Merge pull request #40 from ayakut16/fix/show-logs

Add --server-logs flag

Author: f

README.md

@@ -166,15 +166,16 @@ mcp tools npx -y @modelcontextprotocol/server-filesystem ~
 The default format now displays tools in a colorized man-page style:
 
 ```
-read_file(path:str, [limit:int], [offset:int])
-     Reads a file from the filesystem
-
+read_file(path:str)
+     Read the complete contents of a file from the file system.
+read_multiple_files(paths:str[])
+     Read the contents of multiple files simultaneously.
 list_dir(path:str)
-     Lists directory contents
-
+     Lists the contents of a directory.
+write_file(path:str, content:str)
+     Writes content to a file.
 grep_search(pattern:str, [excludePatterns:str[]])
-     Search files with pattern
-
+     Search files with pattern.
 edit_file(edits:{newText:str,oldText:str}[], path:str)
      Edit a file with multiple text replacements
 ```
@@ -236,7 +237,7 @@ mcp call read_file --params '{"path":"/path/to/file"}' npx -y @modelcontextproto
 mcp call resource:test://static/resource/1 npx -y @modelcontextprotocol/server-everything -f json | jq ".contents[0].text"
 ```
 
-or 
+or
 
 ```bash
 mcp read-resource test://static/resource/1 npx -y @modelcontextprotocol/server-everything -f json | jq ".contents[0].text"
@@ -248,6 +249,28 @@ mcp read-resource test://static/resource/1 npx -y @modelcontextprotocol/server-e
 mcp get-prompt simple_prompt npx -y @modelcontextprotocol/server-everything -f json | jq ".messages[0].content.text"
 ```
 
+#### Viewing Server Logs
+
+When using client commands that make calls to the server, you can add the `--server-logs` flag to see the server logs related to your request:
+
+```bash
+# View server logs when listing tools
+mcp tools --server-logs npx -y @modelcontextprotocol/server-filesystem ~
+```
+
+Output:
+```
+[>] Secure MCP Filesystem Server running on stdio
+[>] Allowed directories: [ '/Users/fka/' ]
+read_file(path:str)
+     Read the complete contents of a file from the file system.
+read_multiple_files(paths:str[])
+     Read the contents of multiple files simultaneously.
+... and the other tools available on this server
+```
+
+This can be helpful for debugging or understanding what's happening on the server side when executing these commands.
+
 ### Interactive Shell
 
 The interactive shell mode allows you to run multiple MCP commands in a single session:
@@ -330,7 +353,7 @@ After scaffolding, you can build and run your MCP server:
 npm install
 
 # Build the TypeScript code
-npm run build 
+npm run build
 
 # Test the server with MCP Tools
 mcp tools node build/index.js

cmd/mcptools/commands/get_prompt.go

@@ -45,6 +45,9 @@ func GetPromptCmd() *cobra.Command {
 				case (cmdArgs[i] == FlagParams || cmdArgs[i] == FlagParamsShort) && i+1 < len(cmdArgs):
 					ParamsString = cmdArgs[i+1]
 					i += 2
+				case cmdArgs[i] == FlagServerLogs:
+					ShowServerLogs = true
+					i++
 				case !promptExtracted:
 					promptName = cmdArgs[i]
 					promptExtracted = true

cmd/mcptools/commands/read_resource.go

@@ -24,7 +24,7 @@ func ReadResourceCmd() *cobra.Command {
 				fmt.Fprintln(os.Stderr, "Error: resource name is required")
 				fmt.Fprintln(
 					os.Stderr,
-					"Example: mcp read-resource npx -y @modelcontextprotocol/server-filesystem ~",
+					"Example: mcp read-resource test://static/resource/1 npx -y @modelcontextprotocol/server-filesystem ~",
 				)
 				os.Exit(1)
 			}
@@ -58,7 +58,7 @@ func ReadResourceCmd() *cobra.Command {
 				fmt.Fprintln(os.Stderr, "Error: resource name is required")
 				fmt.Fprintln(
 					os.Stderr,
