address Danielle's comments

Author: johnstcn

cmd/attach/attach.go

@@ -129,40 +129,31 @@ func WriteRawInputOverHTTP(ctx context.Context, url string, msg string) error {
 	return nil
 }
 
-// statusResponse is used to parse the /status endpoint response.
-type statusResponse struct {
-	Status    string `json:"status"`
-	AgentType string `json:"agent_type"`
-	Backend   string `json:"backend"`
-}
-
-func checkACPMode(remoteUrl string) error {
-	resp, err := http.Get(remoteUrl + "/status")
+func checkACPMode(remoteURL string) (bool, error) {
+	resp, err := http.Get(remoteURL + "/status")
 	if err != nil {
-		return xerrors.Errorf("failed to check server status: %w", err)
+		return false, xerrors.Errorf("failed to check server status: %w", err)
 	}
 	defer func() { _ = resp.Body.Close() }()
 
 	if resp.StatusCode != http.StatusOK {
-		return xerrors.Errorf("unexpected %d response from server: %s", resp.StatusCode, resp.Status)
+		return false, xerrors.Errorf("unexpected %d response from server: %s", resp.StatusCode, resp.Status)
 	}
 
-	var status statusResponse
-	if err := json.NewDecoder(resp.Body).Decode(&status); err != nil {
-		return xerrors.Errorf("failed to decode server status: %w", err)
+	var status httpapi.StatusResponse
+	if err := json.NewDecoder(resp.Body).Decode(&status.Body); err != nil {
+		return false, xerrors.Errorf("failed to decode server status: %w", err)
 	}
 
-	if status.Backend == "acp" {
-		return xerrors.New("attach is not supported in ACP mode. The server is running with --experimental-acp which uses JSON-RPC instead of terminal emulation.")
-	}
-
-	return nil
+	return status.Body.Transport == httpapi.TransportACP, nil
 }
 
-func runAttach(remoteUrl string) error {
+func runAttach(remoteURL string) error {
 	// Check if server is running in ACP mode (attach not supported)
-	if err := checkACPMode(remoteUrl); err != nil {
-		return err
+	if isACP, err := checkACPMode(remoteURL); err != nil {
+		_, _ = fmt.Fprintf(os.Stderr, "WARN: Unable to check server: %s", err.Error())
+	} else if isACP {
+		return xerrors.New("attach is not yet supported in ACP mode")
 	}
 
 	ctx, cancel := context.WithCancel(context.Background())
@@ -187,7 +178,7 @@ func runAttach(remoteUrl string) error {
 	readScreenErrCh := make(chan error, 1)
 	go func() {
 		defer close(readScreenErrCh)
-		if err := ReadScreenOverHTTP(ctx, remoteUrl+"/internal/screen", screenCh); err != nil {
+		if err := ReadScreenOverHTTP(ctx, remoteURL+"/internal/screen", screenCh); err != nil {
 			if errors.Is(err, context.Canceled) {
 				return
 			}
@@ -210,7 +201,7 @@ func runAttach(remoteUrl string) error {
 				if input == "\x03" {
 					continue
 				}
-				if err := WriteRawInputOverHTTP(ctx, remoteUrl+"/message", input); err != nil {
+				if err := WriteRawInputOverHTTP(ctx, remoteURL+"/message", input); err != nil {
 					writeRawInputErrCh <- xerrors.Errorf("failed to write raw input: %w", err)
 					return
 				}

cmd/server/server.go

@@ -112,7 +112,7 @@ func runServer(ctx context.Context, logger *slog.Logger, argsToPass []string) er
 	}
 
 	var agentIO st.AgentIO
-	var transport = "pty"
+	transport := "pty"
 	var process *termexec.Process
 	var acpResult *httpapi.SetupACPResult
 
