{"name":"UV_THREADPOOL_SIZE","slug":"uv-threadpool-size","family":"env","title":"Environment variables","noun":"environment variable","description":"When Claude Code initializes an HTTP transport to an MCP server, it writes an `Environment:` log line for that server that includes `UV_THREADPOOL_SIZE` (shown as `default` when unset or empty), next to `NODE_OPTIONS` and the proxy variables. Claude Code does not otherwise read it.","description_source":"code","described_by":{"bundle":"2.1.286","author":"claude-opus-5-5"},"presence":{"first_seen":"2.1.138","removed_in":null,"in_current_build":true,"newest_mined":"2.1.308","builds":149,"mined_builds":149,"first_cited":null},"aliases":[],"entries":[],"entries_total":0,"docs":[],"docs_total":0,"gates":[],"related":[],"url":"https:\/\/changelogs.core-directive.com\/reference\/env\/uv-threadpool-size","family_url":"https:\/\/changelogs.core-directive.com\/reference\/env.json"}