refactor: Separate ServerTool with HandlerFunc pattern and ToolDependencies

internal/ghmcp/server.go

@@ -151,6 +151,17 @@ func NewMCPServer(cfg MCPServerConfig) (*mcp.Server, error) {
 	ghServer.AddReceivingMiddleware(addGitHubAPIErrorToContext)
 	ghServer.AddReceivingMiddleware(addUserAgentsMiddleware(cfg, restClient, gqlHTTPClient))
 
+	// Create the dependencies struct for tool handlers
+	deps := github.ToolDependencies{
+		GetClient:         getClient,
+		GetGQLClient:      getGQLClient,
+		GetRawClient:      getRawClient,
+		RepoAccessCache:   repoAccessCache,
+		T:                 cfg.Translator,
+		Flags:             github.FeatureFlags{LockdownMode: cfg.LockdownMode},
+		ContentWindowSize: cfg.ContentWindowSize,
+	}
+
 	// Create default toolsets
 	tsg := github.DefaultToolsetGroup(
 		cfg.ReadOnly,
@@ -181,7 +192,7 @@ func NewMCPServer(cfg MCPServerConfig) (*mcp.Server, error) {
 		enabledTools, _ = tsg.ResolveToolAliases(enabledTools)
 
 		// Register the specified tools (additive to any toolsets already enabled)
-		err = tsg.RegisterSpecificTools(ghServer, enabledTools, cfg.ReadOnly)
+		err = tsg.RegisterSpecificTools(ghServer, enabledTools, cfg.ReadOnly, deps)
 		if err != nil {
 			return nil, fmt.Errorf("failed to register tools: %w", err)
 		}

pkg/github/dependencies.go

@@ -0,0 +1,53 @@
+package github
+
+import (
+	"github.com/github/github-mcp-server/pkg/lockdown"
+	"github.com/github/github-mcp-server/pkg/raw"
+	"github.com/github/github-mcp-server/pkg/toolsets"
+	"github.com/github/github-mcp-server/pkg/translations"
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+)
+
+// ToolDependencies contains all dependencies that tool handlers might need.
+// This is a properly-typed struct that lives in pkg/github to avoid circular
+// dependencies. The toolsets package uses `any` for deps and tool handlers
+// type-assert to this struct.
+type ToolDependencies struct {
+	// GetClient returns a GitHub REST API client
+	GetClient GetClientFn
+
+	// GetGQLClient returns a GitHub GraphQL client
+	GetGQLClient GetGQLClientFn
+
+	// GetRawClient returns a raw HTTP client for GitHub
+	GetRawClient raw.GetRawClientFn
+
+	// RepoAccessCache is the lockdown mode repo access cache
+	RepoAccessCache *lockdown.RepoAccessCache
+
+	// T is the translation helper function
+	T translations.TranslationHelperFunc
+
+	// Flags are feature flags
+	Flags FeatureFlags
+
+	// ContentWindowSize is the size of the content window for log truncation
+	ContentWindowSize int
+}
+
+// NewTool creates a ServerTool with fully-typed ToolDependencies.
+// This helper isolates the type assertion from `any` to `ToolDependencies`,
+// so tool implementations remain fully typed without assertions scattered throughout.
+func NewTool[In, Out any](tool mcp.Tool, handler func(deps ToolDependencies) mcp.ToolHandlerFor[In, Out]) toolsets.ServerTool {
+	return toolsets.NewServerTool(tool, func(d any) mcp.ToolHandlerFor[In, Out] {
+		return handler(d.(ToolDependencies))
+	})
+}
+
+// NewToolFromHandler creates a ServerTool with fully-typed ToolDependencies
+// for handlers that conform to mcp.ToolHandler directly.
+func NewToolFromHandler(tool mcp.Tool, handler func(deps ToolDependencies) mcp.ToolHandler) toolsets.ServerTool {
+	return toolsets.NewServerToolFromHandler(tool, func(d any) mcp.ToolHandler {
+		return handler(d.(ToolDependencies))
+	})
+}

pkg/github/dynamic_tools.go

@@ -61,9 +61,7 @@ func EnableToolset(s *mcp.Server, toolsetGroup *toolsets.ToolsetGroup, t transla
 			//
 			// Send notification to all initialized sessions
 			// s.sendNotificationToAllClients("notifications/tools/list_changed", nil)
-			for _, serverTool := range toolset.GetActiveTools() {
-				serverTool.RegisterFunc(s)
-			}
+			toolset.RegisterTools(s)
 
 			return utils.NewToolResultText(fmt.Sprintf("Toolset %s enabled", toolsetName)), nil, nil
 		})