feat(adk): definition for agent_middleware

.gitignore

@@ -35,6 +35,8 @@ output/*
 # Vscode files
 .vscode
 
+/CLAUDE.md
+
 /patches
 
 /vendor

adk/agent_middleware.go

@@ -0,0 +1,71 @@
+package adk
+
+import (
+	"context"
+
+	"github.com/cloudwego/eino/components/tool"
+	"github.com/cloudwego/eino/schema"
+)
+
+type AgentState struct {
+	SystemPrompt string
+	// Messages are the messages to be sent to the model.
+	// excluding system prompt
+	Messages []Message
+	Tools    []tool.BaseTool
+	Choice   *schema.ToolChoice
+
+	Extra map[string]any
+}
+
+type ToolRequest struct {
+	State    *AgentState
+	ToolCall schema.ToolCall
+}
+
+type BeforeModel func(ctx context.Context, origin *AgentState) (changed *AgentState, err error)
+type AfterModel func(ctx context.Context, resp *AgentState) (changed *AgentState, err error)
+type ModelHandler func(ctx context.Context, req *AgentState) (msg Message, err error)
+type ModelMW func(ctx context.Context, req *AgentState, next ModelHandler) (msg Message, err error)
+
+type ToolHandler func(ctx context.Context, req *ToolRequest) (result string, err error)
+
+type ToolMW func(ctx context.Context, req *ToolRequest, next ToolHandler) (result string, err error)
+
+type AgentMiddleware interface {
+	MiddlewareName() string
+}
+
+type AgentMiddlewareBeforeModel interface {
+	AgentMiddleware
+	BeforeModel
+}
+
+type AgentMiddlewareAfterModel interface {
+	AgentMiddleware
+	AfterModel
+}
+
+type AgentMiddlewareModelMW interface {
+	AgentMiddleware
+	ModelMW
+}
+
+type AgentMiddlewareToolMW interface {
+	AgentMiddleware
+	ToolMW
+}
+
+type AgentMiddleware1 interface {
+	BeforeModel
+	AfterModel
+	ModelMW
+	ToolMW
+}
+
+type AgentMiddleware2 struct {
+	BeforeModel      BeforeModel
+	AfterModel       AfterModel
+	WrapModelHandler ModelMW
+	WrapToolHandler  ToolMW
+}