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 { withToolDiagnostics } from '../lib/observability.js';
import { getAllowedDirectories } from '../lib/path-validation.js';
import {
ListAllowedDirectoriesInputSchema,
ListAllowedDirectoriesOutputSchema,
} from '../schemas.js';
import {
buildToolErrorResponse,
buildToolResponse,
type ToolRegistrationOptions,
type ToolResponse,
type ToolResult,
withToolErrorHandling,
wrapToolHandler,
} from './shared.js';
const LIST_ALLOWED_DIRECTORIES_TOOL = {
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: {
readOnlyHint: true,
idempotentHint: true,
openWorldHint: false,
},
} 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,
} as const;
return buildToolResponse(buildTextRoots(dirs), structured);
}
export function registerListAllowedDirectoriesTool(
server: McpServer,
options: ToolRegistrationOptions = {}
): void {
const handler = (): Promise<
ToolResult<z.infer<typeof ListAllowedDirectoriesOutputSchema>>
> =>
withToolErrorHandling(
() =>
withToolDiagnostics('roots', () =>
Promise.resolve(handleListAllowedDirectories())
),
(error) => buildToolErrorResponse(error, ErrorCode.E_UNKNOWN)
);
server.registerTool(
'roots',
{
...LIST_ALLOWED_DIRECTORIES_TOOL,
...(options.iconInfo
? {
icons: [
{
src: options.iconInfo.src,
mimeType: options.iconInfo.mimeType,
...(options.iconInfo.mimeType === 'image/svg+xml'
? { sizes: ['any'] }
: {}),
},
],
}
: {}),
},
wrapToolHandler(handler, {
guard: options.isInitialized,
progressMessage: () => 'roots',
})
);
}
