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Head to head · Decision models · October 2026 research run

Liquid d1 vs Drex 1.5

Drex 1.5 scores 69.7 (B) on agent readiness against Liquid d1's 43.5 (E), and leads in every scored category. Both do decision models.

Best decision models for AI agents · All 91 decisions comparisons

Liquid d1Liquid AI · Model API E43.5/100#886 of 954 Drex 1.5Nace AI, Inc. (Nace.AI) · Model API B69.7/100#172 of 954

Which one, for what

Liquid d1 E

Best for Classification, routing, yes or no gates and rubric scoring over text and images at a low per-token price, or on your own hardware with d1-3B where data can't leave.

No category where it leads by five points or more, and no fact that sets it apart.

Watch for

The terms of 30 September 2026 allow Liquid to train on API content, with no opt-out or zero-retention option found

Drex 1.5 B

Best for Routing, triage and yes or no gates inside an agent, where the caller supplies the options and acts on the probabilities. Suited to hosted use at a low per-token price, or to open weights where the licence fits.

Ahead on

  • Reliability, 80 against 21
  • Schema & documentation, 88 against 59
  • Agent ergonomics, 85 against 63
  • Security & auth, 65 against 35
  • Payments & pricing, 40 against 27
  • Maintenance & community, 65 against 60
  • Transparency & trust, 63 against 54

Watch for

The rank 1 claim comes from Nace's own run on Decision Index 0.3.1, and Drex is not on the public board for 0.3 or 0.2.1.

Score by category

CategoryWeight this runLiquid d1Drex 1.5Edge
Reliability16%202180Drex 1.5 +59
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.25988Drex 1.5 +29
Agent ergonomics13%16.26385Drex 1.5 +22
Security & auth14%17.53565Drex 1.5 +30
Payments & pricing10%12.52740Drex 1.5 +13
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86065Drex 1.5 +5
Transparency & trust7%8.85463Drex 1.5 +9
Negative events≤150-2
TotalE 43.5/100B 69.7/100

Facts side by side

FactLiquid d1Drex 1.5
KindModel APIModel API
VendorLiquid AINace AI, Inc. (Nace.AI)
Hosted endpointhttps://api.liquid.ai/decisions/v1/systemonehttps://console.nace.ai/v1/systemone
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingFreemiumFreemium
x402nono
LicenceThe hosted d1 model is proprietary under Liquid AI's terms of service. The d1-3B and d1-omni-600M weights and model code are under the LFM Open Licence v1.0, which is based on Apache-2.0 and conditions commercial use on annual revenue under $10 million. Training code and data aren't publishedHosted API under the Nace AI Terms of Service, last updated 5 May 2026. Weights under the Nace AI Open RAIL-M licence (modified, version 1.0, October 2026), which is not an open-source licence. Businesses above $1 million in revenue or funding need a separate commercial licence, and competing products are excluded. The bundled code/kev package, derived from Jared Palmer's Kev (https://github.com/jaredpalmer/kev), and the GitHub repository are Apache-2.0, and the agent skill is MIT.
Read-only variant documentednono
llms.txtyesyes
Last release2026-10-072026-09-28
Terms last updated2026-09-30
Privacy policy last updated2026-09-30
Customer content may train modelsyes
Terms restrict automated accessnot found in the text
Terms restrict benchmarkingnot found in the text
Terms or service can change without noticenot found in the text
Arbitration or class-action waivernot found in the text
Popularitynone318 npm/wk, 156 PyPI/wk

Verdicts

Liquid d1

The hosted API costs $0.04 per million input tokens and takes TypeSafe's System One request, and the d1-3B weights run locally through Transformers or llama.cpp. Liquid's terms allow it to train on API content, and no status page, rate limits or error reference were found. The family launched between 22 September and 7 October 2026.

Drex 1.5

The hosted endpoint has a public OpenAPI document, published limits and pinned model versions, at $0.05 per million input tokens with no output charge. The #1 under 10B claim rests on Nace's own run, since Drex is absent from both public boards. Weights carry Open RAIL-M, which requires a commercial licence above $1 million in revenue or funding.

Before you call either

Liquid d1

  1. POST to https://api.liquid.ai/decisions/v1/systemone with a liquid_ key as a Bearer header. This is not a chat-completions endpoint
  2. Use d1 for images. d1:free is text-only and answers that it does not accept images
  3. Send images as Base64 data URLs in images, at most 8, with the whole JSON body under 4.5 MB. Remote image URLs are refused
  4. Budget tokens per question. Each question is billed as its own prompt, with its text and every image counted again
  5. Don't send confidential content to the hosted API, since the terms allow training on it. Run d1-3B locally for that data

Drex 1.5

  1. Call https://console.nace.ai/v1/systemone with Authorization: Bearer nace_sk_..., and pin model drex-v1.5 rather than drex-latest in production.
  2. Stop on 402 insufficient_credit or 402 payment_required until credit is topped up or the unpaid invoice is paid.
  3. Retry 429 and 529 after retry-after-ms. On a 422 for an unknown model, use one of the ids the error message lists.
  4. Keep state below 131,072 tokens and the body below 1,048,576 bytes, and send at most 512 questions per request.
  5. Keep the key on a server. A key in browser code is exposed, and the /v1 routes send no Access-Control-Allow-Origin header.
  6. Check usage.input_tokens and the usage CSV after retries, since /v1/systemone documents no idempotency key.

Questions

Which is better for AI agents, Liquid d1 or Drex 1.5?

Drex 1.5 scores 69.7 (B) on agent readiness against Liquid d1's 43.5 (E), and leads in every scored category.

Do Liquid d1 and Drex 1.5 need an API key?

Both need an API key.

Can an agent call Liquid d1 and Drex 1.5 without installing anything?

Yes. Liquid d1 has a hosted endpoint at https://api.liquid.ai/decisions/v1/systemone and Drex 1.5 at https://console.nace.ai/v1/systemone.

Other comparisons with Liquid d1 or Drex 1.5

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