fix: 为 Eino agentic 路径补充 tool_call/tool_result 配对防御中间件

agentic 路径(单代理模式)缺少 toolPairReconciler 和 orphanToolPruner，
当 summarization 截断历史破坏配对后，序列化到 OpenAI API 触发 400
"insufficient tool messages following tool_calls message"。

新增 AgenticMessage 版本的 reconciler 和 pruner，与 classic 路径对齐。

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/multiagent/agentic_orphan_tool_pruner_middleware.go

@@ -0,0 +1,126 @@
+package multiagent
+
+import (
+	"context"
+
+	"github.com/cloudwego/eino/adk"
+	"github.com/cloudwego/eino/schema"
+	"go.uber.org/zap"
+)
+
+// agenticOrphanToolPrunerMiddleware is the AgenticMessage equivalent of
+// orphanToolPrunerMiddleware. It removes user-role messages whose content
+// blocks are exclusively FunctionToolResult entries with CallIDs that do not
+// match any FunctionToolCall in the history.
+//
+// This is a defense-in-depth layer after agenticToolPairReconcilerMiddleware;
+// the reconciler handles the common case (assistant followed by its results)
+// while this pruner catches stray results that appear before their assistant
+// or in non-adjacent positions (e.g. after summarization rewriting).
+type agenticOrphanToolPrunerMiddleware struct {
+	*adk.TypedBaseChatModelAgentMiddleware[*schema.AgenticMessage]
+	logger *zap.Logger
+	phase  string
+}
+
+func newAgenticOrphanToolPrunerMiddleware(logger *zap.Logger, phase string) adk.TypedChatModelAgentMiddleware[*schema.AgenticMessage] {
+	return &agenticOrphanToolPrunerMiddleware{
+		TypedBaseChatModelAgentMiddleware: &adk.TypedBaseChatModelAgentMiddleware[*schema.AgenticMessage]{},
+		logger:                            logger,
+		phase:                             phase,
+	}
+}
+
+func (m *agenticOrphanToolPrunerMiddleware) BeforeModelRewriteState(
+	ctx context.Context,
+	state *adk.TypedChatModelAgentState[*schema.AgenticMessage],
+	mc *adk.TypedModelContext[*schema.AgenticMessage],
+) (context.Context, *adk.TypedChatModelAgentState[*schema.AgenticMessage], error) {
+	_ = mc
+	if m == nil || state == nil || len(state.Messages) == 0 {
+		return ctx, state, nil
+	}
+
+	// Pass 1: collect all provided CallIDs from assistant FunctionToolCall blocks.
+	provided := make(map[string]struct{}, 8)
+	for _, msg := range state.Messages {
+		if msg == nil || msg.Role != schema.AgenticRoleTypeAssistant {
+			continue
+		}
+		for _, block := range msg.ContentBlocks {
+			if block != nil && block.FunctionToolCall != nil && block.FunctionToolCall.CallID != "" {
+				provided[block.FunctionToolCall.CallID] = struct{}{}
+			}
+		}
+	}
+
+	// Fast path: check if any orphan exists.
+	hasOrphan := false
+	for _, msg := range state.Messages {
+		if msg == nil || !isPureAgenticToolResult(msg) {
+			continue
+		}
+		for _, id := range agenticToolResultCallIDs(msg) {
+			if _, ok := provided[id]; !ok {
+				hasOrphan = true
+				break
+			}
+		}
+		if hasOrphan {
+			break
+		}
+	}
+	if !hasOrphan {
+		return ctx, state, nil
+	}
+
+	// Pass 2: build pruned list.
+	pruned := make([]*schema.AgenticMessage, 0, len(state.Messages))
+	var droppedIDs []string
+	var droppedNames []string
+	for _, msg := range state.Messages {
+		if msg == nil {
+			continue
+		}
+		if !isPureAgenticToolResult(msg) {
+			pruned = append(pruned, msg)
+			continue
+		}
+		// Check if ALL result call IDs are orphans. If any is matched, keep the
+		// message (the reconciler already handled partial mismatches).
+		allOrphan := true
+		for _, id := range agenticToolResultCallIDs(msg) {
+			if _, ok := provided[id]; ok {
+				allOrphan = false
+				break
+			}
+		}
+		if allOrphan {
+			for _, block := range msg.ContentBlocks {
+				if block != nil && block.FunctionToolResult != nil {
+					droppedIDs = append(droppedIDs, block.FunctionToolResult.CallID)
+					droppedNames = append(droppedNames, block.FunctionToolResult.Name)
+				}
+			}
+			continue
+		}
+		pruned = append(pruned, msg)
+	}
+
+	if len(droppedIDs) == 0 {
+		return ctx, state, nil
+	}
+	if m.logger != nil {
+		m.logger.Warn("agentic orphan tool messages pruned before model call",
+			zap.String("phase", m.phase),
+			zap.Int("dropped_count", len(droppedIDs)),
+			zap.Strings("dropped_tool_call_ids", droppedIDs),
+			zap.Strings("dropped_tool_names", droppedNames),
+			zap.Int("messages_before", len(state.Messages)),
+			zap.Int("messages_after", len(pruned)),
+		)
+	}
+	ns := *state
+	ns.Messages = pruned
+	return ctx, &ns, nil
+}

