feat: add amcs-cli — MCP tool CLI and stdio bridge

- cmd/amcs-cli: new CLI tool for human/AI MCP tool access
- amcs-cli tools: list all tools from remote MCP server
- amcs-cli call <tool> --arg k=v: invoke a tool, print JSON/YAML result
- amcs-cli stdio: stdio→HTTP MCP bridge for AI clients
- Config: ~/.config/amcs/config.yaml, AMCS_URL/AMCS_TOKEN env vars, --server/--token flags
- Token never logged in errors
- Makefile: add build-cli target

Closes #18

cmd/amcs-cli/cmd/call.go

@@ -0,0 +1,98 @@
+package cmd
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
+)
+
+var argFlags []string
+
+var callCmd = &cobra.Command{
+	Use:   "call <tool>",
+	Short: "Call a remote AMCS tool",
+	Args:  cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		toolName := args[0]
+		toolArgs, err := parseArgs(argFlags)
+		if err != nil {
+			return err
+		}
+
+		session, err := connectRemote(cmd.Context())
+		if err != nil {
+			return err
+		}
+		defer func() { _ = session.Close() }()
+
+		res, err := session.CallTool(cmd.Context(), &mcp.CallToolParams{Name: toolName, Arguments: toolArgs})
+		if err != nil {
+			return fmt.Errorf("call tool %q: %w", toolName, err)
+		}
+		return printOutput(res)
+	},
+}
+
+func init() {
+	callCmd.Flags().StringArrayVar(&argFlags, "arg", nil, "Tool argument in key=value format (repeatable)")
+	rootCmd.AddCommand(callCmd)
+}
+
+func parseArgs(items []string) (map[string]any, error) {
+	result := make(map[string]any, len(items))
+	for _, item := range items {
+		key, value, ok := strings.Cut(item, "=")
+		if !ok || strings.TrimSpace(key) == "" {
+			return nil, fmt.Errorf("invalid --arg %q: want key=value", item)
+		}
+		result[key] = parseScalar(value)
+	}
+	return result, nil
+}
+
+func parseScalar(s string) any {
+	if s == "true" || s == "false" {
+		b, _ := strconv.ParseBool(s)
+		return b
+	}
+	if i, err := strconv.ParseInt(s, 10, 64); err == nil {
+		return i
+	}
+	if f, err := strconv.ParseFloat(s, 64); err == nil && strings.ContainsAny(s, ".eE") {
+		return f
+	}
+	var v any
+	if err := json.Unmarshal([]byte(s), &v); err == nil {
+		switch v.(type) {
+		case map[string]any, []any, float64, bool, nil:
+			return v
+		}
+	}
+	return s
+}
+
+func printOutput(v any) error {
+	switch outputFlag {
+	case "yaml":
+		data, err := yaml.Marshal(v)
+		if err != nil {
+			return fmt.Errorf("marshal yaml: %w", err)
+		}
+		_, err = os.Stdout.Write(data)
+		return err
+	default:
+		data, err := json.MarshalIndent(v, "", "  ")
+		if err != nil {
+			return fmt.Errorf("marshal json: %w", err)
+		}
+		data = append(data, '\n')
+		_, err = os.Stdout.Write(data)
+		return err
+	}
+}

