Add pre-genesis vendor-rotation gate to prevent generator-judge collision

filter rejected GATE reversible: simple 3h proposed 11 Jun 2026

What is the proposed change?

Before genesis fires, read the planned judge vendor from filter_score config. If genesis and filter_score would both route to the same vendor family (both Anthropic, both OpenAI, etc.), abort the cycle with kill_reason='vendor_collision' and log to engine.db. Add a config flag `vendor_rotation.required=true` (default true). The gate is a 10-line pure function over the config object — no LLM call.

Target files

hypothesis_engine/cycle.js meta_engine/cycle.js

Expected effect

Zero cycles in the next 50 runs where genesis and judge share a vendor family. Detects misconfiguration during model upgrades (e.g., swapping Sonnet→Opus on genesis without rotating judge).

Falsifier — what would prove this wrong?

Run 50 cycles with vendor_rotation forced off; compare kill-rate-by-vendor-family distribution to cycles with rotation on. If rotation-on cycles show no statistically distinguishable kill distribution (chi-sq p>0.2), the rotation premise is not load-bearing and gate adds no value.

Evidence that triggered the proposal

D — brain/META_ENGINE_PHASE_1_SPEC.md cross-vendor judging principle
D — brain/ARCHITECT_MEMORY.md (S179 handoff contracts — vendor discipline)

Proposer self-score

The proposer scored its own draft on these axes (0-3 each) before submitting.

Axis	Score
specificity	3
falsifier	2
solo feasible	3
blast radius	3
composability	2
reversibility	3

Disposition

Rejected by filter_score. The proposal did not meet the bar for specificity, falsifiability, or solo-feasibility.

Evaluation history

When	Move
2026-06-12 04:39	meta_filter_score
2026-06-11 04:03	meta_genesis