internal/multiagent/agentic_tool_pair_reconciler_middleware.go

@@ -0,0 +1,247 @@
+package multiagent
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/cloudwego/eino/adk"
+	"github.com/cloudwego/eino/schema"
+	"go.uber.org/zap"
+)
+
+// agenticToolPairReconcilerMiddleware is the AgenticMessage equivalent of
+// toolPairReconcilerMiddleware. It ensures every assistant FunctionToolCall
+// block is followed by a matching FunctionToolResult message, patching or
+// dropping as needed so the downstream model never receives an unpaired
+// tool-call history.
+//
+// In the AgenticMessage protocol:
+//   - Assistant tool calls: Role=AgenticRoleTypeAssistant with FunctionToolCall content blocks.
+//   - Tool results: Role=AgenticRoleTypeUser with FunctionToolResult content blocks.
+//
+// This middleware runs after summarization which may truncate history and
+// break pairings.
+type agenticToolPairReconcilerMiddleware struct {
+	*adk.TypedBaseChatModelAgentMiddleware[*schema.AgenticMessage]
+	logger *zap.Logger
+	phase  string
+}
+
+func newAgenticToolPairReconcilerMiddleware(logger *zap.Logger, phase string) adk.TypedChatModelAgentMiddleware[*schema.AgenticMessage] {
+	return &agenticToolPairReconcilerMiddleware{
+		TypedBaseChatModelAgentMiddleware: &adk.TypedBaseChatModelAgentMiddleware[*schema.AgenticMessage]{},
+		logger:                            logger,
+		phase:                             phase,
+	}
+}
+
+func (m *agenticToolPairReconcilerMiddleware) BeforeModelRewriteState(
+	ctx context.Context,
+	state *adk.TypedChatModelAgentState[*schema.AgenticMessage],
+	mc *adk.TypedModelContext[*schema.AgenticMessage],
+) (context.Context, *adk.TypedChatModelAgentState[*schema.AgenticMessage], error) {
+	_ = mc
+	if m == nil || state == nil || len(state.Messages) == 0 {
+		return ctx, state, nil
+	}
+
+	usedIDs := make(map[string]struct{}, 16)
+	changed := false
+	patched := 0
+	dropped := 0
+	out := make([]*schema.AgenticMessage, 0, len(state.Messages))
+
+	for i := 0; i < len(state.Messages); {
+		msg := state.Messages[i]
+		if msg == nil {
+			changed = true
+			i++
+			continue
+		}
+
+		calls := agenticFunctionToolCalls(msg)
+
+		// Non-assistant or assistant without tool calls — but check for orphan
+		// tool-result messages (user role with only FunctionToolResult blocks).
+		if len(calls) == 0 {
+			if isPureAgenticToolResult(msg) {
+				// Orphan tool result not preceded by its assistant; drop it.
+				changed = true
+				dropped++
+				i++
+				continue
+			}
+			out = append(out, msg)
+			i++
+			continue
+		}
+
+		// Deduplicate / fix empty call IDs.
+		idsChanged := false
+		for ci := range calls {
+			id := calls[ci].CallID
+			_, duplicate := usedIDs[id]
+			if id == "" || duplicate {
+				base := fmt.Sprintf("patched_agentic_call_%d_%d", i, ci)
+				id = base
+				for suffix := 1; ; suffix++ {
+					if _, exists := usedIDs[id]; !exists {
+						break
+					}
+					id = fmt.Sprintf("%s_%d", base, suffix)
+				}
+				calls[ci].CallID = id
+				idsChanged = true
+				changed = true
+			}
+			usedIDs[id] = struct{}{}
+		}
+
+		assistant := msg
+		if idsChanged {
+			assistant = cloneAgenticMessageWithCalls(msg, calls)
+		}
+		out = append(out, assistant)
+
+		// Build expected set.
+		expected := make(map[string]*schema.FunctionToolCall, len(calls))
+		for ci := range calls {
+			expected[calls[ci].CallID] = calls[ci]
+		}
+
+		// Consume following tool-result messages.
+		results := make(map[string]*schema.AgenticMessage, len(calls))
+		j := i + 1
+		for j < len(state.Messages) {
+			next := state.Messages[j]
+			if next == nil {
+				changed = true
+				j++
+				continue
+			}
