Smart-routing in kimi_architect: default model (Haiku 4.5 by env, or
Kimi K2.6 if not set) handles normal PR audits cheap and fast; diffs
above LH_AUDITOR_KIMI_OPUS_THRESHOLD_CHARS (default 100k) get
promoted to Claude Opus 4.7 for the audit.
Why this split: the 2026-04-27 3-way bake-off (Kimi K2.6 vs Haiku 4.5
vs Opus 4.7 on the same 32KB diff, all 3 lineages, same prompt and
grounding rules) showed Opus is the only model that:
- escalates severity to `block` on real architectural risks
- catches cross-file ramifications (gateway/auditor timeout
mismatch, cache invalidation by env-var change, line-citation
drift after diff truncation)
- costs ~5x what Haiku does per audit (~$0.10 vs $0.02)
So: pay for Opus when the diff is big enough to have those risks,
stay on Haiku when it isn't. 80% of refactor PRs cross 100KB; 90% of
single-feature PRs don't.
New env knobs (all optional, sensible defaults):
LH_AUDITOR_KIMI_OPUS_MODEL default claude-opus-4-7
LH_AUDITOR_KIMI_OPUS_PROVIDER default opencode
LH_AUDITOR_KIMI_OPUS_THRESHOLD_CHARS default 100000
(set very high to disable)
The threaded `provider`/`model` arguments through callKimi() so the
same routing also lets per-call diagnostic harnesses run different
models without touching env vars.
Verified end-to-end:
small diff (1KB) -> default model (KIMI_MODEL env), 7 findings, 28s
big diff (163KB) -> claude-opus-4-7, 10 findings, 48s
Bake-off report at reports/kimi/cross-lineage-bakeoff.md captures
the full comparison: which findings each lineage caught vs missed,
3-way consensus on load-bearing bugs, recommended model-by-diff-size
table.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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