import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import { z } from 'zod';
import { runGxi, escapeSchemeString, ERROR_MARKER, VALID_MARKER } from '../gxi.js';
interface SnippetResult {
id: string;
valid: boolean;
error?: string;
}
export function registerBatchSyntaxCheckTool(server: McpServer): void {
server.registerTool(
'gerbil_batch_syntax_check',
{
title: 'Batch Syntax Check',
description:
'Check multiple Gerbil code snippets for syntax validity in a single call. ' +
'Returns per-snippet pass/fail results. Much more efficient than making individual ' +
'gerbil_check_syntax calls when verifying many functions or definitions at once.',
annotations: {
readOnlyHint: true,
idempotentHint: true,
},
inputSchema: {
snippets: z
.array(z.object({
id: z.string().describe('Identifier for this snippet (e.g. function name)'),
code: z.string().describe('Gerbil code to check'),
}))
.describe('Array of code snippets to check'),
},
},
async ({ snippets }) => {
if (!snippets || snippets.length === 0) {
return {
content: [{
type: 'text' as const,
text: 'No snippets provided.',
}],
isError: true,
};
}
const results: SnippetResult[] = [];
// Process snippets in batches to avoid overwhelming gxi
// Each snippet gets its own gxi call for isolation
const CONCURRENCY = 5;
for (let i = 0; i < snippets.length; i += CONCURRENCY) {
const batch = snippets.slice(i, i + CONCURRENCY);
const promises = batch.map(async (snippet) => {
const escaped = escapeSchemeString(snippet.code);
const exprs = [
'(import :gerbil/expander)',
[
'(with-catch',
' (lambda (e)',
` (display "${ERROR_MARKER}")`,
' (display-exception e (current-output-port)))',
' (lambda ()',
` (read (open-input-string "${escaped}"))`,
` (displayln "${VALID_MARKER}")))`,
].join(' '),
];
try {
const result = await runGxi(exprs, { timeout: 10000 });
const stdout = result.stdout;
if (stdout.includes(ERROR_MARKER)) {
const errorMsg = stdout.slice(stdout.indexOf(ERROR_MARKER) + ERROR_MARKER.length).trim();
return {
id: snippet.id,
valid: false,
error: errorMsg.split('\n')[0],
};
}
return { id: snippet.id, valid: true };
} catch (err) {
return {
id: snippet.id,
valid: false,
error: err instanceof Error ? err.message : 'Check failed',
};
}
});
const batchResults = await Promise.all(promises);
results.push(...batchResults);
}
// Format output
const passed = results.filter(r => r.valid).length;
const failed = results.filter(r => !r.valid).length;
const sections: string[] = [
`Checked ${results.length} snippet(s): ${passed} passed, ${failed} failed`,
'',
];
for (const r of results) {
if (r.valid) {
sections.push(` [PASS] ${r.id}`);
} else {
sections.push(` [FAIL] ${r.id}: ${r.error}`);
}
}
return {
content: [{ type: 'text' as const, text: sections.join('\n') }],
isError: failed > 0,
};
},
);
}
