xAI's fast agentic tool-calling model with a 2M context window and built-in reasoning
- Context
- 2M
- Released
- 11mo ago
Sources:models.dev
Benchmarks
DeepSWE is the primary coding benchmark where an exact model evaluation exists. Other sourced evaluations appear below; missing scores are not zero.
Not evaluated in DeepSWE 1.1 as of 2026-09-22. Results are only shown for exact model versions in the official dataset. Official leaderboard.
No benchmark results have been matched to this model yet.
Specifications
- Developer
- xAI
- Model family
- Grok
- Type
- Language model
- Predecessor
- —
- Successor
- —
- Released
- November 19, 2025
- Model ID
xai/grok-4.1-fast-reasoning- Openness
- Closed
- License
- —
- Input modalities
- text, image
- Output modalities
- text
- Modality
- text+image->text
- Max output tokens
- 30K
- Hugging Face
- —
- Source freshness
- Metadata synced Oct 8, 2026, 10:17 PM UTC
Additional source evidence
- Source model
- xai/grok-4.1-fast-reasoning
- Source family
- grok
- Last updated
- 2025-11-19
- Model context
- 2M
- Model output limit
- 30K
- Open weights
- No
- File attachments
- Yes
- Reasoning
- Yes
- Tool calling
- Yes
- Structured output
- Yes
- Temperature control
- Yes
Complete source record (JSON)
{
"id": "xai/grok-4.1-fast-reasoning",
"name": "Grok 4.1 Fast (Reasoning)",
"description": "xAI's fast agentic tool-calling model with a 2M context window and built-in reasoning",
"family": "grok",
"last_updated": "2025-11-19",
"attachment": true,
"reasoning": true,
"tool_call": true,
"structured_output": true,
"temperature": true,
"modalities": {
"input": [
"text",
"image"
],
"output": [
"text"
]
},
"limit": {
"context": 2000000,
"output": 30000
},
"release_date": "2025-11-19",
"open_weights": false
}Infrastructure
Provider availability
Provider endpoint data will appear after this model's first OpenRouter endpoint sync.