import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import type { z } from 'zod';
import { joinLines } from '../config.js';
import { ErrorCode } from '../lib/errors.js';
import { getAllowedDirectories } from '../lib/path-validation.js';
import {
ListAllowedDirectoriesInputSchema,
ListAllowedDirectoriesOutputSchema,
} from '../schemas.js';
import {
buildToolErrorResponse,
buildToolResponse,
executeToolWithDiagnostics,
READ_ONLY_TOOL_ANNOTATIONS,
type ToolContract,
type ToolExtra,
type ToolRegistrationOptions,
type ToolResponse,
type ToolResult,
withDefaultIcons,
withValidatedArgs,
wrapToolHandler,
} from './shared.js';
import { registerToolTaskIfAvailable } from './task-support.js';
export const LIST_ALLOWED_DIRECTORIES_TOOL: ToolContract = {
name: 'roots',
title: 'Workspace Roots',
description:
'List the workspace roots this server can access. ' +
'Call this first to see available directories. ' +
'All other tools only work within these directories.',
inputSchema: ListAllowedDirectoriesInputSchema,
outputSchema: ListAllowedDirectoriesOutputSchema,
annotations: READ_ONLY_TOOL_ANNOTATIONS,
nuances: ['Other tools are constrained to these roots.'],
} as const;
function buildTextRoots(dirs: string[]): string {
if (dirs.length === 0) {
return 'No directories configured';
}
return joinLines([
`${dirs.length} workspace roots:`,
...dirs.map((d) => ` ${d}`),
]);
}
function handleListAllowedDirectories(): ToolResponse<
z.infer<typeof ListAllowedDirectoriesOutputSchema>
> {
const dirs = getAllowedDirectories();
const structured = {
ok: true,
directories: dirs,
rootsCount: dirs.length,
hasMultipleRoots: dirs.length > 1,
} as const;
return buildToolResponse(buildTextRoots(dirs), structured);
}
export function registerListAllowedDirectoriesTool(
server: McpServer,
options: ToolRegistrationOptions = {}
): void {
const handler = (
_args: z.infer<typeof ListAllowedDirectoriesInputSchema>,
extra: ToolExtra
): Promise<ToolResult<z.infer<typeof ListAllowedDirectoriesOutputSchema>>> =>
executeToolWithDiagnostics({
toolName: 'roots',
extra,
run: () => handleListAllowedDirectories(),
onError: (error) => buildToolErrorResponse(error, ErrorCode.E_UNKNOWN),
});
const wrappedHandler = wrapToolHandler(handler, {
guard: options.isInitialized,
progressMessage: () => '≣ roots',
completionMessage: (_args, result) => {
if (result.isError) return `≣ roots • failed`;
const sc = result.structuredContent;
if (!sc.ok) return `≣ roots • failed`;
const count = sc.rootsCount ?? 0;
return `≣ roots • ${count} ${count === 1 ? 'root' : 'roots'}`;
},
});
const validatedHandler = withValidatedArgs(
ListAllowedDirectoriesInputSchema,
wrappedHandler
);
if (
registerToolTaskIfAvailable(
server,
'roots',
LIST_ALLOWED_DIRECTORIES_TOOL,
validatedHandler,
options.iconInfo,
options.isInitialized
)
)
return;
server.registerTool(
'roots',
withDefaultIcons({ ...LIST_ALLOWED_DIRECTORIES_TOOL }, options.iconInfo),
validatedHandler
);
}
