{"version":"2.1.265","anchor":"new-sse-post-error-classifier-to-distinguish-real-failures-f","canonical_anchor":"new-sse-post-error-classifier-to-distinguish-real-failures-f","heading":"New SSE POST error classifier to distinguish real failures from benign JSON-RPC responses","tier":"internal","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.265\/e\/new-sse-post-error-classifier-to-distinguish-real-failures-f","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.265","markdown":"### New SSE POST error classifier to distinguish real failures from benign JSON-RPC responses\n\nClaude Code now tells apart real SSE connection failures from harmless error-looking responses\n\n**What**\n\nWhen posting to an MCP server's streaming endpoint (SSE, a way servers push data over an HTTP connection) fails with an HTTP 400, 404, or 405 status, Claude Code now looks inside the response body to check whether it's actually a harmless JSON-RPC response with a null ID, rather than a real connection failure.\n\n**Why**\n\nThis avoids treating a technically error-coded but benign server response as a genuine connection problem, which should cut down on false failure reports for some MCP servers.\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 1\/5"}