{"version":"2.1.287","anchor":"headless-mcp-server-closes-sse-stream-on-abort-and-flags-ove","canonical_anchor":"headless-mcp-server-closes-sse-stream-on-abort-and-flags-ove","heading":"Claude Code's MCP server closes the stream when a client cancels a call","tier":"notice","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.287\/e\/headless-mcp-server-closes-sse-stream-on-abort-and-flags-ove","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.287","markdown":"### Claude Code's MCP server closes the stream when a client cancels a call\n\nWhen Claude Code acts as an MCP server and a client cancels a tool call, it now closes the open event stream\n\n**Unclear.** It is not clear whether the too-large result report can ever be triggered.\n\n**What**\n\nClaude Code can also act as an MCP server, offering its own tools to other programs. When a client cancels a tool call over streamable HTTP, Claude Code now closes the event stream it opened for that call.\n\nTool calls now also receive the client's authentication details and the request's ID. Code for reporting results that are too large has also been added.\n\n**Why**\n\nClients that cancel calls no longer leave a stream open.\n\n- Area: MCP\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 1\/5"}