diff --git a/internal/ai/runtime/internal/impl/adapter/tool_result_reducer.go b/internal/ai/runtime/internal/impl/adapter/tool_result_reducer.go
index 73885c8..fd30034 100644
--- a/internal/ai/runtime/internal/impl/adapter/tool_result_reducer.go
+++ b/internal/ai/runtime/internal/impl/adapter/tool_result_reducer.go
@@ -3,6 +3,8 @@ package adapter
 import (
 	"encoding/json"
 	"fmt"
+	"regexp"
+	"strconv"
 	"strings"
 
 	"cs-agent/internal/ai/mcps"
@@ -13,6 +15,14 @@ const (
 	maxToolResultSegments     = 12
 )
 
+var reductionInfoPattern = regexp.MustCompile(`\[tool result reduced: original_length=(\d+), kept_length=(\d+)\]`)
+
+type ReductionInfo struct {
+	Reduced       bool
+	OriginalChars int
+	KeptChars     int
+}
+
 // BuildReducedToolResultSummary returns a bounded text summary for MCP tool results.
 // It keeps the main payload visible to the model while preventing a single large tool
 // response from exhausting too much context.
@@ -36,6 +46,23 @@ func BuildReducedToolResultSummary(result *mcps.ToolCallResult) string {
 	return fmt.Sprintf("%s\n\n[tool result reduced: original_length=%d, kept_length=%d]", truncated, len(runes), maxToolResultSummaryChars)
 }
 
+func ParseReductionInfo(summary string) ReductionInfo {
+	matches := reductionInfoPattern.FindStringSubmatch(strings.TrimSpace(summary))
+	if len(matches) != 3 {
+		return ReductionInfo{}
+	}
+	originalChars, err1 := strconv.Atoi(matches[1])
+	keptChars, err2 := strconv.Atoi(matches[2])
+	if err1 != nil || err2 != nil {
+		return ReductionInfo{}
+	}
+	return ReductionInfo{
+		Reduced:       true,
+		OriginalChars: originalChars,
+		KeptChars:     keptChars,
+	}
+}
+
 func collectToolResultSegments(result *mcps.ToolCallResult) []string {
 	segments := make([]string, 0, len(result.Content)+2)
 	if result.IsError {
diff --git a/internal/ai/runtime/internal/impl/callbacks/agent_trace_handler.go b/internal/ai/runtime/internal/impl/callbacks/agent_trace_handler.go
index 03efdd9..5ace925 100644
--- a/internal/ai/runtime/internal/impl/callbacks/agent_trace_handler.go
+++ b/internal/ai/runtime/internal/impl/callbacks/agent_trace_handler.go
@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	impladapter "cs-agent/internal/ai/runtime/internal/impl/adapter"
 	"cs-agent/internal/pkg/toolx"
 
 	einotool "github.com/cloudwego/eino/components/tool"
@@ -43,6 +44,10 @@ func (h *RuntimeTraceHandler) WrapInvokableToolCall(_ context.Context, endpoint
 			LatencyMs:     time.Since(startedAt).Milliseconds(),
 			Status:        "ok",
 		}
+		reductionInfo := impladapter.ParseReductionInfo(result)
+		item.ResultReduced = reductionInfo.Reduced
+		item.OriginalChars = reductionInfo.OriginalChars
+		item.KeptChars = reductionInfo.KeptChars
 		if tCtx != nil {
 			item.ToolName = strings.TrimSpace(tCtx.Name)
 			if metadata, ok := h.toolMetadataBy[item.ToolName]; ok {
@@ -65,6 +70,9 @@ func (h *RuntimeTraceHandler) WrapInvokableToolCall(_ context.Context, endpoint
 				ToolName:      item.ToolName,
 				Arguments:     item.Arguments,
 				ResultPreview: item.ResultPreview,
+				ResultReduced: item.ResultReduced,
+				OriginalChars: item.OriginalChars,
+				KeptChars:     item.KeptChars,
 				LatencyMs:     item.LatencyMs,
 				Status:        item.Status,
 				ErrorMessage:  item.ErrorMessage,
diff --git a/internal/ai/runtime/internal/impl/callbacks/trace_callback.go b/internal/ai/runtime/internal/impl/callbacks/trace_callback.go
index bb5d686..604265d 100644
--- a/internal/ai/runtime/internal/impl/callbacks/trace_callback.go
+++ b/internal/ai/runtime/internal/impl/callbacks/trace_callback.go
@@ -6,6 +6,9 @@ type ToolTraceItem struct {
 	ToolName      string         `json:"toolName"`
 	Arguments     map[string]any `json:"arguments,omitempty"`
 	ResultPreview string         `json:"resultPreview,omitempty"`
+	ResultReduced bool           `json:"resultReduced,omitempty"`
+	OriginalChars int            `json:"originalChars,omitempty"`
+	KeptChars     int            `json:"keptChars,omitempty"`
 	LatencyMs     int64          `json:"latencyMs,omitempty"`
 	Status        string         `json:"status,omitempty"`
 	ErrorMessage  string         `json:"errorMessage,omitempty"`
@@ -27,6 +30,9 @@ type GraphToolTraceItem struct {
 	ToolName      string         `json:"toolName"`
 	Arguments     map[string]any `json:"arguments,omitempty"`
 	ResultPreview string         `json:"resultPreview,omitempty"`
+	ResultReduced bool           `json:"resultReduced,omitempty"`
+	OriginalChars int            `json:"originalChars,omitempty"`
+	KeptChars     int            `json:"keptChars,omitempty"`
 	LatencyMs     int64          `json:"latencyMs,omitempty"`
 	Status        string         `json:"status,omitempty"`
 	ErrorMessage  string         `json:"errorMessage,omitempty"`