cmd/amcs-cli/cmd/config.go

@@ -0,0 +1,60 @@
+package cmd
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gopkg.in/yaml.v3"
+)
+
+type Config struct {
+	Server string `yaml:"server"`
+	Token  string `yaml:"token"`
+}
+
+func defaultConfigPath() (string, error) {
+	home, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("resolve home dir: %w", err)
+	}
+	return filepath.Join(home, ".config", "amcs", "config.yaml"), nil
+}
+
+func resolveConfigPath(path string) (string, error) {
+	if strings.TrimSpace(path) != "" {
+		return path, nil
+	}
+	return defaultConfigPath()
+}
+
+func loadConfigFile(path string) (Config, error) {
+	var cfg Config
+	data, err := os.ReadFile(path)
+	if err != nil {
+		if errors.Is(err, os.ErrNotExist) {
+			return cfg, nil
+		}
+		return cfg, fmt.Errorf("read config: %w", err)
+	}
+	if err := yaml.Unmarshal(data, &cfg); err != nil {
+		return cfg, fmt.Errorf("parse config: %w", err)
+	}
+	return cfg, nil
+}
+
+func saveConfigFile(path string, cfg Config) error {
+	if err := os.MkdirAll(filepath.Dir(path), 0o700); err != nil {
+		return fmt.Errorf("create config dir: %w", err)
+	}
+	data, err := yaml.Marshal(cfg)
+	if err != nil {
+		return fmt.Errorf("marshal config: %w", err)
+	}
+	if err := os.WriteFile(path, data, 0o600); err != nil {
+		return fmt.Errorf("write config: %w", err)
+	}
+	return nil
+}

cmd/amcs-cli/cmd/root.go

@@ -0,0 +1,134 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/spf13/cobra"
+)
+
+var (
+	cfgFile    string
+	serverFlag string
+	tokenFlag  string
+	outputFlag string
+	cfg        Config
+)
+
+var rootCmd = &cobra.Command{
+	Use:           "amcs-cli",
+	Short:         "CLI for connecting to a remote AMCS MCP server",
+	SilenceUsage:  true,
+	SilenceErrors: true,
+	PersistentPreRunE: func(cmd *cobra.Command, _ []string) error {
+		return loadConfig()
+	},
+}
+
+func Execute() {
+	if err := rootCmd.Execute(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func init() {
+	rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "Path to config file")
+	rootCmd.PersistentFlags().StringVar(&serverFlag, "server", "", "AMCS server URL")
+	rootCmd.PersistentFlags().StringVar(&tokenFlag, "token", "", "AMCS bearer token")
+	rootCmd.PersistentFlags().StringVar(&outputFlag, "output", "json", "Output format: json or yaml")
+}
+
+func loadConfig() error {
+	path, err := resolveConfigPath(cfgFile)
+	if err != nil {
+		return err
+	}
+	loaded, err := loadConfigFile(path)
+	if err != nil {
+		return err
+	}
+	cfg = loaded
+	if v := strings.TrimSpace(os.Getenv("AMCS_URL")); v != "" {
+		cfg.Server = v
+	}
+	if v := strings.TrimSpace(os.Getenv("AMCS_TOKEN")); v != "" {
+		cfg.Token = v
+	}
+	if v := strings.TrimSpace(serverFlag); v != "" {
+		cfg.Server = v
+	}
+	if v := strings.TrimSpace(tokenFlag); v != "" {
+		cfg.Token = v
+	}
+	outputFlag = strings.ToLower(strings.TrimSpace(outputFlag))
+	if outputFlag != "json" && outputFlag != "yaml" {
+		return fmt.Errorf("invalid --output %q: must be json or yaml", outputFlag)
+	}
+	return nil
+}
+
+func requireServer() error {
+	if strings.TrimSpace(cfg.Server) == "" {
+		return fmt.Errorf("server URL is required; set --server, AMCS_URL, or config server")
+	}
+	return nil
+}
+
+func endpointURL() string {
+	base := strings.TrimRight(strings.TrimSpace(cfg.Server), "/")
+	if strings.HasSuffix(base, "/mcp") {
+		return base
+	}
+	return base + "/mcp"
+}
+
+func newHTTPClient() *http.Client {
+	return &http.Client{
+		Timeout: 0,
+		Transport: &bearerTransport{
+			base:  http.DefaultTransport,
+			token: cfg.Token,
+		},
+	}
+}
+
+type bearerTransport struct {
+	base  http.RoundTripper
+	token string
+}
+
+func (t *bearerTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+	base := t.base
+	if base == nil {
+		base = http.DefaultTransport
+	}
+	clone := req.Clone(req.Context())
+	if strings.TrimSpace(t.token) != "" {
+		clone.Header.Set("Authorization", "Bearer "+t.token)
+	}
+	return base.RoundTrip(clone)
+}
+
+func connectRemote(ctx context.Context) (*mcp.ClientSession, error) {
+	if err := requireServer(); err != nil {
+		return nil, err
+	}
+	client := mcp.NewClient(&mcp.Implementation{Name: "amcs-cli", Version: "0.0.1"}, nil)
+	transport := &mcp.StreamableClientTransport{
+		Endpoint:   endpointURL(),
+		HTTPClient: newHTTPClient(),
+	}
+	ctx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	defer cancel()
+	session, err := client.Connect(ctx, transport, nil)
+	if err != nil {
+		return nil, fmt.Errorf("connect to AMCS server: %w", err)
+	}
+	return session, nil
+}

