Day 1 brief · July 21, 2026

Laguna S 2.1: open weights that punch above their size

Poolside shipped Laguna S 2.1 today: a 118B MoE (8B active) coding model that sits next to models several times its size on Terminal-Bench 2.1. Here’s where it actually lands against open peers and the closed frontier, and what that means if you care about running serious agentic coding on a desk machine.

Released: 2026-07-21 License: OpenMDW-1.1 Focus: benchmarks, not tok/s Sibling: Laguna XS 2.1 (July 2)

1. What shipped today

Laguna S 2.1 is Poolside’s scale-up from Laguna XS 2.1 (released July 2). Same product family, different weight class: S is the “serious local agent” box; XS is the “fits a normal Mac” box.

Total / active

118B / 8B

MoE · per token

Terminal-Bench 2.1

70.2%

thinking on · pool harness

Context

1M

thinking + no-thinking

License

OpenMDW

1.1 · weights public

Open weights Agentic coding Terminal agents SWE / DeepSWE Local + API NVFP4 / quant path

Who it’s for

  • Local / private agentic coding loops
  • Desktop-class GPUs (not phone RAM)
  • People who want open weights under a permissive model license

Who it’s not for

  • Replacing Sol / Fable on the hardest multi-day tasks
  • Ultra-light laptops that barely run XS
  • Blind leaderboard chasing without a harness
“Laguna S 2.1 is, as far as we can measure, the most capable agentic coding model in its weight class… On Terminal-Bench 2.1 it scores 70.2, sitting beside models 5–25× its size and ahead of several of them.” — @poolsideai, launch day

2. Terminal-Bench 2.1 vs parameter count

This is the chart that matters for the release story. Scores below are Terminal-Bench 2.1 pass@1 as compiled in Poolside’s launch materials (max of vendor / official leaderboard / third-party, as of July 21, 2026). Closed models with undisclosed size are listed with “—” for params.

GPT-5.6 Sol
88.8
Kimi K3
88.3
Claude Fable 5
88.0
GPT-5.6 Terra
87.4
GPT-5.6 Luna
84.7
Qwen 3.7 Max
74.5
Hy3 295B
71.7
Laguna S 2.1
70.2
DeepSeek V4 Pro
64.0
Nemotron 3 Ultra
56.4
Laguna XS 2.1
33.4

Bar scale = absolute % score (not relative). Frontier rows are closed / API tier.

# Model Total Active TB 2.1 Type
1 GPT-5.6 Sol 88.8% Closed
2 Kimi K3 2.8T 50B 88.3% Open weights
3 Claude Fable 5 88.0% Closed
4 GPT-5.6 Terra 87.4% Closed
5 GPT-5.6 Luna 84.7% Closed
6 Claude Opus 4.8 84.6% Closed
7 Claude Sonnet 5 80.4% Closed
8 Muse Spark 1.1 80.0% Closed / undisclosed
9 Qwen 3.7 Max 74.5% API / undisclosed size
10 Tencent Hy3 295B 21B 71.7% Open weights
11 Laguna S 2.1 118B 8B 70.2% Open weights
12 MiniMax M3 428B 23B 66.0% Open weights
13 DeepSeek-V4-Pro-Max 1.6T 49B 64.0% Open weights
14 Inkling 975B 41B 63.8% Open weights
15 DeepSeek-V4-Flash-Max 284B 13B 61.8% Open weights
16 Nemotron 3 Ultra 550B 55B 56.4% Open weights
18 Qwen3.6-27B 27B 51.3% Open weights
19 Qwen3.6-35B-A3B 35B 3B 44.9% Open weights
20 Nemotron 3 Super 120B 12B 38.6% Open weights
21 Laguna XS 2.1 33B 3B 33.4% Open weights
22 Mistral Small 4 119B 21.4% Open weights

Source: Poolside “Introducing Laguna S 2.1” (2026-07-21). Rank numbers follow their published TB 2.1 table. “Active” is MoE activated params per token when disclosed.

Efficiency read (the point of the release)

3. Other coding benchmarks (same release table)

Terminal-Bench is the launch headline. These additional agentic / software engineering numbers show where S 2.1 is strong vs where frontier still owns the board.

