JSON-RPC
JSON-RPC invokes a method on a JSON-RPC endpoint. The method and its parameters can be set here or overridden per call through the Input mapping.
The activity also handles streaming responses. Enable Streaming consumes Server-Sent Events and collects the streamed results, and Bridge To Workflow Stream additionally forwards those events to the caller as they arrive.
The activity has five tabs: Configuration, Headers, Auth, Input, and Output.
Configuration
| Field | Required | Description |
|---|---|---|
| Name | Optional | Name of the step, should be unique within this workflow. |
| Description | Optional | Describe the purpose or function of this step. |
| RPC Method | Optional | JSON-RPC method name. Available methods depend on the target server. |
| Endpoint URL | Optional | JSON-RPC endpoint URL. |
| Parameters | Optional | Request parameters as JSON. May be overridden through the input params. |
| Select Auth Context | Optional | Authorization context used to authenticate the request. |
| Timeout | Optional | Maximum time in milliseconds to wait for a response. Defaults to 15000. |
| Enable Streaming | Optional | Consume Server-Sent Events and collect streamed JSON-RPC results. |
| Bridge To Workflow Stream | Optional | Forward streamed events to the caller while also collecting them. |
RPC Method
The list offers methods common to agent and MCP servers: message/send, message/stream,
tasks/get, tasks/cancel, ping, initialize, tools/list, tools/call,
resources/list, resources/read, prompts/list, and prompts/get.
Which of these actually work depends on the target server.
Parameters
Supports named parameters as an object, or positional parameters as an array.
Timeout
If the server does not respond within Timeout, the request is terminated and marked as a timeout error. Increase it only for slower services or large payloads.
Headers
| Field | Required | Description |
|---|---|---|
| Headers | Optional | HTTP headers. |
Each row can be marked Request to send it, Response to capture it, and Required to enforce it.
Auth
| Field | Required | Description |
|---|---|---|
| Auth Type | Optional | No Auth or OAuth 2. |
| Auth Resource | Optional | OAuth resource containing credentials. |
Input
| Field | Data Type | Description |
|---|---|---|
| method | String | JSON-RPC method name to invoke. |
| params | Object or Array | JSON-RPC parameters. Supports named parameters as an object, or positional as an array. |
| headers | Object | HTTP headers sent with the request. Additional request headers defined in the configuration can be added. |
Values mapped here override the corresponding Configuration settings.
Output
The activity returns a jsonRpcResponse object, holding the result and any streamed events.
| Field | Data Type | Description |
|---|---|---|
| result | Object | Result of the JSON-RPC method call, present on success. |
| events | Object | Streamed events collected from the call. |