+			if !isPureAgenticToolResult(next) {
+				break
+			}
+			resultCallIDs := agenticToolResultCallIDs(next)
+			consumed := false
+			for _, rid := range resultCallIDs {
+				if _, wanted := expected[rid]; !wanted {
+					continue
+				}
+				if _, dup := results[rid]; dup {
+					continue
+				}
+				results[rid] = next
+				consumed = true
+			}
+			if !consumed {
+				changed = true
+				dropped++
+			}
+			j++
+		}
+
+		// Emit results in call order, patching missing ones.
+		for _, tc := range calls {
+			if result, ok := results[tc.CallID]; ok {
+				out = append(out, result)
+				continue
+			}
+			out = append(out, makeAgenticPatchedToolResult(tc.CallID, tc.Name))
+			changed = true
+			patched++
+		}
+		i = j
+	}
+
+	if !changed {
+		return ctx, state, nil
+	}
+	if m.logger != nil {
+		m.logger.Warn("agentic tool-call/result pairs reconciled before model call",
+			zap.String("phase", m.phase),
+			zap.Int("patched_results", patched),
+			zap.Int("dropped_results", dropped),
+			zap.Int("messages_before", len(state.Messages)),
+			zap.Int("messages_after", len(out)),
+		)
+	}
+	ns := *state
+	ns.Messages = out
+	return ctx, &ns, nil
+}
+
+// agenticFunctionToolCalls extracts FunctionToolCall pointers from an
+// assistant message's content blocks. Returns nil for non-assistant messages.
+func agenticFunctionToolCalls(msg *schema.AgenticMessage) []*schema.FunctionToolCall {
+	if msg == nil || msg.Role != schema.AgenticRoleTypeAssistant {
+		return nil
+	}
+	var out []*schema.FunctionToolCall
+	for _, block := range msg.ContentBlocks {
+		if block != nil && block.FunctionToolCall != nil {
+			out = append(out, block.FunctionToolCall)
+		}
+	}
+	return out
+}
+
+// isPureAgenticToolResult returns true when the message is a user-role
+// message whose content blocks are exclusively FunctionToolResult entries.
+func isPureAgenticToolResult(msg *schema.AgenticMessage) bool {
+	if msg == nil || msg.Role != schema.AgenticRoleTypeUser || len(msg.ContentBlocks) == 0 {
+		return false
+	}
+	for _, block := range msg.ContentBlocks {
+		if block == nil {
+			continue
+		}
+		if block.FunctionToolResult == nil {
+			return false
+		}
+	}
+	return true
+}
+
+// agenticToolResultCallIDs extracts all CallIDs from FunctionToolResult blocks.
+func agenticToolResultCallIDs(msg *schema.AgenticMessage) []string {
+	if msg == nil {
+		return nil
+	}
+	var ids []string
+	for _, block := range msg.ContentBlocks {
+		if block != nil && block.FunctionToolResult != nil && block.FunctionToolResult.CallID != "" {
+			ids = append(ids, block.FunctionToolResult.CallID)
+		}
+	}
+	return ids
+}
+
+func cloneAgenticMessageWithCalls(msg *schema.AgenticMessage, calls []*schema.FunctionToolCall) *schema.AgenticMessage {
+	cloned := *msg
+	cloned.ContentBlocks = make([]*schema.ContentBlock, 0, len(msg.ContentBlocks))
+	callIdx := 0
+	for _, block := range msg.ContentBlocks {
+		if block != nil && block.FunctionToolCall != nil && callIdx < len(calls) {
+			cloned.ContentBlocks = append(cloned.ContentBlocks, schema.NewContentBlock(calls[callIdx]))
+			callIdx++
+		} else {
+			cloned.ContentBlocks = append(cloned.ContentBlocks, block)
+		}
+	}
+	return &cloned
+}
+
+func makeAgenticPatchedToolResult(callID, name string) *schema.AgenticMessage {
+	return &schema.AgenticMessage{
+		Role: schema.AgenticRoleTypeUser,
+		ContentBlocks: []*schema.ContentBlock{schema.NewContentBlock(&schema.FunctionToolResult{
+			CallID: callID,
+			Name:   name,
+			Content: []*schema.FunctionToolResultContentBlock{{
+				Type: schema.FunctionToolResultContentBlockTypeText,
+				Text: &schema.UserInputText{Text: patchedMissingToolResult},
+			}},
+		})},
+	}
+}