cmd/amcs-cli/cmd/stdio.go

@@ -0,0 +1,62 @@
+package cmd
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+	"github.com/spf13/cobra"
+)
+
+var stdioCmd = &cobra.Command{
+	Use:   "stdio",
+	Short: "Run a stdio MCP bridge backed by a remote AMCS server",
+	RunE: func(cmd *cobra.Command, _ []string) error {
+		ctx := cmd.Context()
+		remote, err := connectRemote(ctx)
+		if err != nil {
+			return err
+		}
+		defer func() { _ = remote.Close() }()
+
+		tools, err := remote.ListTools(ctx, nil)
+		if err != nil {
+			return fmt.Errorf("load remote tools: %w", err)
+		}
+
+		server := mcp.NewServer(&mcp.Implementation{
+			Name:    "amcs-cli",
+			Title:   "AMCS CLI Bridge",
+			Version: "0.0.1",
+		}, nil)
+
+		for _, tool := range tools.Tools {
+			remoteTool := tool
+			server.AddTool(&mcp.Tool{
+				Name:         remoteTool.Name,
+				Description:  remoteTool.Description,
+				InputSchema:  remoteTool.InputSchema,
+				OutputSchema: remoteTool.OutputSchema,
+				Annotations:  remoteTool.Annotations,
+			}, func(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
+				return remote.CallTool(ctx, &mcp.CallToolParams{
+					Name:      req.Params.Name,
+					Arguments: req.Params.Arguments,
+				})
+			})
+		}
+
+		session, err := server.Connect(ctx, &mcp.StdioTransport{}, nil)
+		if err != nil {
+			return fmt.Errorf("start stdio bridge: %w", err)
+		}
+		defer func() { _ = session.Close() }()
+
+		<-ctx.Done()
+		return nil
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(stdioCmd)
+}

cmd/amcs-cli/cmd/tools.go

@@ -0,0 +1,38 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/spf13/cobra"
+)
+
+var toolsCmd = &cobra.Command{
+	Use:   "tools",
+	Short: "List tools available on the remote AMCS server",
+	RunE: func(cmd *cobra.Command, _ []string) error {
+		session, err := connectRemote(cmd.Context())
+		if err != nil {
+			return err
+		}
+		defer func() { _ = session.Close() }()
+
+		res, err := session.ListTools(cmd.Context(), nil)
+		if err != nil {
+			return fmt.Errorf("list tools: %w", err)
+		}
+
+		w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
+		fmt.Fprintln(w, "NAME\tDESCRIPTION")
+		for _, tool := range res.Tools {
+			fmt.Fprintf(w, "%s\t%s\n", tool.Name, strings.TrimSpace(tool.Description))
+		}
+		return w.Flush()
+	},
+}
+
+func init() {
+	rootCmd.AddCommand(toolsCmd)
+}

cmd/amcs-cli/main.go

@@ -0,0 +1,7 @@
+package main
+
+import "git.warky.dev/wdevs/amcs/cmd/amcs-cli/cmd"
+
+func main() {
+	cmd.Execute()
+}