Function write_specimen 

pub fn write_specimen(
    repo: &Path,
    merge: &str,
    outcomes: &[Result<DifferentialOutcome, String>],
    state_dir: &Path,
) -> Result<PathBuf, String>

Packages a flagged merge and its reproduction runs as a corpus specimen under state_dir/specimens/<merge>.json (D27).

The specimen is metadata, not evidence: the observation rows it points at (by id) stay in the ledger, and the JSON records how often the interaction failure reproduced so a reader can tell a 6/6 conflict from a 1/6 flake without replaying anything. Nothing is published; the file lives in the operator’s state directory.

Errors

The merge cannot be resolved to two parents, or the specimen file cannot be written.