# Engine worker checkpoint

Updated: 2026-09-09

## Followup checkpoint (openai/gpt-5.6-terra)

- Source worktree: `/home/alex/sots-engine` at `7741d42fc5e4e761e6449bdaf0e4a61d00036a23`;
  RE state root: `/home/alex/sots-re` at `3bfde5a70d874a723e797a695bbd847fd82c0aa7`.
- Preserved command-replay leaf writes during `RunStrategicTurn`'s final record fold, then added
  an `app_command_replay` regression that verifies an applied replay write changes the board and
  is included exactly once beyond all phase records.
- Changed configured empty save directories from skips to failures in the modified app turn,
  app turn-record, design census, Mars save, and Mars domain corpus consumers. Unset dependencies
  retain their existing skip behavior; unreadable and parse-error saves remain failures without
  skip wording.
- Observation: `git diff --check` passed before focused build/test execution. Existing unrelated
  rollout changes are present in the engine worktree and were left untouched.
- `mars_stream_test_save` now stops after reporting parser errors, before accessing typed-shape
  assumptions. `mars_stream_domains` reports parse/read errors and omits those saves from its
  domain archive. This turned the malformed-save signal termination into ordinary nonzero test
  failures; it is a test-boundary fix within the assigned contract, not an architecture change.
- Results: fresh `/tmp/opencode/sots-engine-followup` host build succeeded. With
  `SOTS_SAVES_DIR=/home/alex/sots-re/verify/results/saves`, `ctest --test-dir
  /tmp/opencode/sots-engine-followup --output-on-failure -R
  '^(app_command_replay|app_turn|app_turn_record|mars_stream_save|mars_stream_domains)$'`
  passed 5/5 twice, after the final test-boundary change.
- Negative evidence: each modified corpus executable returned nonzero for the configured empty
  directory `/tmp/opencode/sots-empty-corpus`: app turn, app turn-record, Mars save, Mars
  domains, and design census (the census was given `SOTS_DATA_DIR=/tmp/opencode`). Each of the
  four applicable consumers returned a normal nonzero failure for configured malformed
  `/tmp/opencode/sots-invalid-corpus/malformed.sav`; no skip wording or signal termination.
- Skip evidence: `env -u SOTS_SAVES_DIR -u SOTS_DATA_DIR ctest --test-dir
  /tmp/opencode/sots-engine-followup --output-on-failure -R
  '^(app_turn|app_turn_record|mars_stream_save|mars_stream_domains|game_design_census)$'`
  reported all five as CTest skipped. Only unset dependencies take that path.
- `git diff --check` passed after the final edits. No broad gate was run. Existing unrelated
  rollout changes in both worktrees remain untouched.
- Completion: followup contract implemented and focused evidence recorded. Next action: stop;
  lead may consume this checkpoint for the coordinated source-stable gate.

- Implemented nonserialized `MT19937::words_drawn()` accounting. It resets on `seed()` and
  successful `load_state()` and is not included in save serialization.
- `CountingRandom` now measures bounded-integer rejection consumption from that monotone count,
  so a rejection loop may cross any number of twists.
- Removed S13 wrapper aggregation of P01..P12 counters; appended player records are the only
  contributors to final turn totals.
- Added MT boundary/rejection and reset/load tests, plus an app corpus test that validates
  reported RNG words against the independently persisted generator post-state.
- Corpus absence now returns 77 for app/census tests; unreadable or parse-error saves fail and
  nonzero executed saves remain required. CTest skip properties were added to dependency tests.
- Verification: fresh build at `/tmp/opencode/sots-engine-accounting` configured and built
  successfully. `SOTS_SAVES_DIR=/home/alex/sots-re/verify/results/saves ctest --output-on-failure`
  passed 52 of 59 tests; the remaining 7 were reported by CTest as skipped.
- Skip inventory verified with verbose CTest: `game_config_replay` lacks `SOTS_M1_TRACE` and
  `SOTS_DATA_DIR`; `game_data_realdata`, `game_design_realdata`, and `mars_text_realdata` lack
  data inputs; `game_design_census` lacks `SOTS_DATA_DIR`; `game_sim_smoke_real_save` lacks
  `SOTS_SAVES_JSON`; `mars_vfs_realdata` lacks `SOTS_GOB_DIR`. No configured corpus failure was
  skipped: `app_turn`, `app_turn_record`, `mars_stream_save`, and `mars_stream_domains` executed
  against the required saves directory and passed.
- Focused rerun passed `mars_rng_unit`, `app_turn`, and `app_turn_record`; `game_design_census`
  was CTest-skipped for its missing data-root dependency. `git diff --check` is clean.
- Limitation: full asset-dependent acceptance remains unavailable locally because the listed asset
  and trace paths are unset. The configure cache does not consume `-DSOTS_SAVES_DIR`; the required
  path was supplied to CTest through its runtime environment.