Model Size SWE Multi SWE Pro DeepSWE SWE Atlas Toolathlon
Laguna S 2.1 118B-A8B 78.5% 59.4% 40.4% 46.2% 49.7%
Tencent Hy3 295B-A21B 75.8% 57.9%
DeepSeek-V4-Pro-Max 1.6T-A49B 76.2% 55.4% 9.0% 27.2% 55.9%
Inkling 975B-A41B 54.3% 45.5%
Nemotron 3 Ultra 550B-A55B 67.7% 34.3%
Qwen 3.7 Max 78.3% 60.6%
Muse Spark 1.1 61.5% 53.3% 42.2% 75.6%
Claude Fable 5 80.3% 70.0%
Kimi K3 2.8T-A50B 69.0%
GPT-5.6 Sol 73.0%
GPT-5.6 Terra 70.0%
GPT-5.6 Luna 67.2%

Poolside table, 2026-07-21. Laguna scores in pool harness with thinking; peers are max public reported scores. Dashes = not reported in that table.

DeepSWE is the honesty check. Frontier models cluster high 60s–70s. S 2.1 at 40.4% is not Fable-class, but it crushes DeepSeek-V4-Pro-Max’s 9.0% at 1.6T in the same snapshot — another efficiency signal, not a claim of absolute SOTA.

4. Laguna XS 2.1: the smaller sibling (July 2)

If your constraint is “runs on a normal Mac / one consumer GPU,” look at XS 2.1 (33B total / 3B active), not S. Different weight class, different expectations. Poolside’s XS card used Terminal-Bench 2.0 (not 2.1) with their agent harness — do not mix those columns with the TB 2.1 table above without a note.

Model Size SWE Verified SWE Multi SWE Pro TB 2.0
Laguna XS 2.1 33B-A3B 70.9% 63.1% 47.6% 37.5%
Laguna XS.2 33B-A3B 69.9% 57.7% 46.3% 35.7%
Qwen3.6-35B-A3B 35B-A3B 73.4% 67.2% 49.5% 51.5%
North Mini Code 30B-A3B 67.6% 40.2% 36.0%
MAI-Code-1-Flash 137B-A5B 71.6% 65.5% 51.2% 54.8%
gpt-oss-120B 120B-A5B 16.2% 18.7%
Claude Haiku 4.5 73.3% 39.5% 29.8%
GPT-5.4 Nano 52.4% 46.3%

Source: Hugging Face card for poolside/Laguna-XS-2.1 (benchmarks as of ~July 2, 2026). On the separate TB 2.1 leaderboard table, XS 2.1 is listed at 33.4% — different suite / compilation.

“Doesn't seem to be at Qwen 3.6 on benchmarks but looks like a competitive US based model.” — r/LocalLLaMA on XS 2.1

5. What this means (day 1 take)

1. Efficiency is the product

S 2.1’s story is not “we beat Sol.” It’s “we put 70% Terminal-Bench-class agentic coding into a weight class you can actually host.” That matters for privacy, air-gapped shops, cost at high volume, and people who refuse to ship their entire repo to a frontier API.

2. The frontier is still the frontier

GPT-5.6 Sol / Terra / Luna and Claude Fable 5 (plus Kimi K3 at 2.8T) still own the top of Terminal-Bench and especially DeepSWE. If your job is hardest-path, multi-day agentic work and budget is not the constraint, rent the frontier.

3. Open weights re-clustered

In the disclosed-size open band, S 2.1 sits in a sweet spot: above DeepSeek V4 Pro Max and Nemotron 3 Ultra on TB 2.1 despite far fewer total parameters; within shouting distance of Hy3; far above same-size dense/open peers like Mistral Small 4. Qwen remains the naming gravity well for local builders (especially at 27B–35B), but S changes the “US open coding model” conversation on day one.

4. Pick S vs XS by machine, not by FOMO

Choose XS 2.1 if…

  • ~36GB unified / single consumer GPU
  • You want Mac-class local agents
  • You’re fine near Qwen3.6-35B territory, not Fable

Choose S 2.1 if…

  • Desktop / workstation / DGX Spark class
  • You want open weights near the 70% TB band
  • You care about MoE 8B active efficiency
“One of two: benchmaxed AF or we have a new efficiency king.” — r/LocalLLaMA, launch day reaction to S 2.1

6. Caveats (read these)

Harnesses move numbers. Terminal-Bench scores vary a lot with agent stack (Codex CLI vs Terminus vs custom). Poolside reports Laguna in pool with thinking; peers are often “best published.” Treat rankings as directional, not courtroom evidence. Poolside is publishing full evaluation trajectories at trajectories.poolside.ai — use them if you need to audit.

7. Sources

Research notes from a multi-source pass also live at:

~/Documents/Last30Days/laguna-xs-2-1-poolside-raw-v3.md