feat(mcp): add mcp list-tools to list available tool calls

cmd/src/mcp.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+
+	"github.com/sourcegraph/src-cli/internal/mcp"
+)
+
+func init() {
+	flagSet := flag.NewFlagSet("mcp", flag.ExitOnError)
+	commands = append(commands, &command{
+		flagSet: flagSet,
+		handler: mcpMain,
+	})
+}
+func mcpMain(args []string) error {
+	fmt.Println("NOTE: This command is still experimental")
+	tools, err := mcp.LoadToolDefinitions()
+	if err != nil {
+		return err
+	}
+
+	subcmd := args[0]
+	if subcmd == "list-tools" {
+		fmt.Println("Available tools")
+		for name := range tools {
+			fmt.Printf("- %s\n", name)
+		}
+		return nil
+	}
+
+	tool, ok := tools[subcmd]
+	if !ok {
+		return fmt.Errorf("tool definition for %q not found - run src mcp list-tools to see a list of available tools", subcmd)
+	}
+	return handleMcpTool(tool, args[1:])
+}
+
+func handleMcpTool(tool *mcp.ToolDef, args []string) error {
+	fmt.Printf("handling tool %q args: %+v", tool.Name, args)
+	return nil
+}

internal/mcp/mcp_parse.go

@@ -4,13 +4,13 @@ package mcp
 import (
 	_ "embed"
 	"encoding/json"
-	"fmt"
+	"strings"
 
 	"github.com/sourcegraph/sourcegraph/lib/errors"
 )
 
 //go:embed mcp_tools.json
-var _ []byte
+var mcpToolListJSON []byte
 
 type ToolDef struct {
 	Name         string `json:"name"`
@@ -67,7 +67,11 @@ type parser struct {
 	errors []error
 }
 
-func LoadToolDefinitions(data []byte) (map[string]*ToolDef, error) {
+func LoadToolDefinitions() (map[string]*ToolDef, error) {
+	return loadToolDefinitions(mcpToolListJSON)
+}
+
+func loadToolDefinitions(data []byte) (map[string]*ToolDef, error) {
 	defs := struct {
 		Tools []struct {
 			Name         string    `json:"name"`
@@ -85,7 +89,8 @@ func LoadToolDefinitions(data []byte) (map[string]*ToolDef, error) {
 	parser := &parser{}
 
 	for _, t := range defs.Tools {
-		tools[t.Name] = &ToolDef{
+		name := normalizeToolName(t.Name)
+		tools[name] = &ToolDef{
 			Name:         t.Name,
 			Description:  t.Description,
 			InputSchema:  parser.parseRootSchema(t.InputSchema),
@@ -157,10 +162,16 @@ func (p *parser) parseProperties(props map[string]json.RawMessage) map[string]Sc
 	for name, raw := range props {
 		var r RawSchema
 		if err := json.Unmarshal(raw, &r); err != nil {
-			p.errors = append(p.errors, fmt.Errorf("failed to parse property %q: %w", name, err))
+			p.errors = append(p.errors, errors.Newf("failed to parse property %q: %w", name, err))
 			continue
 		}
 		res[name] = p.parseSchema(&r)
 	}
 	return res
 }
+
+// normalizeToolName takes mcp tool names like 'sg_keyword_search' and normalizes it to 'keyword-search"
+func normalizeToolName(toolName string) string {
+	toolName, _ = strings.CutPrefix(toolName, "sg_")
+	return strings.ReplaceAll(toolName, "_", "-")
+}

internal/mcp/mcp_parse_test.go

@@ -37,7 +37,7 @@ func TestLoadToolDefinitions(t *testing.T) {
 	  ]
 	}`)
 
-	tools, err := LoadToolDefinitions(toolJSON)
+	tools, err := loadToolDefinitions(toolJSON)
 	if err != nil {
 		t.Fatalf("Failed to load tool definitions: %v", err)
 	}
@@ -46,7 +46,8 @@ func TestLoadToolDefinitions(t *testing.T) {
 		t.Fatalf("Expected 1 tool, got %d", len(tools))
 	}
 
-	tool := tools["test_tool"]
+	// Temporary: map keys have normalized names
+	tool := tools["test-tool"]
 	if tool == nil {
 		t.Fatal("Tool 'test_tool' not found")
 	}