feat(adk): add agent team demo

adk/README.md

@@ -37,6 +37,7 @@ This directory provides examples for Eino ADK:
   - `middlewares`
     - `skill`: loads Agent skills from filesystem.
     - `dynamictool/toolsearch`: dynamically retrieves and injects relevant tools from a large tool set.
+    - `team`: how to create agent teams from scratch.
   - `common`
     - `tool/graphtool`: wraps Graph/Chain/Workflow as Agent tools.
     - `model`, `prints`, `store`, `trace`: shared helpers used by examples.

adk/intro/http-sse-service/go.mod

@@ -5,7 +5,7 @@ go 1.24.9
 replace github.com/cloudwego/eino-examples => ../../..
 
 require (
-	github.com/cloudwego/eino v0.9.0-beta.1
+	github.com/cloudwego/eino v0.9.9
 	github.com/cloudwego/eino-examples v0.0.0-00010101000000-000000000000
 	github.com/cloudwego/hertz v0.10.3
 	github.com/hertz-contrib/sse v0.1.0
@@ -19,9 +19,9 @@ require (
 	github.com/bytedance/sonic/loader v0.5.0 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/cloudwego/base64x v0.1.6 // indirect
-	github.com/cloudwego/eino-ext/components/model/ark v0.1.65 // indirect
-	github.com/cloudwego/eino-ext/components/model/openai v0.1.12 // indirect
-	github.com/cloudwego/eino-ext/libs/acl/openai v0.1.16 // indirect
+	github.com/cloudwego/eino-ext/components/model/ark v0.1.68 // indirect
+	github.com/cloudwego/eino-ext/components/model/openai v0.1.13 // indirect
+	github.com/cloudwego/eino-ext/libs/acl/openai v0.1.17 // indirect
 	github.com/cloudwego/gopkg v0.1.4 // indirect
 	github.com/cloudwego/netpoll v0.7.0 // indirect
 	github.com/dustin/go-humanize v1.0.1 // indirect
@@ -49,7 +49,7 @@ require (
 	github.com/tidwall/pretty v1.2.1 // indirect
 	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
 	github.com/volcengine/volc-sdk-golang v1.0.199 // indirect
-	github.com/volcengine/volcengine-go-sdk v1.2.27 // indirect
+	github.com/volcengine/volcengine-go-sdk v1.2.28 // indirect
 	github.com/wk8/go-ordered-map/v2 v2.1.8 // indirect
 	github.com/yargevad/filepathx v1.0.0 // indirect
 	golang.org/x/arch v0.19.0 // indirect

