Session 19

Session 19 (2026-02-24)¶

Capture: /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst
Capture SHA256: fd151c5e063ea3b1419643a1df3fa6439b523fde3a082fc93b51038b93a4fabe
Baseline verifier command: uv run crimson original divergence-report /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --float-abs-tol 1e-3 --window 24 --lead-lookback 1024 --run-summary-short --run-summary-focus-context --run-summary-focus-before 8 --run-summary-focus-after 4 --run-summary-short-max-rows 30 --json-out analysis/frida/reports/session19/quest_1_8_baseline_nocache.json --no-cache
First mismatch progression:
baseline: tick 75 (rng_stream_mismatch; rng.tail_shortfall; missing_tail=1)
bisect: first_bad_tick=75 (rng_stream_mismatch)

This capture did not clear; both baseline and bisect agree on a very early RNG frontier (tick 75).
Focus trace at tick 75 confirms a one-draw native tail shortfall:
capture_calls=81, rewrite_calls=80, prefix_match=80, missing_native_tail=1
missing native caller id is 0x0043d4bd (currently unmapped in focus output).
Rewrite RNG callsite distribution at the focus tick is dominated by blood/decal paths:
src/crimson/effects.py:add_random (x48 across lines 498..501)
src/crimson/effects.py:spawn_blood_splatter (x20 across lines 790..799)
src/crimson/sim/presentation_step.py:queue_projectile_decals_post_hit (x3)
Divergence-report lead attribution is consistent with a missing RNG-consuming branch around projectile-hit/death FX on this early kill event.

uv run crimson original capture-health /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst
result=ok (loader/telemetry gate passed; ticks_total=992).
uv run crimson original divergence-report /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --float-abs-tol 1e-3 --window 24 --lead-lookback 1024 --run-summary-short --run-summary-focus-context --run-summary-focus-before 8 --run-summary-focus-after 4 --run-summary-short-max-rows 30 --json-out analysis/frida/reports/session19/quest_1_8_baseline_nocache.json --no-cache
result=diverged kind=rng_stream_mismatch tick=75.
uv run crimson original bisect-divergence /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --window-before 12 --window-after 6 --json-out analysis/frida/reports/session19/quest_1_8_bisect_nocache.json --no-cache
result=diverged first_bad_tick=75 kind=rng_stream_mismatch.
uv run crimson original focus-trace /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --tick 75 --near-miss-threshold 0.35 --top-rng 10 --near-miss-limit 8 --diff-limit 8 --no-cache --json-out analysis/frida/reports/session19/quest_1_8_focus_75_nocache.json
missing_native_tail=1 at caller 0x0043d4bd.

Session 19 started because the capture did not clear.
Next probe should map caller 0x0043d4bd to a concrete native path and reconcile the missing single RNG draw before/inside the early projectile-hit death FX branch.

First mismatch progression (after fixes):
tick 75 (rng_stream_mismatch; missing_tail=1)
tick 188 (rng_stream_mismatch; value-stream; pre-focus tick 187 had +78 rewrite tail draws)
tick 300 (state_mismatch: creature_count + perk.choices ordering skew)
cleared: result=ok (no divergence in search range)

Native caller 0x0043d4bd resolves to sfx_play_exclusive path and consumes one RNG draw when first-hit game tune triggers.
Remaining tick 188 RNG drift came from creature slot-32 heading branch skew near tau boundary in angle_approach; this produced an extra projectile hit at tick 187 and consumed extra decal/blood RNG.
tick 300 non-RNG mismatch was ordering-only:
capture consumed quest spawn RNG before perk menu RNG on that tick,
replay event partition was running deferred PerkMenuOpenEvent before deferred capture spawn hooks.

src/crimson/sim/presentation_step.py
consumed one RNG draw on first-hit game-tune trigger (native sfx_play_exclusive parity).
src/crimson/sim/sessions.py
added persistent game_tune_started state to QuestDeterministicSession and threaded it into StepPipelineOptions.
src/crimson/modes/quest_mode.py
stopped hardcoding game_tune_started=False; now uses session state.
src/crimson/modes/replay_playback_mode.py
mirrored quest replay path to use session game_tune_started.
src/crimson/creatures/runtime.py
tightened _angle_approach to native-like float32 spill behavior on intermediates/returns.
src/crimson/sim/driver/replay_events.py
in deferred original-capture partitioning, now orders post-step events as: state_transition -> capture_spawn -> perk_menu_open.
Tests:
tests/test_presentation_step.py
tests/test_death_timing.py
tests/test_creature_runtime.py
tests/test_replay_perk_menu_open_event.py

uv run pytest tests/test_creature_runtime.py tests/test_presentation_step.py tests/test_death_timing.py tests/test_quest_deterministic_session.py tests/test_replay_playback_mode_audio.py tests/test_replay_playback_mode_timing.py tests/test_quest_mode_spawns.py
80 passed.
uv run pytest tests/test_replay_perk_menu_open_event.py tests/test_replay_runners_quest.py
20 passed.
uv run crimson original divergence-report /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --float-abs-tol 1e-3 --window 24 --lead-lookback 1024 --run-summary-short --run-summary-focus-context --run-summary-focus-before 8 --run-summary-focus-after 4 --run-summary-short-max-rows 30 --json-out analysis/frida/reports/session19/quest_1_8_after_rngfix3_baseline_nocache.json --no-cache
result=ok.
uv run crimson original bisect-divergence /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --window-before 12 --window-after 6 --json-out analysis/frida/reports/session19/quest_1_8_after_rngfix3_bisect_nocache.json --no-cache
result=ok.
uv run crimson original verify-capture /Users/banteg/syncthing/frida/gameplay_diff_capture.quest_1_8.msgpack.zst --float-abs-tol 1e-3 --max-field-diffs 32
ok: 992 checkpoints match.

quest_1_8 now clears end-to-end on this branch.
Next recapture can proceed; Session 19 remains the capture-clear record for SHA fd151c5e063ea3b1419643a1df3fa6439b523fde3a082fc93b51038b93a4fabe.