can1357/oh-my-pi · error · ToolError

Invalid cmux socket response: expected object

Error message

Invalid cmux socket response: expected object

What it means

After a reply line parses as JSON, #parseResponse requires the payload to be a JSON object. Scalars, arrays, strings, or null payloads cannot carry the {ok, result, error} envelope, so this ToolError is thrown. It signals the peer speaks JSON but not the cmux response envelope.

Source

Thrown at packages/coding-agent/src/tools/browser/cmux/socket-client.ts:394

				line = line.slice(0, -1);
			}
			const waiter = this.#lineWaiters.shift();
			waiter?.resolve(line);
		}
	}

	#parseResponse(line: string): Record<string, unknown> {
		if (line.startsWith("ERROR:")) {
			throw new ToolError(line);
		}
		let payload: unknown;
		try {
			payload = JSON.parse(line);
		} catch (err) {
			throw new ToolError(`Invalid cmux socket JSON response: ${err instanceof Error ? err.message : String(err)}`);
		}
		if (!payload || typeof payload !== "object") {
			throw new ToolError("Invalid cmux socket response: expected object");
		}
		const response = payload as { ok?: unknown; result?: unknown; error?: CmuxErrorPayload };
		if (response.ok === true) {
			return (response.result ?? {}) as Record<string, unknown>;
		}
		if (response.ok === false) {
			throw new ToolError(formatCmuxError(response.error));
		}
		throw new ToolError("Invalid cmux socket response: missing ok flag");
	}

	#handleSocketFailure(err: Error): void {
		if (this.#disposed) return;
		this.#connected = false;
		this.#connectPromise = null;
		this.#rejectAll(new ToolError(`cmux socket error: ${err.message}`));
		this.#socket?.destroy();
		this.#socket = null;

View on GitHub (pinned to 9690622007)

Solutions

1. Confirm the endpoint is the cmux daemon and the method is expected to return the {ok,...} envelope
2. Upgrade or downgrade the daemon so client/server protocol versions align
3. Inspect the raw reply (enable socket logging) to see what shape came back, then correct the caller or file a daemon bug

function isCmuxEnvelope(v: unknown): v is { ok: boolean; result?: unknown; error?: { code?: string; message?: string; details?: unknown } } {
  return typeof v === "object" && v !== null && "ok" in v && typeof (v as { ok: unknown }).ok === "boolean";
}

try {
  return await client.request(method, params);
} catch (err) {
  if (err instanceof ToolError && err.message === "Invalid cmux socket response: expected object") {
    // peer is not speaking the cmux envelope: check endpoint and protocol version
  }
  throw err;
}

When it happens

Trigger: Daemon returns a bare JSON array/string/null for a method; a different JSON-RPC-ish service on the socket replies with non-envelope JSON (e.g. {"jsonrpc":"2.0",...} without ok, or plain [1,2,3]).

Common situations: Pointing the client at a non-cmux JSON service on the same path/port; daemon regression emitting envelopes without ok for some methods; protocol version skew after an upgrade.

Related errors

• Invalid cmux socket response: missing ok flag
• Replacement text is not valid UTF-8: {err}
• Missing or invalid field "${field}" in catalog: ${filePath}
• Marketplace catalog at ${filePath} must be a JSON object
• rpc frame must be an object

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/6299142cba1b372b. Report an issue: GitHub.