{"version":"2.1.246","anchor":"stdio-mcp-servers-start-through-a-shared-launch-helper-that-","canonical_anchor":"stdio-mcp-servers-start-through-a-shared-launch-helper-that-","heading":"Stdio MCP servers start through a shared launch helper that can defer or cap them","tier":"internal","area":"MCP","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.246\/e\/stdio-mcp-servers-start-through-a-shared-launch-helper-that-","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.246","markdown":"### Stdio MCP servers start through a shared launch helper that can defer or cap them\n\nStdio MCP servers now launch through a shared helper that can rewrite, defer or cap them.\n\n**What**\n\nThe command and arguments for a stdio MCP server are no longer handed straight to the connection; they pass through a helper tagged `mcp` that can rewrite them and reports back whether the launch was deferred or capped. A per-server exemption bypasses the helper entirely.\n\n**Details**\n\n- The helper returns `pending` and `capped` flags, both false in the ordinary case.\n- On a successful connection the server's process id gets extra bookkeeping when the launch was pending or capped, on top of the existing registration.\n- Whether the helper defers the launch or wraps the command in a placement prefix is not determinable from the shipped code.\n\n**Evidence**\n\n`pending: !1, capped: !1`\n\n- Area: MCP\n- Tier: Under the hood\n- Useful: 2\/5\n- Signal: 3\/5"}