paperclipai/paperclip · warning · Error

Request body too large.

Error message

Request body too large.

What it means

Identical guard to the google-sheets server: readJsonBody in the kv-demo MCP HTTP layer caps total streamed body at 1,000,000 bytes and throws mid-stream. The kv-demo store API is small but the same cap applies to MCP requests and to bulk set operations.

Source

Thrown at packages/kv-demo-mcp-server/src/http.ts:52

    "content-type": "text/html; charset=utf-8",
    "content-length": Buffer.byteLength(html),
  });
  res.end(html);
}

function presentedToken(req: IncomingMessage): string | null {
  const header = req.headers.authorization;
  if (header && header.startsWith("Bearer ")) return header.slice("Bearer ".length).trim();
  return null;
}

async function readJsonBody(req: IncomingMessage): Promise<unknown> {
  const chunks: Buffer[] = [];
  let size = 0;
  for await (const chunk of req) {
    const buffer = chunk as Buffer;
    size += buffer.length;
    if (size > 1_000_000) throw new Error("Request body too large.");
    chunks.push(buffer);
  }
  if (chunks.length === 0) return undefined;
  const raw = Buffer.concat(chunks).toString("utf8").trim();
  if (!raw) return undefined;
  return JSON.parse(raw);
}

async function handleMcp(
  req: IncomingMessage,
  res: ServerResponse,
  store: KvStore,
): Promise<void> {
  // Stateless: a fresh MCP server + transport per request. The shared store is
  // what carries state between calls, so no session bookkeeping is needed.
  let parsedBody: unknown;
  try {
    parsedBody = req.method === "POST" ? await readJsonBody(req) : undefined;

View on GitHub (pinned to 67001ec6eb)

Solutions

1. Store the large value out-of-band and keep only a reference in the KV store.
2. Chunk the value across multiple keys.
3. If genuinely needed, fork and raise the 1_000_000 literal.

Example fix

// before
await set('big', hugeJsonString)  // > 1MiB -> error
// after
await set('big.ref', uploadLargeBlobElsewhere(hugeJsonString))

function under1MiB(payload: unknown): boolean {
  return Buffer.byteLength(JSON.stringify(payload), 'utf8') <= 1_000_000;
}

When it happens

Trigger: Any request to the kv-demo HTTP endpoint whose body exceeds 1 MiB — typically a POST /api/state with a very large value, a bulk set, or an MCP tools/call with oversized arguments.

Common situations: Storing a large blob (image base64, big JSON document) as a single KV value; a client retrying with an ever-growing payload.

Related errors

• Request body too large.
• HTTP ${status}
• API error ${response.status}: ${message}
• Request failed with status ${response.status}
• API error ${response.status}: ${bytes.toString("utf8")}

AI-assisted analysis of paperclipai/paperclip@67001ec6eb (2026-08-12). Data as JSON: /api/errors/1822c458e32f843c. Report an issue: GitHub.