Sibling standalone Cargo crate `harness/` under
experiments/2026-05-12-cross-model-authoring/ (out-of-workspace
idiom carried forward from cma.1 verbatim). Six modules:
strip_locations (regex pass for form-asymmetric location info,
calibrated against five real `ail check`/`ail parse` stderr
captures), pipeline (subprocess wrapper for parse|check|build +
5s-timeout exec; preflight on ail+clang), ionos (blocking reqwest
client + retry policy per spec), mock (canned-response loader),
scoring (CSV + summary.md), tasks (definition struct + loader).
main.rs ties them into the per-(cohort,task) loop with budget
accounting and per-turn artefact recording.
Four MVP tasks land with reference solutions that compile, build,
and execute green through the actual ail+clang pipeline:
t1_add_three (chained `+` + io/print_int), t2_length (polymorphic
List + recursion), t3_main_prints (minimal IO module), t4_count_zeros
(prelude Eq Int + branched if). Reference solutions stay in canonical
AILang form — param_modes is omitted when every parameter is the
Implicit default, consistent with the existing examples/ corpus.
13/13 tests green: 5 lib unit (strip_locations) + 5 integration
(strip_locations against verbatim captured fixtures) + 1
verify_references (drives every reference through the real
ail+clang pipeline) + 1 mock_full_run (full eight-row sweep with
mixed green-on-turn-2 + turn-limit cycles) + 1 budget_abort
(synthetic budget exhaustion with budget_abort rows + run_status).
Two implementer-phase repairs beyond the plan, both small and
surfaced in the iter journal Concerns:
1. pipeline.rs renames the program file to `<module-name>.ail.json`
between parse and check because `ail check` enforces filename
stem == module name (compiler contract the plan did not anticipate).
2. main.rs fills synthetic budget_abort rows for tasks the outer
loop never reached so scores.csv preserves the expected eight-row
shape on budget exhaustion.
One plan/text mismatch carried over: README "Total 8 passed" reflects
the plan's four-suite count; actual sweep produces 13. Doc-fix
candidate for cma.3.
cma.3 (live IONOS run + DESIGN.md addendum + roadmap edits) remains
out of scope.
Brummel
fe1fb6b4f0