**Source URL:** https://limited.veevavault.dev/medical/mcp/vault-mcp-server/reference/errors

# Errors

The Vault MCP Server returns errors as either JSON-RPC errors for transport and protocol problems, or tool execution errors for failures inside an executing agent action.

## JSON-RPC Errors

JSON-RPC errors use the standard JSON-RPC 2.0 error object. The HTTP status code on the response indicates the specific condition.

| Code | Description |
| --- | --- |
| `-32700` | Parse error. Invalid JSON received by the server. |
| `-32600` | Invalid request. The JSON sent is not a valid JSON-RPC request object. |
| `-32601` | Method not found. The requested method is not supported. For example, `prompts/list` and `resources/list` are not supported by this server. |
| `-32602` | Invalid params. Invalid parameter name or missing required argument. |
| `-32000` | Server error. Returned for transport errors, authentication failures, invalid session IDs, and rate-limit responses. The HTTP status code on the response indicates which condition applied. |

## Tool Execution Errors

Tool execution errors occur when an agent action fails for a business logic reason, such as an invalid argument value or insufficient permission on a document. The server returns `HTTP 200 OK` and includes `isError: true` in the response payload. The error message appears in the `content` array.

```json
{
  "result": {
    "isError": true,
    "content": [{
      "type": "text",
      "text": "Error: Document 1001_1_3 not found, or you do not have permission to access it."
    }]
  }
}
```

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