Finding
SymTrace, arXiv:2608.25920, submitted 2026-08-26, shows that whole-trajectory reruns confound causal repair with sampling luck. It records execution traces, establishes intervention anchors, reconstructs the exact prefix during replay, and regenerates only the downstream suffix. The originating team reports 67.97% failure reproduction and 6.90% repair for unguided reruns across three MAS frameworks. Symptom-driven anchored intervention repaired 20.15% of failures on the 536-trajectory SymFail dataset.
Evidence class: originating-team report with a human-annotated dataset, not yet independently reproduced by RuV.
Weighted Opportunity Score: 4.60/5.
RuV gap
Dream Machine already has deterministic witnesses, held-out promotion gates, trace-driven optimization work, and bounded mutation plans. Recuris experiment #36 localizes memory changes, but there is no reusable primitive that proves an experiment restarted from the same causal prefix before comparing a repair.
Without this invariant, a candidate can appear to repair a failure simply because the model resampled a different upstream trajectory.
Proposed primitive
Add AnchoredTraceReplay to @dream-machine/witness:
- canonicalize and hash the immutable trace prefix
- bind an intervention anchor to an event id and step
- verify a replay prefix before any downstream regeneration
- reject duplicate ids, non-monotonic steps, malformed anchors, prefix mutation, and suffix collisions
- produce a deterministic replay receipt containing prefix digest, anchor digest, regenerated suffix digest, and combined trace digest
The digest is evidence of trace identity, not execution authority.
MetaHarness roles
Use independent research, implementation, review, security, testing, reproducibility, and release roles. The reviewer and reproducibility roles must not share the implementation agent's generated repair rationale.
Benchmark
Compare under identical model, temperature, seeds, tool versions, task set, and evaluator:
- whole trajectory rerun
- anchored replay with no intervention
- anchored replay plus symptom-driven intervention
Report reproduction rate, repair rate, false-repair rate, wall time, tokens, API cost, prefix verification failures, variance, and per-failure-category results.
Security and falsification
Reject the primitive if replay can proceed after any prefix mutation, if regenerated events collide with immutable event ids, if the anchor can move without changing the receipt, or if apparent repair gains disappear after controlling the prefix.
Acceptance
The infrastructure implementation may land once deterministic tests and CI pass. Do not claim SymTrace-level repair gains until an independent matched reproduction shows at least 95% exact prefix verification, materially higher failure reproduction than whole reruns, no authority expansion, and zero acceptance of mutated prefixes.
Finding
SymTrace, arXiv:2608.25920, submitted 2026-08-26, shows that whole-trajectory reruns confound causal repair with sampling luck. It records execution traces, establishes intervention anchors, reconstructs the exact prefix during replay, and regenerates only the downstream suffix. The originating team reports 67.97% failure reproduction and 6.90% repair for unguided reruns across three MAS frameworks. Symptom-driven anchored intervention repaired 20.15% of failures on the 536-trajectory SymFail dataset.
Evidence class: originating-team report with a human-annotated dataset, not yet independently reproduced by RuV.
Weighted Opportunity Score: 4.60/5.
RuV gap
Dream Machine already has deterministic witnesses, held-out promotion gates, trace-driven optimization work, and bounded mutation plans. Recuris experiment #36 localizes memory changes, but there is no reusable primitive that proves an experiment restarted from the same causal prefix before comparing a repair.
Without this invariant, a candidate can appear to repair a failure simply because the model resampled a different upstream trajectory.
Proposed primitive
Add
AnchoredTraceReplayto@dream-machine/witness:The digest is evidence of trace identity, not execution authority.
MetaHarness roles
Use independent research, implementation, review, security, testing, reproducibility, and release roles. The reviewer and reproducibility roles must not share the implementation agent's generated repair rationale.
Benchmark
Compare under identical model, temperature, seeds, tool versions, task set, and evaluator:
Report reproduction rate, repair rate, false-repair rate, wall time, tokens, API cost, prefix verification failures, variance, and per-failure-category results.
Security and falsification
Reject the primitive if replay can proceed after any prefix mutation, if regenerated events collide with immutable event ids, if the anchor can move without changing the receipt, or if apparent repair gains disappear after controlling the prefix.
Acceptance
The infrastructure implementation may land once deterministic tests and CI pass. Do not claim SymTrace-level repair gains until an independent matched reproduction shows at least 95% exact prefix verification, materially higher failure reproduction than whole reruns, no authority expansion, and zero acceptance of mutated prefixes.