# SIM2B / SIM3B Practical Policy Scope

Status:

```text
SIM_SERIES_PRACTICAL_CLOSURE_MIXED__REAL_SIMULATION_PILOT_NOT_READY__NO_PHYSICAL_CLAIM
```

SIM2B/SIM3B are follow-up scope tests after the first SIM2/SIM3 boundaries.
They do not erase the SIM2/SIM3 mixed results.

## Why SIM2B/SIM3B Were Added

SIM2 showed that event-only checkpointing loses to uniform-time checkpointing
for smooth interpolation. SIM2B tested a more practical coverage-plus-event
checkpoint rule.

SIM3 showed that a record-heavy detail policy is not a broad compression rule.
SIM3B tested a hybrid source/gradient/delta detail rule.

## Result

Raw outputs:

```text
experiments/218_sim2b_sim3b_practical_policy_scope/raw/sim2b_sim3b_practical_policy_scope_2026-06-23/
```

| Layer | Status | Counted Passes | Practical Reading |
| --- | --- | ---: | --- |
| SIM2B | `SIM2B_COVERAGE_EVENT_CHECKPOINT_MIXED__FINITE_STORAGE_BUDGET_SCOPE_BOUNDARY__NO_PHYSICAL_CLAIM` | 0/3 | Even coverage-plus-event checkpointing loses to uniform-time baseline. |
| SIM3B | `SIM3B_HYBRID_DETAIL_COMPRESSION_MIXED__FINITE_DETAIL_BUDGET_SCOPE_BOUNDARY__NO_PHYSICAL_CLAIM` | 2/3 | Hybrid detail compression is a scoped candidate but not broad enough. |

## Interpretation

SIM2B creates a clear product rule:

```text
Do not use ITHKOR-SIM checkpoint placement yet. Use uniform or domain-native
checkpointing until a stronger checkpoint objective is defined.
```

SIM3B creates a softer product rule:

```text
Hybrid detail compression is promising for some structured worlds, but not
ready as a default compression policy.
```

## Boundary

No QPU was submitted. No physical claim is added. This is a practical
engineering scope result only.