adk/intro/http-sse-service/go.sum

@@ -108,12 +108,16 @@ github.com/cloudwego/eino v0.9.0-alpha.18 h1:xBd6wReRd8a4kcICvtVAaDZywMQ5Yw+ip+x
 github.com/cloudwego/eino v0.9.0-alpha.18/go.mod h1:OBD1mrkfkt/pJa4rkg1P0VnaMeOVl7l8IAdEqY//3IQ=
 github.com/cloudwego/eino v0.9.0-alpha.22/go.mod h1:OBD1mrkfkt/pJa4rkg1P0VnaMeOVl7l8IAdEqY//3IQ=
 github.com/cloudwego/eino v0.9.0-alpha.24/go.mod h1:OBD1mrkfkt/pJa4rkg1P0VnaMeOVl7l8IAdEqY//3IQ=
+github.com/cloudwego/eino v0.9.9/go.mod h1:OBD1mrkfkt/pJa4rkg1P0VnaMeOVl7l8IAdEqY//3IQ=
 github.com/cloudwego/eino-ext/components/model/ark v0.1.65 h1:52ukXVU9ntToTa36SwI8be81qskGkpUEZraIFOf0wqk=
 github.com/cloudwego/eino-ext/components/model/ark v0.1.65/go.mod h1:aabMR15RTXBSi9Eu13CWavzE+no5BQO4FJUEEdqImbg=
+github.com/cloudwego/eino-ext/components/model/ark v0.1.68/go.mod h1:IctHLV+EmEhf3o2fBw0N873mLIyNlEAAGcEpUGEQdvk=
 github.com/cloudwego/eino-ext/components/model/openai v0.1.12 h1:vcwNXeT7bpaXMNwUhtcHZwMYY8II2jAihuooyivmEZ0=
 github.com/cloudwego/eino-ext/components/model/openai v0.1.12/go.mod h1:ve/+/hLZMvxD5AieQ355xHIFhAZVlsG4rdwTnE16aQU=
+github.com/cloudwego/eino-ext/components/model/openai v0.1.13/go.mod h1:mgIoqYYOc0eECCqvLbEYpOJrQNTNxkwXzSJzFU+v5sQ=
 github.com/cloudwego/eino-ext/libs/acl/openai v0.1.16 h1:q242n5P5Tx3a2QLaBmkfEpfRs/o17Ac6u3EAgItEEOc=
 github.com/cloudwego/eino-ext/libs/acl/openai v0.1.16/go.mod h1:p+l0zBB0GjjX8HTlbTs3g3KfUFwZC11bsCGZOXW/3L0=
+github.com/cloudwego/eino-ext/libs/acl/openai v0.1.17/go.mod h1:Zkcx6DPTR2NfWmtSXbhItswGw6hqUezNPhNcke0pOG8=
 github.com/cloudwego/gopkg v0.1.4 h1:EoQiCG4sTonTPHxOGE0VlQs+sQR+Hsi2uN0qqwu8O50=
 github.com/cloudwego/gopkg v0.1.4/go.mod h1:FQuXsRWRsSqJLsMVd5SYzp8/Z1y5gXKnVvRrWUOsCMI=
 github.com/cloudwego/hertz v0.10.3 h1:NFcQAjouVJsod79XPLC/PaFfHgjMTYbiErmW+vGBi8A=
@@ -514,6 +518,7 @@ github.com/volcengine/volc-sdk-golang v1.0.199/go.mod h1:stZX+EPgv1vF4nZwOlEe8iG
 github.com/volcengine/volcengine-go-sdk v1.2.9 h1:du2gnImtyWXKkQFnJW/GXCs+UBibGGOXIbP1Ams2pB8=
 github.com/volcengine/volcengine-go-sdk v1.2.9/go.mod h1:oxoVo+A17kvkwPkIeIHPVLjSw7EQAm+l/Vau1YGHN+A=
 github.com/volcengine/volcengine-go-sdk v1.2.27/go.mod h1:oxoVo+A17kvkwPkIeIHPVLjSw7EQAm+l/Vau1YGHN+A=
+github.com/volcengine/volcengine-go-sdk v1.2.28/go.mod h1:oxoVo+A17kvkwPkIeIHPVLjSw7EQAm+l/Vau1YGHN+A=
 github.com/wk8/go-ordered-map/v2 v2.1.8 h1:5h/BUHu93oj4gIdvHHHGsScSTMijfx5PeYkE/fJgbpc=
 github.com/wk8/go-ordered-map/v2 v2.1.8/go.mod h1:5nJHM5DyteebpVlHnWMV0rPz6Zp7+xBAnxjb1X5vnTw=
 github.com/x-cray/logrus-prefixed-formatter v0.5.2 h1:00txxvfBM9muc0jiLIEAkAcIMJzfthRT6usrui8uGmg=

