{"version":"2.1.288","anchor":"mcp-auto-backgrounded-call-feeds-a-host-check","canonical_anchor":"mcp-auto-backgrounded-call-feeds-a-host-check","heading":"Results of MCP tool calls moved to the background now go to a further check","tier":"internal","area":"MCP","scope":"individual","heads_up":false,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.288\/e\/mcp-auto-backgrounded-call-feeds-a-host-check","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.288","markdown":"### Results of MCP tool calls moved to the background now go to a further check\n\nWhen an MCP tool call is moved to the background automatically, its result text is now handed to another handler on some platforms, with a fallback if that fails\n\n**Unclear.** It is unclear what the handler does with the result text, which platforms it applies to, and what the fallback does.\n\n**What**\n\nMCP tools are extra tools that Claude Code can call from outside servers you connect it to. A call to one of these tools can be moved to the background automatically, so it keeps running while the session carries on. The handling of such a call has changed: on some platforms, Claude Code now passes the call's result text to a separate handler on the machine running Claude Code. If that handler fails, Claude Code falls back to another path.\n\n**Why**\n\nIn practice, results from MCP tool calls that run in the background may now be handled differently depending on the platform. What this extra step does with the result is not clear.\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 2\/5\n- Scope: individual\n- Heads-up: no"}