Rulings: each problem generation is its own visible dock job (the
extraction per-chunk pattern), and practice shares extraction's
semaphore — one process-wide 3-permit pool for ALL background LLM
jobs; total background LLM concurrency bounded at 3.
A. SHARED POOL: new src/agent/subagents/bg-llm-semaphore.ts —
globalThis __lhLlmSlots, PERMIT_COUNT 3 (the ruling), the
fresh-take/handed-off-permit deadlock discipline preserved for
BOTH callers. extraction.ts's withExtractSlot is now a thin
wrapper (job-row signal → withBgLlmSlot); __lhExtractSlots and
__lhPracticeSlots both die. The partitioner now acquires a permit
too (it's a background LLM job — it didn't before).
B. REGISTRY ROWS: the aggregate setId:generation / setId:grading rows
are replaced by setId:partition (phase partitioning, label
'Partitioning — title'), setId:gen:problemId (queued→generating,
'Problem i/N — title'), setId:grade:problemId (queued→grading,
'Grading i/N — title'). Each row carries its OWN abort controller
and its OWN usage (one PracticeStepLog per row — the aggregate
partitioner/generator/grader folding dies). Row key = feed id =
abort key (the dock dup-key law).
C. ABORT SEMANTICS: abortPracticeRow(key) routes by shape — gen row:
THAT problem only (error 'Aborted', siblings continue, set settles
ready with one errored problem); partition row: the whole run;
grade row: that grade drops (answer kept, re-submittable).
abortPractice(setId) composes from row aborts + the synchronous
persisted marks (a set-abort's verdict stands before the settles
re-read it — the settle step keeps an existing error status).
/api/activity/abort kind practice now takes the ROW key (charset
admits ':').
D. FEED + DOCK: ActivityPractice/FeedPractice carry per-row identity
(id = row key, problemIndex/problemTotal); dock blobs render per
row, labels carry the i/N; the aggregate row is gone.
E. Boot sweep unchanged at set grain; the live-row check is now a
key-prefix scan (any live row of the set protects it). The
updatedAt heartbeat covers the new row scheme as-is.
Tests (20 in the pipeline suite): per-problem row shape/uniqueness/
i-N labels (partition row frozen behind a gated partitioner; per-row
usage ISOLATION pin — b's log never shows on c's row); abort-one-gen
(sibling completes, set ready with one errored problem); partition-
row abort; queued grade-row abort (dead-ticket path: answer kept,
re-submittable, sibling lands); shared-pool identity + contention
(practice queues behind extraction-style holders); registry/dock
feed mapping. Test isolation hardened: unique per-store set ids,
afterEach registry/lock/pool reset (a timed-out test can no longer
poison the rest).
architecture.md: jobs-pattern paragraph rewritten (per-problem rows,
shared pool, abort routing).
1149/1149, tsc 0, lint 0, build 0.
amosblomqvist
88eb4b2ec0