Add read file tool

go.mod

@@ -0,0 +1,20 @@
+module agent
+
+go 1.24.2
+
+require (
+	github.com/anthropics/anthropic-sdk-go v1.3.0
+	github.com/invopop/jsonschema v0.13.0
+)
+
+require (
+	github.com/bahlo/generic-list-go v0.2.0 // indirect
+	github.com/buger/jsonparser v1.1.1 // indirect
+	github.com/mailru/easyjson v0.7.7 // indirect
+	github.com/tidwall/gjson v1.14.4 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.1 // indirect
+	github.com/tidwall/sjson v1.2.5 // indirect
+	github.com/wk8/go-ordered-map/v2 v2.1.8 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

go.sum

@@ -0,0 +1,33 @@
+github.com/anthropics/anthropic-sdk-go v1.3.0 h1:KroW4oDT3KzFT71d3bnu4DxLFAEPvY+d1c6z2CrOz/s=
+github.com/anthropics/anthropic-sdk-go v1.3.0/go.mod h1:AapDW22irxK2PSumZiQXYUFvsdQgkwIWlpESweWZI/c=
+github.com/bahlo/generic-list-go v0.2.0 h1:5sz/EEAK+ls5wF+NeqDpk5+iNdMDXrh3z3nPnH1Wvgk=
+github.com/bahlo/generic-list-go v0.2.0/go.mod h1:2KvAjgMlE5NNynlg/5iLrrCCZ2+5xWbdbCW3pNTGyYg=
+github.com/buger/jsonparser v1.1.1 h1:2PnMjfWD7wBILjqQbt530v576A/cAbQvEW9gGIpYMUs=
+github.com/buger/jsonparser v1.1.1/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/invopop/jsonschema v0.13.0 h1:KvpoAJWEjR3uD9Kbm2HWJmqsEaHt8lBUpd0qHcIi21E=
+github.com/invopop/jsonschema v0.13.0/go.mod h1:ffZ5Km5SWWRAIN6wbDXItl95euhFz2uON45H2qjYt+0=
+github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
+github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
+github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/tidwall/gjson v1.14.2/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/gjson v1.14.4 h1:uo0p8EbA09J7RQaflQ1aBRffTR7xedD2bcIVSYxLnkM=
+github.com/tidwall/gjson v1.14.4/go.mod h1:/wbyibRr2FHMks5tjHJ5F8dMZh3AcwJEMf5vlfC0lxk=
+github.com/tidwall/match v1.1.1 h1:+Ho715JplO36QYgwN9PGYNhgZvoUSc9X2c80KVTi+GA=
+github.com/tidwall/match v1.1.1/go.mod h1:eRSPERbgtNPcGhD8UCthc6PmLEQXEWd3PRB5JTxsfmM=
+github.com/tidwall/pretty v1.2.0/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
+github.com/tidwall/pretty v1.2.1 h1:qjsOFOWWQl+N3RsoF5/ssm1pHmJJwhjlSbZ51I6wMl4=
+github.com/tidwall/pretty v1.2.1/go.mod h1:ITEVvHYasfjBbM0u2Pg8T2nJnzm8xPwvNhhsoaGGjNU=
+github.com/tidwall/sjson v1.2.5 h1:kLy8mja+1c9jlljvWTlSazM7cKDRfJuR/bOJhcY5NcY=
+github.com/tidwall/sjson v1.2.5/go.mod h1:Fvgq9kS/6ociJEDnK0Fk1cpYF4FIW6ZF7LAe+6jwd28=
+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=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

