StreamableHttpMcpClient

This docs was updated at: 2026-02-23

com.paragon.mcp.StreamableHttpMcpClient  ·  Class

Extends McpClient

---

MCP client that communicates over HTTP with optional SSE streaming.

This client implements the Streamable HTTP transport as defined in the MCP specification. It supports:

• JSON responses for simple request-response patterns
• SSE streams for streaming responses
• Session management via MCP-Session-Id header
• Custom headers for authentication

Example Usage

var mcp = StreamableHttpMcpClient.builder()
    .serverUrl("https://mcp.example.com/api")
    .headerProvider(McpHeaderProvider.bearer(() -> authService.getToken()))
    .build();
mcp.connect();
var tools = mcp.asTools();

See Also

• McpClient
• McpHeaderProvider

Methods

builder

public static @NonNull Builder builder()

Creates a new builder for StreamableHttpMcpClient.

Returns

a new builder

---

connect

public void connect() throws McpException

Performs initialization handshake.

---

handleSseResponse

private @NonNull JsonRpcResponse handleSseResponse(@NonNull Response httpResponse)
      throws McpException

Parses SSE stream manually without external dependency.

SSE format: - Lines starting with "data:" contain the payload - Lines starting with "event:" contain the event type - Lines starting with "id:" contain the event ID - Empty lines separate events

---

getSessionId

public @Nullable String getSessionId()

Returns the current session ID.

Returns

the session ID, or null if not established

---

serverUrl

public @NonNull Builder serverUrl(@NonNull String serverUrl)

Sets the MCP server URL.

Parameters

Name	Description
serverUrl	the server URL

Returns

this builder

---

httpClient

public @NonNull Builder httpClient(@NonNull OkHttpClient httpClient)

Sets the OkHttpClient to use.

Parameters

Name	Description
httpClient	the HTTP client

Returns

this builder

---

headerProvider

public @NonNull Builder headerProvider(@NonNull McpHeaderProvider headerProvider)

Sets the header provider for custom headers.

Parameters

Name	Description
headerProvider	the header provider

Returns

this builder

---

connectTimeout

public @NonNull Builder connectTimeout(@NonNull Duration timeout)

Sets the connection timeout.

Parameters

Name	Description
timeout	the timeout duration

Returns

this builder

---

readTimeout

public @NonNull Builder readTimeout(@NonNull Duration timeout)

Sets the read timeout.

Parameters

Name	Description
timeout	the timeout duration

Returns

this builder

---

objectMapper

public @NonNull Builder objectMapper(@NonNull ObjectMapper objectMapper)

Sets the ObjectMapper for JSON serialization.

Parameters

Name	Description
objectMapper	the object mapper

Returns

this builder

---

build

public @NonNull StreamableHttpMcpClient build()

Builds the StreamableHttpMcpClient.

Returns

a new StreamableHttpMcpClient

Throws

Type	Condition
IllegalArgumentException	if serverUrl is not set