Function exit_code_for 

pub fn exit_code_for(error: &Error) -> i32

Process exit code for an error returned by run — the CI contract.

0 success and 2 usage errors are clap’s, emitted before run is reached. 3 is reserved for a --require-fresh refusal so a pipeline can tell “the graph is stale” apart from “the query failed”; every other operational failure (missing artifact, bad Cypher, timeout, I/O) is 1.

The pip install codingest wheel’s _run_cli maps every error to PyRuntimeError, so a stale refusal exits 1 through the console script.