder")
+	}
+	if !strings.Contains(got, "[summary] bash") {
+		t.Fatalf("expected fallback summary to include tool name, got %q", got)
 	}
 }