internal/multiagent/agentic_tool_pair_reconciler_middleware_test.go

@@ -0,0 +1,157 @@
+package multiagent
+
+import (
+	"context"
+	"testing"
+
+	"github.com/cloudwego/eino/adk"
+	"github.com/cloudwego/eino/schema"
+)
+
+func TestAgenticToolPairReconcilerPatchesMissing(t *testing.T) {
+	t.Parallel()
+	mw := newAgenticToolPairReconcilerMiddleware(nil, "test")
+	state := &adk.TypedChatModelAgentState[*schema.AgenticMessage]{
+		Messages: []*schema.AgenticMessage{
+			agenticAssistantToolCall("c1", "search", `{"q":"x"}`),
+			agenticAssistantToolCall("c2", "execute", `{"cmd":"ls"}`),
+			// c1 result present, c2 missing
+			agenticToolResult("c1", "search", "found it"),
+		},
+	}
+	_, out, err := mw.BeforeModelRewriteState(context.Background(), state, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Expected: assistant(c1) -> result(c1) -> assistant(c2) -> patched_result(c2)
+	if len(out.Messages) != 4 {
+		t.Fatalf("messages = %d, want 4", len(out.Messages))
+	}
+	// c1 assistant
+	if calls := agenticFunctionToolCalls(out.Messages[0]); len(calls) != 1 || calls[0].CallID != "c1" {
+		t.Fatal("msg[0] should be assistant(c1)")
+	}
+	// c1 result
+	if ids := agenticToolResultCallIDs(out.Messages[1]); len(ids) != 1 || ids[0] != "c1" {
+		t.Fatal("msg[1] should be result(c1)")
+	}
+	// c2 assistant
+	if calls := agenticFunctionToolCalls(out.Messages[2]); len(calls) != 1 || calls[0].CallID != "c2" {
+		t.Fatal("msg[2] should be assistant(c2)")
+	}
+	// c2 patched result
+	if ids := agenticToolResultCallIDs(out.Messages[3]); len(ids) != 1 || ids[0] != "c2" {
+		t.Fatal("msg[3] should be patched result(c2)")
+	}
+	resultText := out.Messages[3].ContentBlocks[0].FunctionToolResult.Content[0].Text.Text
+	if resultText != patchedMissingToolResult {
+		t.Fatalf("patched text = %q", resultText)
+	}
+}
+
+func TestAgenticToolPairReconcilerDropsOrphan(t *testing.T) {
+	t.Parallel()
+	mw := newAgenticToolPairReconcilerMiddleware(nil, "test")
+	state := &adk.TypedChatModelAgentState[*schema.AgenticMessage]{
+		Messages: []*schema.AgenticMessage{
+			// Orphan tool result with no preceding assistant
+			agenticToolResult("orphan", "deleted_tool", "stale data"),
+			{Role: schema.AgenticRoleTypeUser, ContentBlocks: []*schema.ContentBlock{
+				schema.NewContentBlock(&schema.UserInputText{Text: "hello"}),
+			}},
+		},
+	}
+	_, out, err := mw.BeforeModelRewriteState(context.Background(), state, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(out.Messages) != 1 {
+		t.Fatalf("messages = %d, want 1 (orphan dropped)", len(out.Messages))
+	}
+	if out.Messages[0].ContentBlocks[0].UserInputText == nil {
+		t.Fatal("remaining message should be the user text")
+	}
+}
+
+func TestAgenticToolPairReconcilerNoopWhenPaired(t *testing.T) {
+	t.Parallel()
+	mw := newAgenticToolPairReconcilerMiddleware(nil, "test")
+	state := &adk.TypedChatModelAgentState[*schema.AgenticMessage]{
+		Messages: []*schema.AgenticMessage{
+			agenticAssistantToolCall("c1", "search", `{}`),
+			agenticToolResult("c1", "search", "ok"),
+		},
+	}
+	_, out, err := mw.BeforeModelRewriteState(context.Background(), state, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// Should return original state unchanged
+	if &out.Messages[0] == &state.Messages[0] {
+		// pointer equality on slice — state not cloned
+	}
+	if len(out.Messages) != 2 {
+		t.Fatalf("messages = %d, want 2", len(out.Messages))
+	}
+}
+
+func TestAgenticToolPairReconcilerFixesEmptyCallID(t *testing.T) {
+	t.Parallel()
+	mw := newAgenticToolPairReconcilerMiddleware(nil, "test")
+	state := &adk.TypedChatModelAgentState[*schema.AgenticMessage]{
+		Messages: []*schema.AgenticMessage{
+			{
+				Role: schema.AgenticRoleTypeAssistant,
+				ContentBlocks: []*schema.ContentBlock{schema.NewContentBlock(&schema.FunctionToolCall{
+					CallID: "", Name: "search", Arguments: `{}`,
+				})},
+			},
+		},
+	}
+	_, out, err := mw.BeforeModelRewriteState(context.Background(), state, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	calls := agenticFunctionToolCalls(out.Messages[0])
+	if len(calls) != 1 || calls[0].CallID == "" {
+		t.Fatalf("empty call ID should be patched, got %q", calls[0].CallID)
+	}
+}
+
+func TestAgenticOrphanToolPrunerRemovesOrphan(t *testing.T) {
+	t.Parallel()
+	mw := newAgenticOrphanToolPrunerMiddleware(nil, "test")
+	state := &adk.TypedChatModelAgentState[*schema.AgenticMessage]{
+		Messages: []*schema.AgenticMessage{
+			agenticAssistantToolCall("c1", "search", `{}`),
+			agenticToolResult("c1", "search", "ok"),
+			// Orphan: no assistant has call_id "c_orphan"
+			agenticToolResult("c_orphan", "deleted", "stale"),
+		},
+	}
+	_, out, err := mw.BeforeModelRewriteState(context.Background(), state, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(out.Messages) != 2 {
+		t.Fatalf("messages = %d, want 2 (orphan pruned)", len(out.Messages))
+	}
+}
+
+func TestAgenticOrphanToolPrunerNoopWhenClean(t *testing.T) {
+	t.Parallel()
+	mw := newAgenticOrphanToolPrunerMiddleware(nil, "test")
+	state := &adk.TypedChatModelAgentState[*schema.AgenticMessage]{
+		Messages: []*schema.AgenticMessage{
+			agenticAssistantToolCall("c1", "search", `{}`),
+			agenticToolResult("c1", "search", "ok"),
+		},
+	}
+	_, out, err := mw.BeforeModelRewriteState(context.Background(), state, nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(out.Messages) != 2 {
+		t.Fatalf("messages = %d, want 2", len(out.Messages))
+	}
+}

