feat: add fork filter parameter to repository search functionality

README.md

@@ -346,6 +346,7 @@ export GITHUB_MCP_TOOL_ADD_ISSUE_COMMENT_DESCRIPTION="an alternative description
   - `query`: Search query (string, required)
   - `sort`: Sort field (string, optional)
   - `order`: Sort order (string, optional)
+  - `fork`: Fork filter: 'true' to include forks, 'only' to show only forks, 'false' to exclude forks (default) (string, optional)
   - `page`: Page number (number, optional)
   - `perPage`: Results per page (number, optional)
 

pkg/github/search.go

@@ -5,13 +5,21 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"strings"
 
 	"github.com/github/github-mcp-server/pkg/translations"
 	"github.com/google/go-github/v69/github"
 	"github.com/mark3labs/mcp-go/mcp"
 	"github.com/mark3labs/mcp-go/server"
 )
 
+// containsForkFilter checks if a query already contains a fork filter.
+// This prevents duplicate or conflicting fork filters in the query.
+func containsForkFilter(query string) bool {
+	query = strings.ToLower(query)
+	return strings.Contains(query, " fork:") || strings.HasPrefix(query, "fork:")
+}
+
 // SearchRepositories creates a tool to search for GitHub repositories.
 func SearchRepositories(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc) {
 	return mcp.NewTool("search_repositories",
@@ -20,18 +28,37 @@ func SearchRepositories(getClient GetClientFn, t translations.TranslationHelperF
 				mcp.Required(),
 				mcp.Description("Search query"),
 			),
+			mcp.WithString("fork",
+				mcp.Description("Fork filter: 'true' to include forks, 'only' to show only forks, 'false' to exclude forks (default)"),
+				mcp.Enum("true", "only", "false"),
+			),
 			WithPagination(),
 		),
 		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
 			query, err := requiredParam[string](request, "query")
 			if err != nil {
 				return mcp.NewToolResultError(err.Error()), nil
 			}
+			fork, err := OptionalParam[string](request, "fork")
+			if err != nil {
+				return mcp.NewToolResultError(err.Error()), nil
+			}
 			pagination, err := OptionalPaginationParams(request)
 			if err != nil {
 				return mcp.NewToolResultError(err.Error()), nil
 			}
 
+			// Modify query to include fork parameter if specified
+			if fork != "" {
+				// GitHub API supports 'fork:true', 'fork:only', and absence for excluding forks
+				if fork == "true" || fork == "only" {
+					// Check if the query already contains a fork filter
+					if !containsForkFilter(query) {
+						query = query + " fork:" + fork
+					}
+				}
+			}
+
 			opts := &github.SearchOptions{
 				ListOptions: github.ListOptions{
 					Page:    pagination.page,

pkg/github/search_test.go

@@ -88,6 +88,8 @@ func Test_SearchRepositories(t *testing.T) {
 						"q":        "golang test",
 						"page":     "1",
 						"per_page": "30",
+						// Note: Not specifying 'fork' parameter here, which verifies that
+						// when 'fork' is not provided in the request, it's not added to the query parameters
 					}).andThen(
 						mockResponse(t, http.StatusOK, mockSearchResult),
 					),
@@ -99,6 +101,69 @@ func Test_SearchRepositories(t *testing.T) {
 			expectError:    false,
 			expectedResult: mockSearchResult,
 		},
+		{
+			name: "repository search with fork parameter",
+			mockedClient: mock.NewMockedHTTPClient(
+				mock.WithRequestMatchHandler(
+					mock.GetSearchRepositories,
+					expectQueryParams(t, map[string]string{
+						"q":        "golang test fork:only",
+						"page":     "1",
+						"per_page": "30",
+					}).andThen(
+						mockResponse(t, http.StatusOK, mockSearchResult),
+					),
+				),
+			),
+			requestArgs: map[string]interface{}{
+				"query": "golang test",
+				"fork":  "only",
+			},
+			expectError:    false,
+			expectedResult: mockSearchResult,
+		},
+		{
+			name: "repository search with fork parameter (true)",
+			mockedClient: mock.NewMockedHTTPClient(
+				mock.WithRequestMatchHandler(
+					mock.GetSearchRepositories,
+					expectQueryParams(t, map[string]string{
+						"q":        "golang test fork:true",
+						"page":     "1",
+						"per_page": "30",
+					}).andThen(
+						mockResponse(t, http.StatusOK, mockSearchResult),
+					),
+				),
+			),
+			requestArgs: map[string]interface{}{
+				"query": "golang test",
+				"fork":  "true",
+			},
+			expectError:    false,
+			expectedResult: mockSearchResult,
+		},
+		{
+			name: "repository search with fork parameter (false)",
+			mockedClient: mock.NewMockedHTTPClient(
+				mock.WithRequestMatchHandler(
+					mock.GetSearchRepositories,
+					expectQueryParams(t, map[string]string{
+						"q":        "golang test",
+						"page":     "1",
+						"per_page": "30",
+					}).andThen(
+						mockResponse(t, http.StatusOK, mockSearchResult),
+					),
+				),
+			),
+			requestArgs: map[string]interface{}{
+				"query": "golang test",
+				"fork":  "false",
+			},
+			expectError:    false,
+			expectedResult: mockSearchResult,
+		},
 		{
 			name: "search fails",
 			mockedClient: mock.NewMockedHTTPClient(