API endpoints that materialize on demand

// @mode serverless
// @ai true
// @ai-model anthropic/claude-sonnet-4.5

const path = '/' + (metadata.parameters.slug ?? []).join('/');
const body = req.body ?? []'';

// Already saved? Hand off to the cached route.
const saved = await fs.exists('scripts/1/api' + path + '.ts');
if (saved) return fetch(path, [ method: metadata.method, body ]);

// Otherwise: ask for a handler, sandbox it, save it.
const [ text: handler ] = await generateText([
  model,
  system: 'Return a JS handler body. No imports. Return JSON.',
  prompt: `URL $[metadata.method] $[path]\nQuery $[JSON.stringify(metadata.query)]\nBody $[JSON.stringify(body)]`,
]);

const result = await isolate.eval(handler, [ req, res, fetch ]);
await fs.write('scripts/1/api' + path + '.ts', '// @mode serverless\n' + handler);
return result;