fix(mcp): expose streamable HTTP resumable transport options

[guslegend0510]

Background

Fixes #2003.

When connecting to a Streamable HTTP MCP server that disables SSE and only accepts POST requests, tool calls can hang because AgentScope-Java does not expose the underlying MCP SDK transport options needed to disable resumable SSE-style startup behavior.

What Changed

• exposed resumableStreams(boolean) on McpClientBuilder for Streamable HTTP transport
• exposed openConnectionOnStartup(boolean) on McpClientBuilder for Streamable HTTP transport
• passed both options through to HttpClientStreamableHttpTransport.Builder
• added resumableStreams and openConnectionOnStartup support to tools.json MCP server config
• wired the new config fields through McpServerRegistrar

Example

Java API:

McpClientBuilder.create("test")
    .streamableHttpTransport(url)
    .resumableStreams(false)
    .openConnectionOnStartup(false)
    .buildSync();

Testing

mvn -pl "agentscope-core,agentscope-harness" spotless:apply
mvn -pl "agentscope-core,agentscope-harness" "-Dtest=McpClientBuilderTest,ToolsConfigLoaderTest" test

[codecov]

Codecov Report

❌ Patch coverage is 85.18519% with 4 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...tscope/harness/agent/tools/McpServerRegistrar.java	0.00%	4 Missing ⚠️

📢 Thoughts on this report? Let us know!

[zouyx]

LGTM

[chickenlj]

Do you think it reasonable if we disable SSE by default when streamable is enabled? Currently, user has to set resumableStreams and openConnectionOnStartup when streamableHttpTransport is used, which is a bit complexed I think.

Also, have you checked the latest MCP sdk release? I mean will it bring any behaviour changes if we upgrade to the latest version?