Coupled “mega-institution” dynamics — fork policy
This repository ships decoupled reference kernels (aggregate peg, network contagion, resource cascade, service backlog) and audit composites that evaluate the same shock schedule on multiple kernels without shared mutable state across World.step().
Why not here
A single coupled state graph (liquidity, overload, backlog, and network panic exchanging mass or signals inside one step()) is a different research product: new physics contracts, replay schema decisions, benchmark oracles, and attribution semantics. Shipping it inside this repo would blur the charter in BOUNDARIES.md and the non-goals in RESEARCH_FRONTIERS.md.
If you pursue it
Treat as a fork (or a clearly named sibling package):
1. New World (or orchestrator) module with an explicit coupling contract.
2. Schema bump for replay JSON (or a new top-level artifact) with migration notes and viewer guidance.
3. New golden benchmark bundles (same style as *_rollout_v1 in fragility_engine.benchmarks.suite); do not overload fragility-institutional-composite-v* JSON as if it were coupled physics.
4. Link back to this engine for schedule encoding, search, and counterfactual patterns where reuse is honest.
Related shipped tooling
Use institutional composite v1–v3 only for side-by-side metrics under identical schedules (scripts/institutional_composite_demo.py).
Public demo (when built)
On the GCE workbench (or after python scripts/build_public_site.py):
| Demo | URL |
|---|---|
| Coupled replay | /artifacts/replay_viewer/index.html#src=sample_coupled_institution_replay.json |
| Coupling mutation chain | /artifacts/attribution_viewer/index.html#src=sample_coupled_mutation_chain.json |
| Coupling strength sweep chart | /artifacts/coupling_sweep_viewer/index.html |
| Coupling baseline vs variant | /artifacts/coupling_comparison_viewer/index.html |
| Fork JSON bundle (download) | /artifacts/coupled_fork_demo/ |
| Policy (this page) | /docs/fork-coupling.html |
Regenerate fork artifacts and refresh the flagship certificate digests:
```bash
python scripts/regenerate_coupled_fork_artifacts.py
python scripts/narrate_coupled_fork_bundle.py --cite-digest
```