Instruction file imported from flext-sh/flext-tests (.cursor/rules/runtime--causal-subprocess.mdc). Copyright stays with the author.

Child-process failures remain causal

Validate the executable, arguments, environment, working directory, ownership, timeout contract, and expected publications before spawning. A child nonzero exit, timeout, signal, spawn failure, malformed output, or incomplete publication terminates the workflow with the native failure and captured causal evidence.

Do not use unchecked execution, shell error masking, || true, exit-code remapping, timeout-to-skip conversion, output heuristics, retries, alternate commands, or success based on partial output. Cleanup may terminate only the process group created and owned by this invocation; the original child failure remains the exception re-raised.

See also: strict-execution.md (rule file) — aggregate parent policy.