Head to head · Decision models · October 2026 research run

pplx-decider vs Vela 2.0

Vela 2.0 scores 66.5 (B) on agent readiness against pplx-decider's 62.9 (B), and leads in 3 of 7 scored categories. pplx-decider leads on schema & documentation. Both do decision models. pplx-decider is cheaper for decision models, $0 against $0 per 1M tokens.

Best decision models for AI agents · All 66 decisions comparisons

Which one, for what

pplx-decider B

Good for High-volume classification, routing and rubric scoring over text and images where a team wants a low hosted price and the option to run the same weights itself.

Ahead on

  • Schema & documentation, 90 against 78

Also in its favour

  • Cheaper for decision models, $0 against $0 per 1M tokens
  • A hosted endpoint, with nothing to install

Watch for

The Decisions API was released in October 2026, so its incident record is days long, and Perplexity's FAQ says it gives no uptime guarantee

Vela 2.0 B

Good for Self-hosted routing and guardrail checks in one call, where span offsets for personal data or unsupported claims matter.

Ahead on

  • Payments & pricing, 60 against 25
  • Maintenance & community, 84 against 62

Also in its favour

  • No key needed to call it
  • Open source

Watch for

No version tags on the four Hub repositories, and the 4B and 9B weights were replaced in place on 3 October 2026

Score by category

CategoryWeight this runpplx-deciderVela 2.0Edge
Reliability16%206157pplx-decider +4
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.29078pplx-decider +12
Agent ergonomics13%16.27679Vela 2.0 +3
Security & auth14%17.56160pplx-decider +1
Payments & pricing10%12.52560Vela 2.0 +35
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.86284Vela 2.0 +22
Transparency & trust7%8.85248pplx-decider +4
Negative events≤1500
Total62.9 · B66.5 · B

Facts side by side

Factpplx-deciderVela 2.0
KindModel APIModel API
VendorPerplexityvLLM Semantic Router project and KR Labs
Hosted endpointhttps://api.perplexity.ai/v1/decisionsno (local only)
TransportsHTTPHTTP
AuthAPI keyNone
PricingPay per useFree
Price for decision modelsfreefree
x402nono
LicenceApache-2.0 for the published weights. The hosted Decisions API is a proprietary serviceApache-2.0 (weights, code and documentation). The 0.3B's tokeniser keeps the Gemma Terms of Use, and training data keeps its own licences
Read-only variant documentednono
llms.txtyesno
Last release2026-10-052026-10-06
Terms last updatedcouldn't be readno document linked
Privacy policy last updatedcouldn't be readno document linked
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
Popularitynone6.1k stars

Verdicts

pplx-decider

The hosted Decisions API has an OpenAPI description, typed questions, documented limits and a published price of $0.02 per million input tokens, and the v1.1 weights are public under Apache-2.0. The API is days old, the official Python SDK has no method for it, and the governing terms and privacy notice could not be read on 9 October 2026.

Vela 2.0

One self-hosted call answers routing, prompt-attack, personal-data and unsupported-claim questions with probabilities and character offsets, under Apache-2.0 with SHA-256 manifests. The models are days old and carry no Hub version tags, and the three larger sizes keep 74 to 89 per cent of their Decision 2.0 bases on the Jev Decision Index by the authors' figures.

Before you call either

pplx-decider

  1. Send Authorization: Bearer. A key in x-api-key returns 401 on this endpoint.
  2. Set model on every request. A missing or unknown model returns 400, and the guide shows a -latest name rejected.
  3. Resize images to 2,048 tiles of 32 by 32 pixels or fewer before sending. Larger images end in a 504 after about a minute.
  4. Check the HTTP status before parsing an error. 404 and 405 have empty bodies, 504 can be HTML, and error.code changes type.
  5. For the weights, use the repository's autojev code. The card says default causal inference does not reproduce the evaluated setup.

Vela 2.0

  1. Pin a commit hash with revision= when loading from the Hub. The repositories have no tags and main has changed since launch
  2. Send the served name in model, for example vllm-sr/Vela-2.0-4B. The bundled server answers 422 to any other name
  3. Name span questions pii, halu or toxic, or set "head": "router", to get the trained router head. Other labels go to the broad head
  4. Keep input under 16,384 tokens a sequence (8,192 on the 0.3B). The bundled server answers 413 when the questions alone don't fit
  5. Set VELA2_API_KEY before binding the bundled server beyond 127.0.0.1, and keep the model runtime on a trusted network

Questions

Which is better for AI agents, pplx-decider or Vela 2.0?

Vela 2.0 scores 66.5 (B) on agent readiness against pplx-decider's 62.9 (B), and leads in 3 of 7 scored categories. pplx-decider leads on schema & documentation.

Which is cheaper for decision models, pplx-decider or Vela 2.0?

pplx-decider, at free against free for Vela 2.0. These are the vendors' published prices for the job.

Do pplx-decider and Vela 2.0 need an API key?

pplx-decider needs an API key. Vela 2.0 needs no key.

Can an agent call pplx-decider and Vela 2.0 without installing anything?

pplx-decider has a hosted endpoint at https://api.perplexity.ai/v1/decisions. No hosted endpoint is listed for Vela 2.0.

Are pplx-decider and Vela 2.0 open source?

No open-source release is listed for pplx-decider. Vela 2.0 is open source (Apache-2.0 (weights, code and documentation). The 0.3B's tokeniser keeps the Gemma Terms of Use, and training data keeps its own licences).

Other comparisons with pplx-decider or Vela 2.0

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