title: The config file is optional and read when present status: active origin: kind: agent recorded_at: '2026-10-29T17:52:32.604Z' id: SCEN-the-config-file-is-optional-and-read-when-present type: scenario --- Given the example project without mutalog.config.pl, when the user lists with --mutate, then all 55 mutants are found; when a config naming only arith is added, then only the 2 arith mutants are listed.

Context

Checked end to end by e2e:config_file_is_optional_and_read, which runs Mutalog as a separate process.