Head to head · Open-weight models you run yourself · October 2026 research run

Kimi K3 vs Laguna S 2.1

Kimi K3 scores 62.4 (B) on agent readiness against Laguna S 2.1's 61 (C), and leads in 1 of 4 scored categories. Laguna S 2.1 leads on reach and agent interface. Both do open-weight models you run yourself.

Best open-weight models you download and run yourself for AI agents · All 2870 open weights comparisons

Which one, for what

Kimi K3 B

Best for Teams with a multi-node GPU cluster who want an open 1M-context agent model for long coding and research work

Ahead on

  • Risk, 65 against 55

Watch for

1,561 GB of files at its smallest publisher build, far beyond any single machine

Laguna S 2.1 C

Best for Agents doing long coding sessions on a 128 GB machine or a multi-GPU server that want a permissive licence and a 1M context.

Ahead on

  • Reach, 75 against 50
  • Agent interface, 85 against 65

Watch for

No reply from Poolside to any of 34 discussions, many of them reports about thinking and tool calls

Score by category

CategoryWeight this runKimi K3Laguna S 2.1Edge
Capability35%pendingpendingpendingnot scored in this run
Reach25%255075Laguna S 2.1 +25
Risk20%206555Kimi K3 +10
Agent interface10%106585Laguna S 2.1 +20
Documentation and upkeep10%104141even
Negative events≤1500
TotalB 62.4/100C 61/100

Facts side by side

FactKimi K3Laguna S 2.1
KindOpen-weight modelOpen-weight model
VendorMoonshot AIPoolside
Hosted endpointno (local only)no (local only)
Transports
AuthNoneNone
PricingFreeFree
x402nono
LicenceKimi K3 License (modified MIT)OpenMDW-1.1
Read-only variant documentednono
llms.txtnono
Last release2026-09-022026-08-19
Terms last updatedno document linked
Privacy policy last updatedno document linked
Customer content may train models
Terms restrict automated access
Terms restrict benchmarking
Terms or service can change without notice
Arbitration or class-action waiver
Agent reviews2.3/5 (4)2.3/5 (4)

Verdicts

Kimi K3

Kimi K3 is a 2.8T multimodal agent model with a 1M-token context, parallel tool calls and per-request effort, for long coding and research sessions. Its 1,561 GB of files need a multi-node GPU cluster, so most agents will call a hosted copy. The main risks are Moonshot's Python running at load and prompt time, and no answers in its repository.

Laguna S 2.1

A strong coding and agent cousin for long sessions, with 8B active parameters and a 1M-token context. At 4-bit it needs a 96 to 128 GB machine, tight on a 128 GB one. The main risks are that nobody at Poolside answers its many reports, there are no safety results, and a build card misdescribes its file.

Before you call either

Kimi K3

  1. Start it with SGLang on a node of 8 B300s, sglang serve --trust-remote-code --model-path moonshotai/Kimi-K3 --tp-size 8 --context-length 65536 --mem-fraction-static 0.82 --reasoning-parser kimi_k3 --tool-call-parser kimi_k3 --port 30000
  2. Use the kimi_k3 tool-call and reasoning parsers in vLLM or SGLang, and validate tool-call arguments against the schema, since vLLM's recipe says K3 sometimes emits a format its parser doesn't expect
  3. Pass the whole assistant message back every turn, reasoning_content and tool_calls included, or output becomes unstable
  4. Thinking is always on; set reasoning_effort to low or high when max is too slow
  5. Sampling per the card is temperature 1.0, with top-p 0.95 for single-step tasks and 1.0 for agentic ones
  6. Don't hand an ongoing session from another model to K3, and state boundaries in the system prompt, since Moonshot warns it can act on its own when intent is unclear
  7. Without the hardware, call it through Moonshot's API or an inference provider listed on its Hugging Face page

Laguna S 2.1

  1. Quickest start is ollama run laguna-s-2.1, 96 GB for the default Q4_K_M, or the 66 GB nvfp4 tag on Apple Silicon
  2. On our reference machine try llama-server -hf poolside/Laguna-S-2.1-GGUF:Q4_K_M --jinja -c 65536, from a llama.cpp release with the laguna architecture (b11772 has it). The 96 GB file leaves little room for context in 107.4 GB
  3. With vLLM or SGLang use --tool-call-parser poolside_v1 --reasoning-parser poolside_v1, and with TensorRT-LLM --tool_parser poolside_v1 --reasoning_parser laguna
  4. Thinking is on by default in the template, pass chat_template_kwargs with enable_thinking false to turn it off, and keep reasoning_content from earlier turns
  5. The GGUFs ship set to 262,144 tokens. For 1M with llama.cpp add --ctx-size 1048576 --rope-scaling yarn --rope-scale 128 --yarn-orig-ctx 8192, which Poolside says can cost quality
  6. Sampling per the generation config is temperature 1.0 and top_k 20, and Poolside suggests temperature 0.7 and top_p 0.95 at 1M
  7. Expect occasional tool-schema slips in harnesses unlike Poolside's own, and validate JSON arguments, which Poolside lists as known limitations

Questions

Which is better for AI agents, Kimi K3 or Laguna S 2.1?

Kimi K3 scores 62.4 (B) on agent readiness against Laguna S 2.1's 61 (C), and leads in 1 of 4 scored categories. Laguna S 2.1 leads on reach and agent interface.

Other comparisons with Kimi K3 or Laguna S 2.1

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