-					"Example: mcp read-resource npx -y @modelcontextprotocol/server-filesystem ~",
+					"Example: mcp read-resource test://static/resource/1 npx -y @modelcontextprotocol/server-filesystem ~",
 				)
 				os.Exit(1)
 			}

cmd/mcptools/commands/root.go

@@ -15,6 +15,7 @@ const (
 	FlagParamsShort = "-p"
 	FlagHelp        = "--help"
 	FlagHelpShort   = "-h"
+	FlagServerLogs  = "--server-logs"
 )
 
 // entity types.
@@ -31,6 +32,8 @@ var (
 	FormatOption = "table"
 	// ParamsString is the params for the command.
 	ParamsString string
+	// ShowServerLogs is a flag to show server logs.
+	ShowServerLogs bool
 )
 
 // RootCmd creates the root command.

cmd/mcptools/commands/shell.go

@@ -30,10 +30,14 @@ func ShellCmd() *cobra.Command { //nolint:gocyclo
 			parsedArgs := []string{}
 
 			for i := 0; i < len(cmdArgs); i++ {
-				if (cmdArgs[i] == FlagFormat || cmdArgs[i] == FlagFormatShort) && i+1 < len(cmdArgs) {
+				switch {
+				case (cmdArgs[i] == FlagFormat || cmdArgs[i] == FlagFormatShort) && i+1 < len(cmdArgs):
 					FormatOption = cmdArgs[i+1]
 					i++
-				} else {
+				case cmdArgs[i] == FlagServerLogs:
+					ShowServerLogs = true
+					i++
+				default:
 					parsedArgs = append(parsedArgs, cmdArgs[i])
 				}
 			}

cmd/mcptools/commands/utils.go

@@ -27,6 +27,8 @@ var CreateClientFunc = func(args []string, opts ...client.Option) (*client.Clien
 		return nil, ErrCommandRequired
 	}
 
+	opts = append(opts, client.SetShowServerLogs(ShowServerLogs))
+
 	// Check if the first argument is an alias
 	if len(args) == 1 {
 		server, found := alias.GetServerCommand(args[0])
@@ -64,6 +66,9 @@ func ProcessFlags(args []string) []string {
 		case (args[i] == FlagFormat || args[i] == FlagFormatShort) && i+1 < len(args):
 			FormatOption = args[i+1]
 			i += 2
+		case args[i] == FlagServerLogs:
+			ShowServerLogs = true
+			i++
 		default:
 			parsedArgs = append(parsedArgs, args[i])
 			i++

cmd/mcptools/commands/utils_test.go

@@ -21,42 +21,56 @@ func TestProcessFlags(t *testing.T) {
 		args       []string
 		wantArgs   []string
 		wantFormat string
+		showLogs   bool
 	}{
 		{
 			name:       "no flags",
 			args:       []string{"cmd", "arg1", "arg2"},
 			wantArgs:   []string{"cmd", "arg1", "arg2"},
 			wantFormat: "",
+			showLogs:   false,
 		},
 		{
 			name:       "with long format flag",
 			args:       []string{"cmd", "--format", "json", "arg1"},
 			wantArgs:   []string{"cmd", "arg1"},
 			wantFormat: "json",
+			showLogs:   false,
 		},
 		{
 			name:       "with short format flag",
 			args:       []string{"cmd", "-f", "pretty", "arg1"},
 			wantArgs:   []string{"cmd", "arg1"},
 			wantFormat: "pretty",
+			showLogs:   false,
 		},
 		{
 			name:       "with format flag at end",
 			args:       []string{"cmd", "arg1", "--format", "table"},
 			wantArgs:   []string{"cmd", "arg1"},
 			wantFormat: "table",
+			showLogs:   false,
 		},
 		{
 			name:       "with invalid format option",
 			args:       []string{"cmd", "--format", "invalid", "arg1"},
 			wantArgs:   []string{"cmd", "arg1"},
 			wantFormat: "invalid",
+			showLogs:   false,
 		},
 		{
 			name:       "with format flag without value",
 			args:       []string{"cmd", "--format", "json"},
 			wantArgs:   []string{"cmd"},
 			wantFormat: "json",
+			showLogs:   false,
+		},
+		{
+			name:       "with server logs flag",
+			args:       []string{"cmd", "--server-logs", "arg1"},
+			wantArgs:   []string{"cmd", "arg1"},
+			wantFormat: "",
+			showLogs:   true,
 		},
 	}
 

pkg/client/client.go

@@ -33,6 +33,16 @@ func CloseTransportAfterExecute(closeTransport bool) Option {
 	}
