What causes "NotebookLM RPC ${rpcId} returned malformed JSON" in jackwener/OpenCLI?

Retry from a stable connection — truncation/corruption is often transient

jackwener/OpenCLI · error · CliError

NOTEBOOKLM_RPC_SCHEMA

NOTEBOOKLM_RPC_SCHEMA

Error message

NotebookLM RPC ${rpcId} returned malformed JSON

What it means

When the matching 'wrb.fr' frame for the requested rpcId is found, its payload is expected to be a JSON string (or already-parsed value). If JSON.parse of the string payload throws, the library raises CliError code NOTEBOOKLM_RPC_SCHEMA indicating the response body is not parseable JSON — the internal response shape or encoding changed. This is a contract violation between the page's RPC layer and the CLI's parser.

Source

Thrown at clis/notebooklm/rpc.js:169

            if (item[0] === 'er') {
                const errorCode = typeof item[2] === 'number'
                    ? item[2]
                    : typeof item[5] === 'number'
                        ? item[5]
                        : null;
                if (errorCode === 401 || errorCode === 403) {
                    throw new AuthRequiredError(NOTEBOOKLM_DOMAIN, `NotebookLM RPC returned auth error (${errorCode})`);
                }
                throw new CliError('NOTEBOOKLM_RPC', `NotebookLM RPC failed${errorCode ? ` (code=${errorCode})` : ''}`, 'Retry from an already logged-in NotebookLM session, or inspect the raw response with debug logging.');
            }
            if (item[0] === 'wrb.fr' && item[1] === rpcId) {
                const payload = item[2];
                if (typeof payload === 'string') {
                    try {
                        return JSON.parse(payload);
                    }
                    catch {
                        throw new CliError('NOTEBOOKLM_RPC_SCHEMA', `NotebookLM RPC ${rpcId} returned malformed JSON`, 'Retry from the NotebookLM page; the internal RPC response shape may have changed.');
                    }
                }
                return payload;
            }
        }
    }
    throw new CliError('NOTEBOOKLM_RPC_SCHEMA', `NotebookLM RPC ${rpcId} returned no matching response frame`, 'Retry from the NotebookLM page; the internal RPC response shape may have changed.');
}
export async function fetchNotebooklmInPage(page, url, options = {}) {
    const method = options.method ?? 'GET';
    const headers = options.headers ?? {};
    const body = options.body ?? '';
    let evaluated;
    try {
        evaluated = await page.evaluate(`(async () => {
    const request = {
      url: ${JSON.stringify(url)},
      method: ${JSON.stringify(method)},

View on GitHub (pinned to 49907e53dc)

Solutions

Retry from a stable connection — truncation/corruption is often transient
Enable debug logging to capture the raw payload and see why it fails to parse
Update the CLI if NotebookLM changed its internal response encoding
Check proxies/VPN that might rewrite or truncate response bodies

Example fix

// before (parsing without protection)
const data = JSON.parse(payload);
// after (tolerant parse)
let data;
try { data = JSON.parse(payload); } catch { throw new Error('malformed rpc payload: ' + payload.slice(0, 80)); }

Defensive patterns

Strategy: retry

Validate before calling

// retry only parse failures; bail on others
const result = await withRetry(3, () => callNotebooklmRpc(page, rpcId, payload),
  e => e.code === 'NOTEBOOKLM_RPC_SCHEMA');

Type guard

function isSchemaParseError(e) {
  return e instanceof Error && e.code === 'NOTEBOOKLM_RPC_SCHEMA' && /malformed JSON/.test(e.message);
}

Try / catch

try {
  data = await callNotebooklmRpc(page, rpcId, payload);
} catch (e) {
  if (isSchemaParseError(e)) {
    console.error('Malformed JSON from RPC — check network/proxy truncation and CLI version.');
  } else throw e;
}

Prevention

Use a stable connection; avoid proxies that truncate/rewrite responses
Retry once on parse failures — truncation is often transient
Update the CLI when the error recurs, as encoding changes accompany frontend updates

When it happens

Trigger: extractNotebooklmRpcResult finds item[0]==='wrb.fr' && item[1]===rpcId, payload is a string, but JSON.parse(payload) throws — truncated response, HTML error page embedded as payload, or a serialization change in the frame.

Common situations: Response truncated by a proxy or flaky network; Google served an HTML error/interstitial inside the frame; NotebookLM frontend update changed payload encoding; character-set issues mangling the JSON.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of jackwener/OpenCLI@49907e53dc (2026-08-29). Data as JSON: /api/errors/19fa7907482cdade. Report an issue: GitHub.