main.go

@@ -0,0 +1,181 @@
+package main
+
+import (
+	"bufio"
+	"context"
+	"encoding/json"
+	"fmt"
+	"os"
+
+	"github.com/anthropics/anthropic-sdk-go"
+	"github.com/invopop/jsonschema"
+)
+
+func main() {
+	client := anthropic.NewClient()
+
+	scanner := bufio.NewScanner(os.Stdin)
+	getUserMessage := func() (string, bool) {
+		if !scanner.Scan() {
+			return "", false
+		}
+		return scanner.Text(), true
+	}
+	tools := []ToolDefinition{ReadFileDefinition}
+
+	agent := NewAgent(&client, getUserMessage, tools)
+	err := agent.Run(context.TODO())
+	if err != nil {
+		fmt.Printf("Error: %s\n", err.Error())
+	}
+}
+
+func NewAgent(client *anthropic.Client, getUserMessage func() (string, bool), tools []ToolDefinition) *Agent {
+	return &Agent{
+		client:         client,
+		getUserMessage: getUserMessage,
+		tools:          tools,
+	}
+}
+
+type Agent struct {
+	client         *anthropic.Client
+	getUserMessage func() (string, bool)
+	tools          []ToolDefinition
+}
+
+func (a *Agent) Run(ctx context.Context) error {
+	conversation := []anthropic.MessageParam{}
+
+	fmt.Println("Chat with Claude (use 'ctrl-c' to quit)")
+
+	readUserInput := true
+	for {
+		if readUserInput {
+			fmt.Print("\u001b[94mYou\u001b[0m: ")
+			userInput, ok := a.getUserMessage()
+			if !ok {
+				break
+			}
+
+			userMessage := anthropic.NewUserMessage(anthropic.NewTextBlock(userInput))
+			conversation = append(conversation, userMessage)
+		}
+
+		message, err := a.runInference(ctx, conversation)
+		if err != nil {
+			return err
+		}
+		conversation = append(conversation, message.ToParam())
+
+		toolResults := []anthropic.ContentBlockParamUnion{}
+		for _, content := range message.Content {
+			switch content.Type {
+			case "text":
+				fmt.Printf("\u001b[93mClaude\u001b[0m: %s\n", content.Text)
+			case "tool_use":
+				result := a.executeTool(content.ID, content.Name, content.Input)
+				toolResults = append(toolResults, result)
+			}
+		}
+		if len(toolResults) == 0 {
+			readUserInput = true
+			continue
+		}
+		readUserInput = false
+		conversation = append(conversation, anthropic.NewUserMessage(toolResults...))
+	}
+
+	return nil
+}
+
+func (a *Agent) executeTool(id, name string, input json.RawMessage) anthropic.ContentBlockParamUnion {
+	var toolDef ToolDefinition
+	var found bool
+	for _, tool := range a.tools {
+		if tool.Name == name {
+			toolDef = tool
+			found = true
+			break
+		}
+	}
+	if !found {
+		return anthropic.NewToolResultBlock(id, "tool not found", true)
+	}
+
+	fmt.Printf("\u001b[92mtool\u001b[0m: %s(%s)\n", name, input)
+	response, err := toolDef.Function(input)
+	if err != nil {
+		return anthropic.NewToolResultBlock(id, err.Error(), true)
+	}
+	return anthropic.NewToolResultBlock(id, response, false)
+}
+
+func (a *Agent) runInference(ctx context.Context, conversation []anthropic.MessageParam) (*anthropic.Message, error) {
+	anthropicTools := []anthropic.ToolUnionParam{}
+	for _, tool := range a.tools {
+		anthropicTools = append(anthropicTools, anthropic.ToolUnionParam{
+			OfTool: &anthropic.ToolParam{
+				Name:        tool.Name,
+				Description: anthropic.String(tool.Description),
+				InputSchema: tool.InputSchema,
+			},
+		})
+	}
+
+	message, err := a.client.Messages.New(ctx, anthropic.MessageNewParams{
+		Model:     anthropic.ModelClaude3_7SonnetLatest,
+		MaxTokens: int64(1024),
+		Messages:  conversation,
+		Tools:     anthropicTools,
+	})
+	return message, err
+}
+
+type ToolDefinition struct {
+	Name        string                         `json:"name"`
+	Description string                         `json:"description"`
+	InputSchema anthropic.ToolInputSchemaParam `json:"input_schema"`
+	Function    func(input json.RawMessage) (string, error)
+}
+
+var ReadFileDefinition = ToolDefinition{
+	Name:        "read_file",
+	Description: "Read the contents of a given relative file path. Use this when you want to see what's inside a file. Do not use this with directory names.",
+	InputSchema: ReadFileInputSchema,
+	Function:    ReadFile,
+}
+
+type ReadFileInput struct {
+	Path string `json:"path" jsonschema_description:"The relative path of a file in the working directory."`
+}
+
+var ReadFileInputSchema = GenerateSchema[ReadFileInput]()
+
+func ReadFile(input json.RawMessage) (string, error) {
+	readFileInput := ReadFileInput{}
+	err := json.Unmarshal(input, &readFileInput)
+	if err != nil {
+		panic(err)
+	}
+
+	content, err := os.ReadFile(readFileInput.Path)
+	if err != nil {
+		return "", err
+	}
+	return string(content), nil
+}
+
+func GenerateSchema[T any]() anthropic.ToolInputSchemaParam {
+	reflector := jsonschema.Reflector{
+		AllowAdditionalProperties: false,
+		DoNotReference:            true,
+	}
+	var v T
+
+	schema := reflector.Reflect(v)
+
+	return anthropic.ToolInputSchemaParam{
+		Properties: schema.Properties,
+	}
+}