 }
 
+// SetShowServerLogs sets whether to show server logs.
+func SetShowServerLogs(showLogs bool) Option {
+	return func(c *Client) {
+		t, ok := c.transport.(interface{ SetShowServerLogs(bool) })
+		if ok {
+			t.SetShowServerLogs(showLogs)
+		}
+	}
+}
+
 // NewWithTransport creates a new MCP client using the provided transport.
 // This allows callers to provide a custom transport implementation.
 func NewWithTransport(t transport.Transport) *Client {

pkg/transport/stdio.go

@@ -8,16 +8,18 @@ import (
 	"io"
 	"os"
 	"os/exec"
+	"strings"
 	"time"
 )
 
 // Stdio implements the Transport interface by executing a command
 // and communicating with it via stdin/stdout using JSON-RPC.
 type Stdio struct {
-	process *stdioProcess
-	command []string
-	nextID  int
-	debug   bool
+	process        *stdioProcess
+	command        []string
+	nextID         int
+	debug          bool
+	showServerLogs bool
 }
 
 // stdioProcess reflects the state of a running command.
@@ -50,6 +52,11 @@ func (t *Stdio) SetCloseAfterExecute(v bool) {
 	}
 }
 
+// SetShowServerLogs toggles whether to print server logs.
+func (t *Stdio) SetShowServerLogs(v bool) {
+	t.showServerLogs = v
+}
+
 // Execute implements the Transport interface by spawning a subprocess
 // and communicating with it via JSON-RPC over stdin/stdout.
 func (t *Stdio) Execute(method string, params any) (map[string]any, error) {
@@ -72,14 +79,13 @@ func (t *Stdio) Execute(method string, params any) (map[string]any, error) {
 
 	if !process.isInitializeSent {
 		if initErr := t.initialize(process.stdin, process.stdout); initErr != nil {
+			t.printStderr(process)
 			if t.debug {
 				fmt.Fprintf(os.Stderr, "DEBUG: Initialization failed: %v\n", initErr)
-				if process.stderrBuf.Len() > 0 {
-					fmt.Fprintf(os.Stderr, "DEBUG: stderr during init: %s\n", process.stderrBuf.String())
-				}
 			}
 			return nil, initErr
 		}
+		t.printStderr(process)
 		process.isInitializeSent = true
 	}
 
@@ -100,10 +106,10 @@ func (t *Stdio) Execute(method string, params any) (map[string]any, error) {
 	}
 
 	response, err := t.readResponse(process.stdout)
+	t.printStderr(process)
 	if err != nil {
 		return nil, err
 	}
-
 	err = t.closeProcess(process)
 	if err != nil {
 		return nil, err
@@ -112,6 +118,22 @@ func (t *Stdio) Execute(method string, params any) (map[string]any, error) {
 	return response.Result, nil
 }
 
+// printStderr prints and clears any accumulated stderr output.
+func (t *Stdio) printStderr(process *stdioProcess) {
+	if !t.showServerLogs {
+		return
+	}
+	if process.stderrBuf.Len() > 0 {
+		for _, line := range strings.SplitAfter(process.stderrBuf.String(), "\n") {
+			line = strings.TrimSuffix(line, "\n")
+			if line != "" {
+				fmt.Fprintf(os.Stderr, "[>] %s\n", line)
+			}
+		}
+		process.stderrBuf.Reset() // Clear the buffer after reading
+	}
+}
+
 // closeProcess waits for the command to finish, returning any error.
 func (t *Stdio) closeProcess(process *stdioProcess) error {
 	if t.process != nil {
@@ -130,13 +152,10 @@ func (t *Stdio) closeProcess(process *stdioProcess) error {
 	case waitErr := <-done:
 		if t.debug {
 			fmt.Fprintf(os.Stderr, "DEBUG: Command completed with err: %v\n", waitErr)
-			if process.stderrBuf.Len() > 0 {
-				fmt.Fprintf(os.Stderr, "DEBUG: stderr output:\n%s\n", process.stderrBuf.String())
-			}
 		}
 
 		if waitErr != nil && process.stderrBuf.Len() > 0 {
-			return fmt.Errorf("command error: %w, stderr: %s", waitErr, process.stderrBuf.String())
+			return fmt.Errorf("command error: %w", waitErr)
 		}
 	case <-time.After(1 * time.Second):
 		if t.debug {