Decision (2026-05-05): KIMI_FUSION_MODEL=kimi-k2.6, FUSION_PROMPT_VARIANT=legacy.
This is what the live demo runs on, and what .env.example ships with.
Phase 4.1.F shipped a reproducible bench harness (scripts/phase4_bench.py) covering the full (model × prompt_variant) × clusters matrix. We chose not to spend hackathon-grade gateway budget on a live run because the decision is already settled by upstream evidence:
- Latency is no longer a model-selection criterion. The warm-caching strategy (see
TODO.md§ "Demo strategy — warm caching") collapses live demo wall-time to disk-read seconds regardless of cold-call latency. Selecting a faster model would buy nothing the cache does not already buy. - Quality wins, k2.6 stays the default. The empirical profile in
project_kimi_proxy_latency.md(auto-memory; informal Phase 4.1 measurements across 10+ live tests) showskimi-k2collapses Fusion latency to ~9 s but misses category-conflict detection, drops 1–2 attribute keys from the merged record, and parse-fails on ~33 % of identical prompts. None of those is acceptable against the Fusion contract documented inhackathon-brief.md. - No measurement has shown a strict-dominant alternative on quality to justify spending a bench cycle to confirm a foregone conclusion.
The bench harness is kept as-is for future re-decision; we just don't pay for it now.
Run the harness on five contrasted zones (Saint-Aignan, Orléans, Bordeaux, a coastal commune, a large-EPCI candidate):
uv run python scripts/phase4_bench.py orleans bordeaux saint-aignan sete lyon \
--models kimi-k2.6 kimi-k2 \
--variants legacy mechanical \
--clusters-per-zone 6CSV output lands in data/bench/fusion-<YYYYMMDD-HHMM>/. Read parse_ok, conflict-category coverage, INSEE precedence inversions, and merged-record key-count delta against the k2.6 baseline.
Switch only if a (model, variant) pair is strictly dominant on all four quality metrics defined for Phase 4.1.G:
parse_ok ≥ 95 %post-retry (so end-to-end ≥ 99 %).- 100 % conflict-category detection on cross-source clusters that carry one.
- 0 inversions of
INSEE > Wikidata > Atout-Franceprecedence on synthetic capacity fixtures. - Merged-record key-count parity with the k2.6 baseline within ±1 key.
A win on three of four is not enough — Fusion's contract is non-negotiable on conflict detection and on the precedence rule.