feat(mcp): list registered tools

cmd/mcp.go

@@ -2,6 +2,7 @@ package cmd
 
 import (
 	"context"
+	"encoding/json"
 	"fmt"
 	"os"
 	"os/signal"
@@ -66,6 +67,34 @@ Use --socket to serve over a Unix domain socket (future).`,
 	}
 
 	cmd.Flags().StringVar(&socketPath, "socket", "", "Unix socket path for TUI+MCP mode (not yet implemented)")
+	cmd.AddCommand(newMCPToolsCmd())
 
 	return cmd
 }
+
+const mcpToolsUse = "tools"
+
+func newMCPToolsCmd() *cobra.Command {
+	var jsonOut bool
+
+	cmd := &cobra.Command{
+		Use:   mcpToolsUse,
+		Short: "List grut MCP tools",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			tools := grut_mcp.ToolInventory()
+			w := cmd.OutOrStdout()
+			if jsonOut {
+				enc := json.NewEncoder(w)
+				enc.SetIndent("", "  ")
+				return enc.Encode(tools)
+			}
+			fmt.Fprintf(w, "%-24s %-6s %s\n", "NAME", "TYPE", "DESCRIPTION")
+			for _, tool := range tools {
+				fmt.Fprintf(w, "%-24s %-6s %s\n", tool.Name, tool.Category, tool.Description)
+			}
+			return nil
+		},
+	}
+	cmd.Flags().BoolVar(&jsonOut, "json", false, "Print tools as JSON")
+	return cmd
+}

cmd/mcp_tools_test.go

@@ -0,0 +1,40 @@
+package cmd
+
+import (
+	"bytes"
+	"encoding/json"
+	"testing"
+
+	grut_mcp "github.com/jongio/grut/internal/mcp"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMCPToolsCommandListsTools(t *testing.T) {
+	cmd := newMCPCmd()
+	cmd.SetArgs([]string{"tools"})
+	var out bytes.Buffer
+	cmd.SetOut(&out)
+
+	err := cmd.Execute()
+
+	require.NoError(t, err)
+	assert.Contains(t, out.String(), "NAME")
+	assert.Contains(t, out.String(), "git_status")
+	assert.Contains(t, out.String(), "file_read")
+}
+
+func TestMCPToolsCommandJSON(t *testing.T) {
+	cmd := newMCPCmd()
+	cmd.SetArgs([]string{"tools", "--json"})
+	var out bytes.Buffer
+	cmd.SetOut(&out)
+
+	err := cmd.Execute()
+
+	require.NoError(t, err)
+	var tools []grut_mcp.ToolInfo
+	require.NoError(t, json.Unmarshal(out.Bytes(), &tools))
+	assert.NotEmpty(t, tools)
+	assert.Equal(t, "git_status", tools[0].Name)
+}

internal/mcp/inventory.go

@@ -0,0 +1,29 @@
+package mcp
+
+import (
+	"slices"
+
+	mcpserver "github.com/mark3labs/mcp-go/server"
+)
+
+type ToolInfo struct {
+	Name        string `json:"name"`
+	Category    string `json:"category"`
+	Description string `json:"description"`
+}
+
+func ToolInventory() []ToolInfo {
+	s := &Server{
+		mcp: mcpserver.NewMCPServer("grut", "inventory"),
+	}
+	registerGitReadTools(s)
+	registerGitWriteTools(s)
+	registerGitOpsTools(s)
+	registerFileTools(s)
+	return s.Tools()
+}
+
+func (s *Server) Tools() []ToolInfo {
+	out := slices.Clone(s.tools)
+	return out
+}

internal/mcp/inventory_test.go

@@ -0,0 +1,34 @@
+package mcp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestToolInventoryIncludesReadWriteAndFileTools(t *testing.T) {
+	tools := ToolInventory()
+	require.NotEmpty(t, tools)
+
+	byName := make(map[string]ToolInfo, len(tools))
+	for _, tool := range tools {
+		byName[tool.Name] = tool
+	}
+
+	assert.Equal(t, categoryRead, byName["git_status"].Category)
+	assert.Equal(t, categoryWrite, byName["git_stage"].Category)
+	assert.Equal(t, categoryRead, byName["file_read"].Category)
+	assert.Equal(t, categoryWrite, byName["file_write"].Category)
+	assert.NotEmpty(t, byName["git_status"].Description)
+}
+
+func TestServerToolsReturnsCopy(t *testing.T) {
+	tools := ToolInventory()
+	require.NotEmpty(t, tools)
+
+	tools[0].Name = "changed"
+	again := ToolInventory()
+
+	assert.NotEqual(t, "changed", again[0].Name)
+}

internal/mcp/server.go

@@ -30,6 +30,7 @@ type Server struct {
 	limiter  *RateLimiter
 	audit    *AuditLogger
 	repoRoot string
+	tools    []ToolInfo
 }
 
 // Default rate limits (calls per minute) when not configured.
@@ -92,6 +93,11 @@ func (s *Server) MCPServer() *mcpserver.MCPServer {
 
 // addTool registers a tool with security middleware wrapping.
 func (s *Server) addTool(name string, category string, tool mcplib.Tool, handler mcpserver.ToolHandlerFunc) {
+	s.tools = append(s.tools, ToolInfo{
+		Name:        name,
+		Category:    category,
+		Description: tool.Description,
+	})
 	s.mcp.AddTool(tool, s.wrapHandler(name, category, handler))
 }