> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/agentclientprotocol/typescript-sdk/llms.txt
> Use this file to discover all available pages before exploring further.

# RequestError Class

> JSON-RPC error handling for ACP requests

## Overview

The `RequestError` class represents errors that occur during JSON-RPC method execution in ACP connections. It follows the JSON-RPC 2.0 error object specification and provides static factory methods for creating standard error types.

## Constructor

```typescript theme={null}
constructor(
  public code: number,
  message: string,
  data?: unknown
)
```

Creates a new RequestError with the specified error code, message, and optional additional data.

**Parameters:**

* `code` (number) - The JSON-RPC error code
* `message` (string) - Human-readable error message
* `data` (unknown, optional) - Additional error information

## Properties

### code

```typescript theme={null}
code: number
```

The numeric error code following JSON-RPC 2.0 conventions.

### message

```typescript theme={null}
message: string
```

Human-readable description of the error.

### data

```typescript theme={null}
data?: unknown
```

Optional additional information about the error, such as validation details or context.

## Static Factory Methods

### parseError

```typescript theme={null}
static parseError(data?: unknown, additionalMessage?: string): RequestError
```

Creates a parse error (code: `-32700`).

Invalid JSON was received by the server. An error occurred on the server while parsing the JSON text.

**Parameters:**

* `data` (unknown, optional) - Additional error data
* `additionalMessage` (string, optional) - Additional context to append to the error message

**Returns:** RequestError with code `-32700`

**Example:**

```typescript theme={null}
throw RequestError.parseError({ received: invalidJson });
```

### invalidRequest

```typescript theme={null}
static invalidRequest(data?: unknown, additionalMessage?: string): RequestError
```

Creates an invalid request error (code: `-32600`).

The JSON sent is not a valid Request object.

**Parameters:**

* `data` (unknown, optional) - Additional error data
* `additionalMessage` (string, optional) - Additional context to append to the error message

**Returns:** RequestError with code `-32600`

**Example:**

```typescript theme={null}
throw RequestError.invalidRequest({ reason: "Missing required field 'id'" });
```

### methodNotFound

```typescript theme={null}
static methodNotFound(method: string): RequestError
```

Creates a method not found error (code: `-32601`).

The method does not exist or is not available.

**Parameters:**

* `method` (string) - The method name that was not found

**Returns:** RequestError with code `-32601` and the method name in data

**Example:**

```typescript theme={null}
throw RequestError.methodNotFound("unknown/method");
```

### invalidParams

```typescript theme={null}
static invalidParams(data?: unknown, additionalMessage?: string): RequestError
```

Creates an invalid params error (code: `-32602`).

Invalid method parameter(s).

**Parameters:**

* `data` (unknown, optional) - Additional error data (often validation details)
* `additionalMessage` (string, optional) - Additional context to append to the error message

**Returns:** RequestError with code `-32602`

**Example:**

```typescript theme={null}
throw RequestError.invalidParams(zodError.format());
```

### internalError

```typescript theme={null}
static internalError(data?: unknown, additionalMessage?: string): RequestError
```

Creates an internal error (code: `-32603`).

Internal JSON-RPC error.

**Parameters:**

* `data` (unknown, optional) - Additional error data
* `additionalMessage` (string, optional) - Additional context to append to the error message

**Returns:** RequestError with code `-32603`

**Example:**

```typescript theme={null}
throw RequestError.internalError({ details: error.message });
```

### authRequired

```typescript theme={null}
static authRequired(data?: unknown, additionalMessage?: string): RequestError
```

Creates an authentication required error (code: `-32000`).

**Parameters:**

* `data` (unknown, optional) - Additional error data
* `additionalMessage` (string, optional) - Additional context to append to the error message

**Returns:** RequestError with code `-32000`

**Example:**

```typescript theme={null}
throw RequestError.authRequired({ authMethods: ["oauth"] });
```

### resourceNotFound

```typescript theme={null}
static resourceNotFound(uri?: string): RequestError
```

Creates a resource not found error (code: `-32002`).

Resource, such as a file, was not found.

**Parameters:**

* `uri` (string, optional) - The URI of the missing resource

**Returns:** RequestError with code `-32002` and URI in data (if provided)

**Example:**

```typescript theme={null}
throw RequestError.resourceNotFound("/path/to/missing/file.txt");
```

## Instance Methods

### toResult

```typescript theme={null}
toResult<T>(): Result<T>
```

Converts the RequestError to a JSON-RPC Result object with an error field.

**Returns:** A Result object containing the error information

**Example:**

```typescript theme={null}
const error = RequestError.methodNotFound("test/method");
return error.toResult();
// Returns: { error: { code: -32601, message: "Method not found: test/method", data: { method: "test/method" } } }
```

### toErrorResponse

```typescript theme={null}
toErrorResponse(): ErrorResponse
```

Converts the RequestError to a JSON-RPC ErrorResponse object.

**Returns:** An ErrorResponse object with code, message, and optional data

**Example:**

```typescript theme={null}
const error = RequestError.invalidParams({ field: "sessionId" });
const errorResponse = error.toErrorResponse();
// Returns: { code: -32602, message: "Invalid params", data: { field: "sessionId" } }
```

## Usage in Request Handlers

```typescript theme={null}
const requestHandler = async (method: string, params: unknown): Promise<unknown> => {
  // Method not found
  if (method === "unknown/method") {
    throw RequestError.methodNotFound(method);
  }

  // Invalid parameters
  try {
    const validatedParams = schema.parse(params);
  } catch (error) {
    throw RequestError.invalidParams(error.format());
  }

  // Resource not found
  const file = await readFile(uri);
  if (!file) {
    throw RequestError.resourceNotFound(uri);
  }

  // Authentication required
  if (!isAuthenticated) {
    throw RequestError.authRequired();
  }

  return result;
};
```

## See Also

* [Error Codes](/api/error-codes) - Complete list of error codes
* [JSON-RPC Types](/api/jsonrpc) - JSON-RPC type definitions