Issues

• API: Generalize client notification handlers for SDK client classes

  waiting for triage
  modelcontextprotocol/java-sdk#858 · Filter by author scottslewis opened on Mar 6, 2026

• Support application/json responses in Streamable HTTP transport (opt-in JSON response mode)

  enhancementP2
  Enhancement

  modelcontextprotocol/java-sdk#844 · Filter by author thiagomendes opened on Mar 4, 2026
  11

• Support parameter deserialisation to Java Objects using the MCPJsonMapper

  waiting for triage
  modelcontextprotocol/java-sdk#836 · Filter by author sdehors-ibm opened on Feb 25, 2026

• API: Generalize notifications for SDK server classes

  waiting for triage
  modelcontextprotocol/java-sdk#831 · Filter by author scottslewis opened on Feb 22, 2026

• Deprecate old docs and add references to the new docs

  documentationP2
  Task

  modelcontextprotocol/java-sdk#799 · Filter by author tzolov opened on Feb 16, 2026
  1

• Add conformance score in README

  documentationP2
  Task

  modelcontextprotocol/java-sdk#798 · Filter by author tzolov opened on Feb 16, 2026
  1

• Migrate the reference & APIs docs to the java-sdk project

  documentationP2
  Task

  modelcontextprotocol/java-sdk#796 · Filter by author tzolov opened on Feb 16, 2026

• Feature Request: Support for MCP Apps Extension (UI capabilities)

  enhancementwaiting for triage
  Enhancement

  modelcontextprotocol/java-sdk#780 · Filter by author jaguarliuu opened on Feb 12, 2026
  3

• Introduce a unified Virtual Threads friendly API

  enhancement
  Enhancement

  modelcontextprotocol/java-sdk#778 · Filter by author sdeleuze opened on Feb 10, 2026 · 4.x Planning
  1

• HttpClientStreamableHttpTransport: reconnect() called before status code check causes duplicate connections on 405

  waiting for user
  modelcontextprotocol/java-sdk#773 · Filter by author irwin-chequer opened on Feb 5, 2026
  2

• Missing @JsonIgnoreProperties(ignoreUnknown = true) on capability sub-records

  bugP1
  Bug

  modelcontextprotocol/java-sdk#766 · Filter by author maxisbey opened on Jan 29, 2026
  4

• MCP server in WAR on application server

  enhancementP3waiting for user
  Enhancement

  modelcontextprotocol/java-sdk#763 · Filter by author uhrm opened on Jan 29, 2026
  5

• StdioClientTransport: Inbound Scheduler and Error Scheduler threads are locked on Windows

  bugP2
  Bug

  modelcontextprotocol/java-sdk#759 · Filter by author ilsid opened on Jan 26, 2026
  1

• Add JPMS compatibility to Jackson JSON mapper

  bugP2
  Bug

  modelcontextprotocol/java-sdk#753 · Filter by author nknize opened on Jan 16, 2026

• I would like to maintain MCP server state persisted (sessionId)

  enhancementfeature/session-storageP2
  Enhancement

  modelcontextprotocol/java-sdk#738 · Filter by author poornimas-iyer opened on Dec 31, 2025
  2

• MCP server to be able to return custom http codes

  enhancementfeature/session-storage
  Enhancement

  modelcontextprotocol/java-sdk#737 · Filter by author poornimas-iyer opened on Dec 31, 2025
  1

• Add ability to intercept tool call executions.

  enhancementfeature/repositoriesP3
  Enhancement

  modelcontextprotocol/java-sdk#720 · Filter by author 24kpure opened on Dec 12, 2025
  8

• Allow custom or numeric request ID generation (Snowflake MCP server rejects string IDs)

  enhancementP3
  Enhancement

  modelcontextprotocol/java-sdk#703 · Filter by author manasnilorout opened on Nov 27, 2025
  1

• Allow disabling structuredContent duplication in McpAsyncServer

  enhancementP2
  Enhancement

  modelcontextprotocol/java-sdk#688 · Filter by author vdm24 opened on Nov 25, 2025
  3

• Java MCP Server examples are incomplete and non-runnable

  documentationP3
  Enhancement

  modelcontextprotocol/java-sdk#687 · Filter by author GVLLIFESTYLE opened on Nov 25, 2025
  3

• SDK rejects valid SSE comments, causing initialization timeout with Tavily MCP remote server

  bugP2
  Bug

  modelcontextprotocol/java-sdk#685 · Filter by author udayogra opened on Nov 20, 2025
  2

• Extract McpAsyncClient and McpSyncClient as an interface

  enhancementv2
  Enhancement

  modelcontextprotocol/java-sdk#680 · Filter by author He-Pin opened on Nov 19, 2025
  1

• SEP-1686: Tasks Support

  enhancementP1
  Enhancement

  modelcontextprotocol/java-sdk#668 · Filter by author He-Pin opened on Nov 15, 2025
  10

  

• There are two JsonSchemaValidator

  enhancementP3
  Enhancement

  modelcontextprotocol/java-sdk#666 · Filter by author He-Pin opened on Nov 15, 2025
  2

• Null fields in JsonSchema without @Nullable annotation break serialization with Jackson

  bugP3
  Bug

  modelcontextprotocol/java-sdk#664 · Filter by author stephanlensky opened on Nov 12, 2025