MCP error handling
JSON-RPC error codes and responses from the MCP server.
Error codes
The MCP server uses standard JSON-RPC 2.0 error codes:
- -32700: Parse error - Invalid JSON
- -32600: Invalid Request - Missing required fields
- -32601: Method not found - Unknown method name
- -32602: Invalid params - Malformed parameters
- -32001: Unauthorized or Insufficient scope
The -32001 error code covers both authentication failures and authorization issues. When you lack the required scope for a tool, the error includes details about what scope you need:
{
"jsonrpc": "2.0",
"id": 5,
"error": {
"code": -32001,
"message": "insufficient_scope",
"data": {
"tool": "add_application",
"granted_scopes": ["read:application"],
"required_scope": "write:application"
}
}
}
## Common Error Examples
Invalid JSON triggers a parse error:
```json
{
"jsonrpc": "2.0",
"id": null,
"error": {
"code": -32700,
"message": "Parse error",
"data": "unexpected character at position 12"
}
}
Unknown methods return method not found:
```json
{
"jsonrpc": "2.0",
"id": 8,
"error": {
"code": -32601,
"message": "Method not found",
"data": "Method 'unknown_method' not found"
}
}
## Additional Features
The MCP server implements the full JSON-RPC 2.0 specification including notifications (requests without an `id` field) and batch requests. The `ping` method provides a simple health check:
```json
{
"jsonrpc": "2.0",
"id": 9,
"method": "ping"
}
When running in demo mode, the server restricts write operations to protect the demonstration instance while allowing all read operations and authentication flows.How is this guide?