Constraint: roadmap-next-id.sh must preserve single-id stdout on success while failing closed if duplicate validation cannot run.
Rejected: Relying only on CI/pre-push duplicate checks | the helper is used immediately before appending and must not certify an already-poisoned file.
Confidence: high
Scope-risk: narrow
Directive: Keep roadmap-next-id.sh stdout machine-clean; route validation failures and checker availability errors to stderr, and keep focused helper behavior coverage in the docs/ROADMAP CI path.
Tested: scripts/roadmap-next-id.sh ROADMAP.md printed 725 before appending #725 and 726 after; temp ROADMAP with duplicate 999 exited nonzero and listed duplicate id; scripts/roadmap-check-ids.sh ROADMAP.md; bash -n scripts/roadmap-next-id.sh scripts/roadmap-check-ids.sh; python -m unittest discover -s tests -p test_roadmap_helpers.py; python -m pytest tests/test_roadmap_helpers.py -q; SKIP_CLAW_PRE_PUSH_BUILD=1 bash .github/hooks/pre-push
Not-tested: full cargo workspace build, unchanged docs/script-only path
Add a lightweight ROADMAP duplicate-id guard and wire it into the low-risk docs/pre-push paths so optimistic append collisions introduced after the next-id helper are caught before merge.
Constraint: Current ROADMAP contains legacy numbered lists and pre-helper duplicate low ids, so the default guard checks helper-era ids >=723 while preserving --min-id 1 for a future strict audit.
Rejected: Fail CI on every numeric duplicate in the whole historical ROADMAP | current main would fail before this PR because old prose/list numbering is already duplicated.
Confidence: high
Scope-risk: narrow
Directive: Keep roadmap-next-id.sh paired with roadmap-check-ids.sh when changing ROADMAP append workflows.
Tested: bash -n scripts/roadmap-check-ids.sh scripts/roadmap-next-id.sh .github/hooks/pre-push; scripts/roadmap-check-ids.sh; temp ROADMAP copy with duplicate 723 failed nonzero and listed id 723; SKIP_CLAW_PRE_PUSH_BUILD=1 .github/hooks/pre-push; git diff --check; python3 .github/scripts/check_doc_source_of_truth.py; python3 .github/scripts/check_release_readiness.py
Not-tested: full cargo workspace build/test because this is docs/scripts-only and the local pre-push cargo build was smoke-tested with its documented skip path.