internal/multiagent/eino_agentic_chat_model_tail_middleware.go

@@ -20,8 +20,13 @@ func appendEinoAgenticChatModelTailMiddlewares(
 	handlers = append(handlers, newAgenticSystemMessageNormalizerMiddleware(cfg.logger, cfg.phase))
 	handlers = append(handlers, newAgenticContinuationUserDedupMiddleware(cfg.logger, cfg.phase))
 	if cfg.agenticSummarization != nil {
+		handlers = append(handlers, newAgenticToolPairReconcilerMiddleware(cfg.logger, cfg.phase+"_pre_summarization"))
 		handlers = append(handlers, cfg.agenticSummarization)
 	}
+	handlers = append(handlers, newAgenticToolPairReconcilerMiddleware(cfg.logger, cfg.phase))
+	if !cfg.skipOrphanPruner {
+		handlers = append(handlers, newAgenticOrphanToolPrunerMiddleware(cfg.logger, cfg.phase))
+	}
 	if !cfg.skipTrace && cfg.trace != nil {
 		if capMw := newAgenticModelFacingTraceMiddleware(cfg.trace); capMw != nil {
 			handlers = append(handlers, capMw)

internal/multiagent/eino_agentic_chat_model_tail_middleware_test.go

@@ -106,7 +106,8 @@ func TestAppendEinoAgenticChatModelTailMiddlewares(t *testing.T) {
 		phase: "agentic",
 		trace: holder,
 	})
-	if len(handlers) != 3 {
+	// system + continuation + reconciler + orphan_pruner + trace
-		t.Fatalf("handlers = %d, want system + continuation + trace", len(handlers))
+	if len(handlers) != 5 {
+		t.Fatalf("handlers = %d, want system + continuation + reconciler + orphan_pruner + trace", len(handlers))
 	}
 }