format

agents/const.go

@@ -0,0 +1,3 @@
+package agents
+
+var agentScratchpad = "agent_scratchpad"

agents/errors.go

@@ -20,6 +20,8 @@ var (
 	// ErrInvalidChainReturnType is returned if the internal chain of the agent returns a value in the
 	// "text" filed that is not a string.
 	ErrInvalidChainReturnType = errors.New("agent chain did not return a string")
+	// ErrInvalidLLMGenerationsMessageReturn is returned if the internal llm of the agent returns a value generations message is nil.
+	ErrInvalidLLMGenerationsMessageReturn = errors.New("agent llm did not return valid generations message")
 )
 
 // ParserErrorHandler is the struct used to handle parse errors from the agent in the executor. If

agents/executor_test.go

@@ -2,7 +2,6 @@ package agents_test
 
 import (
 	"context"
-	"github.com/tmc/langchaingo/prompts"
 	"os"
 	"strings"
 	"testing"
@@ -11,6 +10,7 @@ import (
 	"github.com/tmc/langchaingo/agents"
 	"github.com/tmc/langchaingo/chains"
 	"github.com/tmc/langchaingo/llms/openai"
+	"github.com/tmc/langchaingo/prompts"
 	"github.com/tmc/langchaingo/schema"
 	"github.com/tmc/langchaingo/tools"
 	"github.com/tmc/langchaingo/tools/serpapi"
@@ -124,12 +124,15 @@ func TestExecutorWithOpenAIFunctionAgent(t *testing.T) {
 		[]tools.Tool{searchTool, calculator},
 		agents.OpenAIFunctionAgentDescription,
 		agents.OpenAIOption.WithSystemMessage("you are a helpful assistant"),
-		agents.OpenAIOption.WithExtraMessages([]prompts.MessageFormatter{prompts.NewHumanMessagePromptTemplate("please be strict", nil)}),
+		agents.OpenAIOption.WithExtraMessages([]prompts.MessageFormatter{
+			prompts.NewHumanMessagePromptTemplate("please be strict", nil),
+		}),
 	)
 	require.NoError(t, err)
 
 	result, err := chains.Run(context.Background(), a, "what is HK singer Eason Chan's years old?") //nolint:lll
 	require.NoError(t, err)
 
-	require.True(t, strings.Contains(result, "47") || strings.Contains(result, "49"), "correct answer 47 or 49 not in response")
+	require.True(t, strings.Contains(result, "47") || strings.Contains(result, "49"),
+		"correct answer 47 or 49 not in response")
 }

agents/openai_functions_agent.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+
 	"github.com/tmc/langchaingo/callbacks"
 	"github.com/tmc/langchaingo/llms"
 	"github.com/tmc/langchaingo/prompts"
@@ -84,7 +85,7 @@ func (o *OpenAIFunctionsAgent) Plan(
 	for key, value := range inputs {
 		fullInputs[key] = value
 	}
-	fullInputs["agent_scratchpad"] = o.constructScratchPad(intermediateSteps)
+	fullInputs[agentScratchpad] = o.constructScratchPad(intermediateSteps)
 
 	var stream func(ctx context.Context, chunk []byte) error
 
@@ -106,7 +107,6 @@ func (o *OpenAIFunctionsAgent) Plan(
 		llms.WithFunctions(o.functions()),
 		llms.WithStreamingFunc(stream),
 	)
-
 	if err != nil {
 		return nil, nil, err
 	}
@@ -120,7 +120,7 @@ func (o *OpenAIFunctionsAgent) GetInputKeys() []string {
 	// Remove inputs given in plan.
 	agentInput := make([]string, 0, len(chainInputs))
 	for _, v := range chainInputs {
-		if v == "agent_scratchpad" {
+		if v == agentScratchpad {
 			continue
 		}
 		agentInput = append(agentInput, v)
@@ -138,7 +138,7 @@ func createOpenAIFunctionPrompt(opts CreationOptions) prompts.ChatPromptTemplate
 	messageFormatters = append(messageFormatters, opts.extraMessages...)
 	messageFormatters = append(messageFormatters, prompts.NewHumanMessagePromptTemplate("{{.input}}", []string{"input"}))
 	messageFormatters = append(messageFormatters, prompts.MessagesPlaceholder{
-		VariableName: "agent_scratchpad",
+		VariableName: agentScratchpad,
 	})
 
 	tmpl := prompts.NewChatPromptTemplate(messageFormatters)
@@ -146,26 +146,26 @@ func createOpenAIFunctionPrompt(opts CreationOptions) prompts.ChatPromptTemplate
 }
 
 func (o *OpenAIFunctionsAgent) constructScratchPad(steps []schema.AgentStep) []schema.ChatMessage {
-	if len(steps) <= 0 {
+	if len(steps) == 0 {
 		return nil
 	}
 
 	var messages []schema.ChatMessage
-	if len(steps) > 0 {
-		for _, step := range steps {
-			messages = append(messages, schema.FunctionChatMessage{
-				Name:    step.Action.Tool,
-				Content: step.Observation,
-			})
-		}
+	for _, step := range steps {
+		messages = append(messages, schema.FunctionChatMessage{
+			Name:    step.Action.Tool,
+			Content: step.Observation,
+		})
 	}
 
 	return messages
 }
 
-func (o *OpenAIFunctionsAgent) ParseOutput(llmResult llms.LLMResult) ([]schema.AgentAction, *schema.AgentFinish, error) {
+func (o *OpenAIFunctionsAgent) ParseOutput(llmResult llms.LLMResult) (
+	[]schema.AgentAction, *schema.AgentFinish, error) {
 	if llmResult.Generations[0][0] == nil || llmResult.Generations[0][0].Message == nil {
-		return nil, nil, fmt.Errorf("wrong llmResult from OpenAIFunctionsAgent")
+		return nil, nil, fmt.Errorf("%w: %s", ErrInvalidLLMGenerationsMessageReturn,
+			"wrong llmResult from OpenAIFunctionsAgent")
 	}
 
 	// finish
@@ -188,11 +188,12 @@ func (o *OpenAIFunctionsAgent) ParseOutput(llmResult llms.LLMResult) ([]schema.A
 		return nil, nil, err
 	}
 
-	var toolInput string
+	toolInput := toolInputStr
 	if arg1, ok := toolInputMap["__arg1"]; ok {
-		toolInput = arg1.(string)
-	} else {
-		toolInput = toolInputStr
+		toolInputCheck, ok := arg1.(string)
+		if ok {
+			toolInput = toolInputCheck
+		}
 	}
 
 	contentMsg := "\n"

prompts/message_prompt_template.go

@@ -2,6 +2,7 @@ package prompts
 
 import (
 	"fmt"
+
 	"github.com/tmc/langchaingo/schema"
 )
 
@@ -111,7 +112,7 @@ type MessagesPlaceholder struct {
 	VariableName string
 }
 
-// FormatMessages formats the messages from the values by variable name
+// FormatMessages formats the messages from the values by variable name.
 func (p MessagesPlaceholder) FormatMessages(values map[string]any) ([]schema.ChatMessage, error) {
 	value, ok := values[p.VariableName]
 	if !ok {