adk/middlewares/team/backend.go

@@ -0,0 +1,174 @@
+/*
+ * Copyright 2026 CloudWeGo Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/cloudwego/eino/adk/middlewares/filesystem"
+	"github.com/cloudwego/eino/adk/prebuilt/team"
+)
+
+// ---------------------------------------------------------------------------
+// File-based Backend that persists data to the filesystem
+// ---------------------------------------------------------------------------
+
+type fileBackend struct {
+	baseDir       string
+	mu            sync.RWMutex
+	seededInboxes map[string]bool
+}
+
+func newFileBackend(baseDir string) *fileBackend {
+	if baseDir == "" {
+		baseDir = os.TempDir()
+	}
+	return &fileBackend{
+		baseDir:       baseDir,
+		seededInboxes: make(map[string]bool),
+	}
+}
+
+func (b *fileBackend) LsInfo(_ context.Context, req *team.LsInfoRequest) ([]team.FileInfo, error) {
+	entries, err := os.ReadDir(req.Path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, nil
+		}
+		return nil, fmt.Errorf("read dir %s: %w", req.Path, err)
+	}
+
+	var result []team.FileInfo
+	for _, entry := range entries {
+		info, err := entry.Info()
+		if err != nil {
+			continue
+		}
+		result = append(result, team.FileInfo{
+			Path:       filepath.Join(req.Path, entry.Name()),
+			IsDir:      entry.IsDir(),
+			Size:       info.Size(),
+			ModifiedAt: info.ModTime().UTC().Format(time.RFC3339),
+		})
+	}
+	return result, nil
+}
+
+func (b *fileBackend) Read(_ context.Context, req *team.ReadRequest) (*filesystem.FileContent, error) {
+	data, err := os.ReadFile(req.FilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil, fmt.Errorf("file not found: %s", req.FilePath)
+		}
+		return nil, fmt.Errorf("read file %s: %w", req.FilePath, err)
+	}
+	return &filesystem.FileContent{Content: string(data)}, nil
+}
+
+func (b *fileBackend) Write(_ context.Context, req *team.WriteRequest) error {
+	dir := filepath.Dir(req.FilePath)
+	if err := os.MkdirAll(dir, 0755); err != nil {
+		return fmt.Errorf("create dir %s: %w", dir, err)
+	}
+
+	content := req.Content
+
+	// Atomic replace: write to a temp file in the same directory, fsync, then
+	// rename over the target. This satisfies the team.Backend durability contract
+	// so a crash mid-write can never leave a truncated config.json or inbox.
+	tmp, err := os.CreateTemp(dir, "."+filepath.Base(req.FilePath)+".tmp-*")
+	if err != nil {
+		return fmt.Errorf("create temp file for %s: %w", req.FilePath, err)
+	}
+	tmpName := tmp.Name()
+	// Best-effort cleanup if we bail out before the rename succeeds.
+	defer func() { _ = os.Remove(tmpName) }()
+
+	if _, err := tmp.WriteString(content); err != nil {
+		_ = tmp.Close()
+		return fmt.Errorf("write temp file for %s: %w", req.FilePath, err)
+	}
+	if err := tmp.Sync(); err != nil {
+		_ = tmp.Close()
+		return fmt.Errorf("sync temp file for %s: %w", req.FilePath, err)
+	}
+	if err := tmp.Close(); err != nil {
+		return fmt.Errorf("close temp file for %s: %w", req.FilePath, err)
+	}
+	if err := os.Chmod(tmpName, 0644); err != nil {
+		return fmt.Errorf("chmod temp file for %s: %w", req.FilePath, err)
+	}
+	if err := os.Rename(tmpName, req.FilePath); err != nil {
+		return fmt.Errorf("rename temp file to %s: %w", req.FilePath, err)
+	}
+	return nil
+}
+
+func (b *fileBackend) Delete(_ context.Context, req *team.DeleteRequest) error {
+	info, err := os.Stat(req.FilePath)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return fmt.Errorf("stat %s: %w", req.FilePath, err)
+	}
+
+	if info.IsDir() {
+		if err := os.RemoveAll(req.FilePath); err != nil {
+			return fmt.Errorf("remove dir %s: %w", req.FilePath, err)
+		}
+	} else {
+		if err := os.Remove(req.FilePath); err != nil {
+			return fmt.Errorf("remove file %s: %w", req.FilePath, err)
+		}
+	}
+	return nil
+}
+
+func (b *fileBackend) Exists(_ context.Context, path string) (bool, error) {
+	_, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil
+		}
+		return false, fmt.Errorf("stat %s: %w", path, err)
+	}
+	return true, nil
+}
+
+func (b *fileBackend) Mkdir(_ context.Context, path string) error {
+	if err := os.MkdirAll(path, 0755); err != nil {
+		return fmt.Errorf("mkdir %s: %w", path, err)
+	}
+	return nil
+}
+
+func (b *fileBackend) FileExists(_ context.Context, path string) (bool, error) {
+	info, err := os.Stat(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil
+		}
+		return false, fmt.Errorf("stat %s: %w", path, err)
+	}
+	return !info.IsDir(), nil
+}

