can1357/oh-my-pi · error

Invalid ${label}

Error message

Invalid ${label}

What it means

The lightweight runtime validator in packages/utils/src/acp/schema.ts wraps a boolean check function with a Zod-compatible surface. Its 'parse' method throws Error(`Invalid ${label}`) when the value fails the structural check for the labeled schema (e.g. a session/prompt response shape). safeParse returns the same message as an issue without throwing.

Source

Thrown at packages/utils/src/acp/schema.ts:37

export interface ValidationFailure {
	success: false;
	error: ValidationError;
}
/** Runtime validator compatible with the used schema call shape. */
export interface Validator<T> {
	safeParse(value: unknown): ValidationSuccess<T> | ValidationFailure;
	parse(value: unknown): T;
}

function validator<T>(check: (value: unknown) => boolean, label: string): Validator<T> {
	return {
		safeParse(value) {
			return check(value)
				? { success: true, data: value as T }
				: { success: false, error: { issues: [{ path: [], message: `Invalid ${label}` }] } };
		},
		parse(value) {
			if (!check(value)) throw new Error(`Invalid ${label}`);
			return value as T;
		},
	};
}

function objectWithString(value: unknown, key: string): boolean {
	return typeof value === "object" && value !== null && typeof (value as Record<string, unknown>)[key] === "string";
}

function validModes(value: unknown): boolean {
	if (value === undefined || value === null) return true;
	if (typeof value !== "object" || value === null) return false;
	const modes = value as Record<string, unknown>;
	return (
		typeof modes.currentModeId === "string" &&
		Array.isArray(modes.availableModes) &&
		modes.availableModes.every(mode => objectWithString(mode, "id") && objectWithString(mode, "name"))
	);

View on GitHub (pinned to 9690622007)

Solutions

1. Log/inspect the raw value passed to parse and compare it against the schema's required fields.
2. Use safeParse instead of parse to get a structured failure (issues array) instead of a throw, and branch on success.
3. Upgrade or align the peer (agent/client) so both sides speak the same ACP protocol revision.
4. Handle protocol error responses before handing payloads to the schema validator.

Example fix

// before
const response = schema.parse(raw);
// after
const result = schema.safeParse(raw);
if (!result.success) throw new Error(`Bad agent response: ${result.error.issues[0]?.message}`);
const response = result.data;

const result = schema.safeParse(raw);
if (!result.success) {
  console.error("ACP response rejected:", result.error.issues);
  return null;
}
const response = result.data;

function isObjectWithString(v: unknown, key: string): v is Record<string, string> {
  return typeof v === "object" && v !== null && !Array.isArray(v) && typeof (v as Record<string, unknown>)[key] === "string";
}

try {
  return schema.parse(raw);
} catch (err) {
  if (err instanceof Error && err.message.startsWith("Invalid ")) {
    throw new Error(`ACP schema violation: ${err.message}; payload=${JSON.stringify(raw).slice(0, 200)}`);
  }
  throw err;
}

When it happens

Trigger: Calling parse(value) on an ACP protocol response (NewSessionResponse, LoadSessionResponse, PromptResponse, ForkSessionResponse, SessionNotification) that is missing required string fields, is not an object, is an array, or has malformed nested structures (e.g. modes.currentModeId not a string, availableModes entries lacking string id/name).

Common situations: An ACP agent or client peer returning a non-conformant response after a version drift between protocol revisions; a custom agent implementation missing required response fields; response JSON parsed from stdout lines that contains an error object instead of the expected success shape.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Invalid JSON-RPC message
• tasks must be a list
• cycle_model response did not include a model
• ready.supportedProtocolVersions must be integers
• Replacement text is not valid UTF-8: {err}

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/bea5f22477754237. Report an issue: GitHub.