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Head to head · Decision models · October 2026 research run

Drex 1.5 vs OpenAI Decisions API

OpenAI Decisions API scores 71.5 (BB) on agent readiness against Drex 1.5's 69.7 (B), and leads in 5 of 7 scored categories. Drex 1.5 leads on reliability and payments & pricing. Both do decision models.

Best decision models for AI agents · All 91 decisions comparisons

Drex 1.5Nace AI, Inc. (Nace.AI) · Model API B69.7/100#172 of 954 OpenAI Decisions APIOpenAI · Model API BB71.5/100#123 of 954

Which one, for what

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 53
  • Payments & pricing, 40 against 30

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.

OpenAI Decisions API BB

Best for High-volume yes or no checks, routing among fixed options and rubric scoring over text and images, for teams already on an OpenAI key.

Ahead on

  • Security & auth, 83 against 65
  • Maintenance & community, 77 against 65
  • Transparency & trust, 83 against 63

Also in its favour

  • Agent-ready, a grade of BB or better

Watch for

Public beta released on 6 October 2026. The guide expects general availability in the coming weeks and gives no date

Score by category

CategoryWeight this runDrex 1.5OpenAI Decisions APIEdge
Reliability16%208053Drex 1.5 +27
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28889OpenAI Decisions API +1
Agent ergonomics13%16.28587OpenAI Decisions API +2
Security & auth14%17.56583OpenAI Decisions API +18
Payments & pricing10%12.54030Drex 1.5 +10
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86577OpenAI Decisions API +12
Transparency & trust7%8.86383OpenAI Decisions API +20
Negative events≤15-20
TotalB 69.7/100BB 71.5/100

Facts side by side

FactDrex 1.5OpenAI Decisions API
KindModel APIModel API
VendorNace AI, Inc. (Nace.AI)OpenAI
Hosted endpointhttps://console.nace.ai/v1/systemonehttps://api.openai.com/v1/decisions
TransportsHTTPHTTP
AuthAPI keyAPI key
PricingFreemiumPay per use
Price for decision modelsnot published$0.10 per 1M tokens
x402nono
LicenceHosted 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.Proprietary service under OpenAI's services agreement. The official SDKs are Apache-2.0
Read-only variant documentednono
llms.txtyesyes
Last release2026-09-282026-10-06
Terms last updatedcouldn't be read
Privacy policy last updatedcouldn't be read
Customer content may train modelscouldn't be read
Terms restrict automated accesscouldn't be read
Terms restrict benchmarkingcouldn't be read
Terms or service can change without noticecouldn't be read
Arbitration or class-action waivercouldn't be read
Popularity318 npm/wk, 156 PyPI/wk32k stars

Verdicts

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.

OpenAI Decisions API

Typed predicate, choice and score answers with probabilities, up to 200 questions a call, at $0.10 per million input tokens with no output charge. It is a public beta released on 6 October 2026, with one model alias, no dated snapshot, no Batch route and no SLA found.

Before you call either

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.

OpenAI Decisions API

  1. Put independent questions about one input in a single questions array. Send a separate request when a question depends on an earlier answer
  2. Check each answer's type before reading it. A question can come back as refusal while the others in the same request are answered
  3. Encode images as base64 data URLs. Hosted URLs and file_id inputs are rejected
  4. Give a choice question a fallback value such as other, and set thresholds from your own labelled examples
  5. Use Python SDK 3.26.0 or JavaScript 7.30.0 or later, and follow Retry-After on 429 and 503

Questions

Which is better for AI agents, Drex 1.5 or OpenAI Decisions API?

OpenAI Decisions API scores 71.5 (BB) on agent readiness against Drex 1.5's 69.7 (B), and leads in 5 of 7 scored categories. Drex 1.5 leads on reliability and payments & pricing.

Do Drex 1.5 and OpenAI Decisions API need an API key?

Both need an API key.

Can an agent call Drex 1.5 and OpenAI Decisions API without installing anything?

Yes. Drex 1.5 has a hosted endpoint at https://console.nace.ai/v1/systemone and OpenAI Decisions API at https://api.openai.com/v1/decisions.

Other comparisons with Drex 1.5 or OpenAI Decisions API

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