adk/middlewares/team/chat_model.go

@@ -0,0 +1,97 @@
+/*
+ * Copyright 2026 CloudWeGo Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/cloudwego/eino-ext/components/model/ark"
+	"github.com/cloudwego/eino-ext/components/model/openai"
+	arkmodel "github.com/volcengine/volcengine-go-sdk/service/arkruntime/model"
+
+	"github.com/cloudwego/eino/components/model"
+)
+
+func NewChatModel(ctx context.Context) (cm model.ToolCallingChatModel, err error) {
+	o := &option{}
+
+	if modelName := os.Getenv("ARK_MODEL"); modelName != "" {
+		conf := &ark.ChatModelConfig{
+			APIKey:      os.Getenv("ARK_API_KEY"),
+			BaseURL:     os.Getenv("ARK_BASE_URL"),
+			Region:      os.Getenv("ARK_REGION"),
+			Model:       modelName,
+			MaxTokens:   o.MaxTokens,
+			Temperature: o.Temperature,
+			TopP:        o.TopP,
+		}
+		if o.DisableThinking != nil && *o.DisableThinking {
+			conf.Thinking = &arkmodel.Thinking{
+				Type: arkmodel.ThinkingTypeDisabled,
+			}
+		}
+		if o.JsonSchema != nil {
+			conf.ResponseFormat = &ark.ResponseFormat{
+				Type: arkmodel.ResponseFormatJSONSchema,
+				JSONSchema: &arkmodel.ResponseFormatJSONSchemaJSONSchemaParam{
+					Name:        o.JsonSchema.Name,
+					Description: o.JsonSchema.Description,
+					Schema:      o.JsonSchema.JSONSchema,
+					Strict:      o.JsonSchema.Strict,
+				},
+			}
+		}
+		cm, err = ark.NewChatModel(ctx, conf)
+
+	} else if modelName = os.Getenv("OPENAI_MODEL"); modelName != "" {
+		conf := &openai.ChatModelConfig{
+			APIKey: os.Getenv("OPENAI_API_KEY"),
+			ByAzure: func() bool {
+				return os.Getenv("OPENAI_BY_AZURE") == "true"
+			}(),
+			BaseURL:     os.Getenv("OPENAI_BASE_URL"),
+			Model:       modelName,
+			MaxTokens:   o.MaxTokens,
+			Temperature: o.Temperature,
+		}
+		if o.JsonSchema != nil {
+			conf.ResponseFormat = &openai.ChatCompletionResponseFormat{
+				Type:       openai.ChatCompletionResponseFormatTypeJSONSchema,
+				JSONSchema: o.JsonSchema,
+			}
+		}
+		cm, err = openai.NewChatModel(ctx, conf)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if cm == nil {
+		return nil, fmt.Errorf("no model config")
+	}
+
+	return cm, nil
+}
+
+type option struct {
+	MaxTokens       *int
+	Temperature     *float32
+	TopP            *float32
+	DisableThinking *bool
+	JsonSchema      *openai.ChatCompletionResponseFormatJSONSchema
+}