@@ -148,7 +148,7 @@ func runServer(ctx context.Context, logger *slog.Logger, argsToPass []string) er
 	srv, err := httpapi.NewServer(ctx, httpapi.ServerConfig{
 		AgentType:      agentType,
 		AgentIO:        agentIO,
-		Transport:      transport,
+		Transport:      httpapi.Transport(transport),
 		Port:           port,
 		ChatBasePath:   viper.GetString(FlagChatBasePath),
 		AllowedHosts:   viper.GetStringSlice(FlagAllowedHosts),

lib/httpapi/models.go

@@ -25,6 +25,22 @@ func (m MessageType) Schema(r huma.Registry) *huma.Schema {
 	return util.OpenAPISchema(r, "MessageType", MessageTypeValues)
 }
 
+type Transport string
+
+const (
+	TransportPTY Transport = "pty"
+	TransportACP Transport = "acp"
+)
+
+var TransportValues = []Transport{
+	TransportPTY,
+	TransportACP,
+}
+
+func (tr Transport) Schema(r huma.Registry) *huma.Schema {
+	return util.OpenAPISchema(r, "Transport", TransportValues)
+}
+
 // Message represents a message
 type Message struct {
 	Id      int                 `json:"id" doc:"Unique identifier for the message. This identifier also represents the order of the message in the conversation history."`
@@ -38,7 +54,7 @@ type StatusResponse struct {
 	Body struct {
 		Status    AgentStatus  `json:"status" doc:"Current agent status. 'running' means that the agent is processing a message, 'stable' means that the agent is idle and waiting for input."`
 		AgentType mf.AgentType `json:"agent_type" doc:"Type of the agent being used by the server."`
-		Backend   string       `json:"backend" doc:"Backend transport being used ('acp' or 'pty')."`
+		Transport Transport    `json:"transport" doc:"Backend transport being used ('acp' or 'pty')."`
 	}
 }
 

lib/httpapi/server.go

@@ -49,7 +49,7 @@ type Server struct {
 	chatBasePath string
 	tempDir      string
 	clock        quartz.Clock
-	transport    string
+	transport    Transport
 }
 
 func (s *Server) NormalizeSchema(schema any) any {
@@ -101,7 +101,7 @@ const snapshotInterval = 25 * time.Millisecond
 type ServerConfig struct {
 	AgentType      mf.AgentType
 	AgentIO        st.AgentIO
-	Transport      string
+	Transport      Transport
 	Port           int
 	ChatBasePath   string
 	AllowedHosts   []string
@@ -437,7 +437,7 @@ func (s *Server) getStatus(ctx context.Context, input *struct{}) (*StatusRespons
 	resp := &StatusResponse{}
 	resp.Body.Status = agentStatus
 	resp.Body.AgentType = s.agentType
-	resp.Body.Backend = s.transport
+	resp.Body.Transport = s.transport
 
 	return resp, nil
 }

lib/httpapi/setup.go

@@ -133,4 +133,3 @@ func SetupACP(ctx context.Context, config SetupACPConfig) (*SetupACPResult, erro
 		Done:    done,
 	}, nil
 }
-

openapi.json

@@ -269,22 +269,31 @@
             "description": "Type of the agent being used by the server.",
             "type": "string"
           },
-          "backend": {
-            "description": "Backend transport being used ('acp' or 'pty').",
-            "type": "string"
-          },
           "status": {
             "$ref": "#/components/schemas/AgentStatus",
             "description": "Current agent status. 'running' means that the agent is processing a message, 'stable' means that the agent is idle and waiting for input."
+          },
+          "transport": {
+            "$ref": "#/components/schemas/Transport",
+            "description": "Backend transport being used ('acp' or 'pty')."
           }
         },
         "required": [
           "agent_type",
-          "backend",
-          "status"
+          "status",
+          "transport"
         ],
         "type": "object"
       },
+      "Transport": {
+        "enum": [
+          "acp",
+          "pty"
+        ],
+        "example": "pty",
+        "title": "Transport",
+        "type": "string"
+      },
       "UploadResponseBody": {
         "additionalProperties": false,
         "properties": {