Language modelLimited access
Jamba Large 1.7
AI21
- Released
- -
- Data date
- October 3, 2026
Jamba Large 1.7 focuses on stronger grounding in supplied context, according to AI21. In the company’s FACTS evaluation, its score rises from 0.758 in version 1.6 to 0.832. The hybrid SSM-Transformer architecture handles 256K context tokens.
AI21 lists 398 billion total parameters and 94 billion active parameters. The weights use the Jamba Open Model License, with Hugging Face access requiring acceptance of the terms and sharing contact information.
Measurements without matching peer values
These measurements have no matching peer values under the same test conditions. Their original values and sources remain available here.
Vectara hallucination rate (Show measurement, test conditions, and source)
- Source value
- 9.7
- Score
- 9.7
- Metric
- Vectara hallucination rate
- Unit
- %
- Category
- hallucination
- Direction
- Lower is better
- Source type
- independent-evaluator
- Evaluator
- Vectara Hallucination Leaderboard
- Status
- active
- Retrieved at
- 2026-10-04
- Methodology
- Independent evaluation. ai21labs/jamba-large-1.7-2025-07; fixed article-summary prompt, commercial HHEM threshold <0.5; answered summaries only; answer rate 98.9%.
- Context
- Automated summary evaluation, not a general factual-accuracy measure. Exact row sample count, run date, and reasoning setting are unspecified. The complementary consistency rate describes the same evaluation, not a second test.
Vectara factual consistency rate (Show measurement, test conditions, and source)
- Source value
- 90.3
- Score
- 90.3
- Metric
- Vectara factual consistency rate
- Unit
- %
- Category
- hallucination
- Direction
- Higher is better
- Source type
- independent-evaluator
- Evaluator
- Vectara Hallucination Leaderboard
- Status
- active
- Retrieved at
- 2026-10-04
- Methodology
- Independent evaluation. ai21labs/jamba-large-1.7-2025-07; same HHEM article-summary evaluation as the hallucination rate; answer rate 98.9%.
- Context
- Complementary result from the same summaries, not independent corroboration or a general knowledge score. Exact run date, sample count, and reasoning setting are unspecified.
FACTS (Show measurement, test conditions, and source)
- Source value
- 0.832
- Score
- 0.832
- Metric
- FACTS
- Unit
- No unit provided
- Category
- hallucination
- Direction
- Higher is better
- Source type
- vendor-reported
- Evaluator
- AI21 Jamba Large 1.7 model card
- Status
- active
- Retrieved at
- 2026-10-04
- Methodology
- Vendor-reported result. Exact Jamba Large 1.7 column in AI21's Grounding and instruction-following improvements table; FACTS grounding result. Benchmark-specific serving and evaluation settings are not documented.
- Context
- Vendor-reported raw score with an unspecified scale, not normalized to a percentage. Exact benchmark version, harness, sample count, sampling, reasoning setting, and run date are not supplied. Inference examples are not the benchmark protocol.
IFEcal (Show measurement, test conditions, and source)
- Source value
- 0.84
- Score
- 0.84
- Metric
- IFEcal
- Unit
- No unit provided
- Category
- instruction-following
- Direction
- Higher is better
- Source type
- vendor-reported
- Evaluator
- AI21 Jamba Large 1.7 model card
- Status
- active
- Retrieved at
- 2026-10-04
- Methodology
- Vendor-reported result. Exact Jamba Large 1.7 column in AI21's Grounding and instruction-following improvements table; steerability result labelled IFEcal in the source. Benchmark-specific serving and evaluation settings are not documented.
- Context
- Vendor-reported raw score with an unspecified scale. The source spells the benchmark IFEcal; no equivalence to IFEval is established. Exact version, harness, sample count, sampling, reasoning setting, and run date are not supplied. Inference examples are not the benchmark protocol.
Sources and data date
Every statement links to its underlying documentation or leaderboard.
| Type | Evidence and data date |
|---|---|
| Research status | Research date October 4, 2026. 7 source URLs checked. This documents the inspected sources, not an exhaustive inventory of every publication. |
| Additional source | AI21 Jamba Large 1.7 model card (retrieved October 3, 2026) · AI21 Jamba Large 1.7 model card · Editorial description reviewed October 4, 2026 |
| Additional source | Vectara Hallucination Leaderboard (retrieved October 4, 2026) |
| Additional source | AI21 Jamba Large 1.7 model card (retrieved October 4, 2026) |
| Additional source | Model metadata (retrieved October 4, 2026) |
| Additional source | Model metadata (retrieved October 4, 2026) |
| Additional source | Model metadata (retrieved October 4, 2026) |