Head-to-head comparison
KAT Coder V2.5 Dev (Kwaipilot) and Laguna S 2.1 (Poolside) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.
Snapshot as of 19 September 2026
As of 19 September 2026, KAT Coder V2.5 Dev holds the stronger ModelCap Index position (#38 vs #41); and KAT Coder V2.5 Dev ships open weights.
Evidence: global-corpus-prior over 195 held-out anchors (22%); launch card against 2 resolved peers on 4 rows (78%); exceeds every named peer on 4 of 4 rows; optimism haircut 0 from cross-lab-probe; shrunk 3.7 toward the measured corpus · 5 reported rows against measured corpus ladders (72%); global-corpus-prior over 195 held-out anchors (28%); shrunk 4.8 toward the measured corpus. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.
Neither model has a published result on a public benchmark board ModelCap tracks yet.
Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.
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KAT Coder V2.5 Dev ranks higher on the ModelCap Index as of 19 September 2026: #38 against #41. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals overlap, so the rank difference alone does not establish a reliable capability advantage for your workload.
At least one of the two has no listed API price on ModelCap right now, so no price comparison is made.
Both publish a —-token context window.
The two models do not share a coding benchmark board on ModelCap yet, so no head-to-head coding score is published; the ModelCap Index position is the closest overall signal.
KAT Coder V2.5 Dev: Open weights. Laguna S 2.1: Restricted license. Open weights mean the checkpoint can be downloaded and self-hosted under its licence; API-only models are available solely through hosted endpoints.
ModelCap currently lists 0 API providers for KAT Coder V2.5 Dev and 1 for Laguna S 2.1, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.
Every figure comes from the sealed ModelCap dataset published 19 September 2026; the page re-renders within a minute of each data refresh, and the ModelCap Index positions are the same ones shown on the live rankings.