Grok Build 0.1
xAI · released May 20, 2026
- Type
- Closed
- Input
- $1.00
- Output
- $2.00
- Cached
- None held
List price · per 1M tokens · xAI at 256K context · machine-readable source ↗
Our take
Written Sep 30, 2026Grok Build 0.1 is a hosted-only model with one clear speciality: picking the right tool and not inventing one, where it places 8th of 55 on Arena Agent · Tool use as of 25 Sep 2026. Everywhere else its measured results sit near the bottom of the field, so it is a narrow pick rather than a general one.
Reach for it when the job is agent work that hinges on choosing the right tool, or when long documents would otherwise have to be split before sending. We list no download for it, so using it means choosing a host. Skip it if you need code written or maths solved, or if you need an agent to recover after a command fails or hold a course correction.
The case for it
- Tool selection is the one thing it does well: 8th of 55 on Arena Agent · Tool use as of 25 Sep 2026, an inverse-propensity score for calling the right tool and not inventing one, far ahead of its own 49th of 55 on the parent Arena Agent board.
- Long inputs need not be split up first, though whether it recalls everything inside them is unverified in our data.
- Files and images go in with the question, so a document or a screenshot does not have to be retyped as prose.
The case against it
- Coding is among the weakest measured areas: 58th of 58 on LiveBench Coding as of 25 Jun 2026, a percentage average over code generation and completion tasks.
- Maths and reasoning sit near the bottom of the same field: 55th of 58 on LiveBench Mathematics and 50th of 58 on LiveBench Reasoning as of 25 Jun 2026.
- Agent sessions that go wrong tend not to come back: 53rd of 55 on Arena Agent · Recovery as of 25 Sep 2026, and 41st of 55 on task outcome.
How good is it?
A text model for calling tools to carry out requests, though multi-step work and changing course are weaker spots.
- calling tools to carry out requestsArena Agent · Tool use · 8th of 55
- multi-step work it carries out for youArena Agent · 49th of 55
- changing course when you give new instructionsArena Agent · Steerability · 45th of 55
- getting back on track after a step failsArena Agent · Recovery · 53rd of 55
EverydayGeneral questions and everyday reasoning
Not yet scored on Arena Text (overall). It is on LiveBench Data Analysis, in 41st of 58 with 70.79.
CodingWriting and fixing code on its own
Not yet scored on Arena Coding. It is on LiveBench Coding, in 58th of 58 with 65.39.
AgenticPlanning, calling tools, staying on task
Arena Agent49th of 55 · −0.129
WritingDrafting and rewriting prose
Not yet scored on Arena Creative Writing. It is on LiveBench Language, in 51st of 58 with 72.46.
Placings on Arena's agent boards, from live sessions people ran themselves. A model can lead on one of these and sit mid-field on the others.
Boards this model appears on that none of the ratings above are built on.
Every published score for this model13 scoresEvery figure we hold, from 13 boards, with who ran it and a link to the source — including the boards no rating above is built on.
Where to rent it
Prices checked 2 hours ago — each listing carries its own date.
xAI, direct and through OpenRouter
The lab is also the cheapest we hold. The strip above and this offer are the same one, so nothing on this page undercuts xAI on 256K of context.
- per 1M tokens
- $1.00 in / $2.00 out
- Context served
- 256K
- Throughput
- Not measured
| Provider | In / out per 1M tokens | Context | Throughput | Trains on prompts | Logs prompts | Zero retention |
|---|---|---|---|---|---|---|
| OpenRouterOpenRouter's own listing | $1.00 / $2.00checked 2 hours ago | 256K | not measured | Unknown | Unknown | Unknown |
| xAIDirect and through OpenRouter | $1.00 / $2.00checked 2 hours ago | 256K256K max reply direct230K max reply through OpenRouter | 101 tok/sthrough OpenRouter | DirectUnknownThrough OpenRouterNo | DirectUnknownThrough OpenRouterYes30 days | DirectUnknownThrough OpenRouterConfirmed |
| xAIpriority tierThrough OpenRouter | $2.00 / $4.00checked 2 hours ago | 256K230K max reply | 73 tok/s | No | Yes30 days | Confirmed |
OpenRouterAcross the 3 listings we hold: 2 say they do not train on prompts (1 of them only through OpenRouter), 0 say they do and 1 does not say. 2 appear in the zero-retention registry we check (1 of them only through OpenRouter); the rest are unknown to us.
What each host's API supports
From the parameter list each endpoint publishes. Streaming is omitted: nothing we hold reports it, for any model.
| Provider | Tool calling | JSON output | Strict schema |
|---|---|---|---|
| OpenRouterOpenRouter's own listing | ✓ | ✓ | ✓ |
| xAIDirect and through OpenRouter | ✓ | ✓ | ✓ |
| xAIpriorityThrough OpenRouter | ✓ | ✓ | ✓ |
Tool calling: 3 of 3 listings say yes. JSON output: 3 of 3 listings say yes. Strict schema: 3 of 3 listings say yes.
When we formed this view
Recent changes
What moved
first indexed by our pipelineEach date is the day we first saw the change, or the day the maker announced it.
What we do not know about this model yet
- Nothing we hold says whether an endpoint streams, so we do not show it either way.
- 1 of 3 listings does not say whether it trains on prompts, and 1 answers only through OpenRouter, not for its own listing.
- We hold no batch or off-peak rate for any of its listings.
Licence and identifiers
What the licence allowsWe hold no licence record for this model. Inside are the identifiers you need to pull it — its Hugging Face repo where we have one, our slug and a machine-readable card.
Licence
We hold no licence record for this model, and no record of published weights either — so we can neither summarise its terms nor point you at the weights.
Identifiers
- Takes in, gives back
- Text, images and documents in, text out
- Catalogue slug
- x-ai-grok-build-0-1