fix(adk): disable automatic instruction rendering in DeepAgent (#726)

Author: hi-pender

adk/prebuilt/deep/deep.go

@@ -114,11 +114,24 @@ func New(ctx context.Context, cfg *Config) (adk.ResumableAgent, error) {
 		MaxIterations: cfg.MaxIteration,
 		Middlewares:   append(middlewares, cfg.Middlewares...),
 
+		GenModelInput:    genModelInput,
 		ModelRetryConfig: cfg.ModelRetryConfig,
 		OutputKey:        cfg.OutputKey,
 	})
 }
 
+func genModelInput(ctx context.Context, instruction string, input *adk.AgentInput) ([]*schema.Message, error) {
+	msgs := make([]*schema.Message, 0, len(input.Messages)+1)
+
+	if instruction != "" {
+		msgs = append(msgs, schema.SystemMessage(instruction))
+	}
+
+	msgs = append(msgs, input.Messages...)
+
+	return msgs, nil
+}
+
 func buildBuiltinAgentMiddlewares(withoutWriteTodos bool) ([]adk.AgentMiddleware, error) {
 	var ms []adk.AgentMiddleware
 	if !withoutWriteTodos {

adk/prebuilt/deep/deep_test.go

@@ -32,6 +32,40 @@ import (
 	"github.com/cloudwego/eino/schema"
 )
 
+func TestGenModelInput(t *testing.T) {
+	ctx := context.Background()
+
+	t.Run("WithInstruction", func(t *testing.T) {
+		input := &adk.AgentInput{
+			Messages: []*schema.Message{
+				schema.UserMessage("hello"),
+			},
+		}
+
+		msgs, err := genModelInput(ctx, "You are a helpful assistant", input)
+		assert.NoError(t, err)
+		assert.Len(t, msgs, 2)
+		assert.Equal(t, schema.System, msgs[0].Role)
+		assert.Equal(t, "You are a helpful assistant", msgs[0].Content)
+		assert.Equal(t, schema.User, msgs[1].Role)
+		assert.Equal(t, "hello", msgs[1].Content)
+	})
+
+	t.Run("WithoutInstruction", func(t *testing.T) {
+		input := &adk.AgentInput{
+			Messages: []*schema.Message{
+				schema.UserMessage("hello"),
+			},
+		}
+
+		msgs, err := genModelInput(ctx, "", input)
+		assert.NoError(t, err)
+		assert.Len(t, msgs, 1)
+		assert.Equal(t, schema.User, msgs[0].Role)
+		assert.Equal(t, "hello", msgs[0].Content)
+	})
+}
+
 func TestWriteTodos(t *testing.T) {
 	m, err := buildBuiltinAgentMiddlewares(false)
 	assert.NoError(t, err)