Grok 4.20 Reasoning

xAI
Grok 4.20 Reasoning is aimed at one controllable, multi-step reasoning and tool-calling run. The model accepts text and images and provides one million tokens of context for substantial working material.
This variant uses the API identifier grok-4.20-0309-reasoning. It separates the single reasoning and tool-calling run from Grok 4.20 Multi-Agent, which is aimed at parallel research. xAI publishes neither weights nor a parameter count.
The index averages rank percentiles from 10 documented comparison cohorts.
Page 1 of 3
Overall
502 technical decision points from engineering and research workflows. Each choice is presented in both answer orders. The overall score averages engineering and research and requires both answer orders to be correct. Unparseable responses count as wrong. Reasoning settings and output budget are part of the setup.
Note (Grok 4.20 Reasoning): 459 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 0 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 0 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 0 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 10 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 0 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 17 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 0 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 0 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 3 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 2 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 112 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 24 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
Note: 93 of 1,004 responses were unparseable and counted as wrong. Not a Gradually test.
higher is betterAs of September 26, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall · Task fully resolved
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall · All-pass
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
Overall
higher is betterAs of September 29, 2026Scale: 0% - 100%
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One SVG prompt and fixed output settings. Captures are shown only with 0 reported reasoning tokens or documented lack of reasoning controls. Identical test conditions do not make the models' internal compute identical.

A community classic for free-form SVG drawing.
Grok 4.20 Reasoning

Reasoning (requested): high
Visually reviewed. This individual test does not establish overall model quality.
Generate an SVG of a pelican riding a bicycle
Token limit including reasoning: 8,192 tokens
Task origin (Simon Willison)23.5 / 100
| Specification | Value and source |
|---|---|
| Weights | ProprietarySource |
| Access | APISource |
| Context window | 1,000,000 tokensSource |
| Notes | 1M context, reasoning mode and agentic tool calling, parameter count not disclosedSource |
| API model ID | grok-4.20-0309-reasoningSource |
| Source status | activeSource |
| Release | 2026-03-10Source |
| Maximum output | not statedSource |
| Input | Text, ImageSource |
| Output | TextSource |
| Tool calling | YesSource |
| Structured output | YesSource |
| Model aliases | grok-4.20-reasoningSource |
| Reasoning mode | low, medium, highSource |
| Type | Evidence and data date |
|---|---|
| Speed | SpaceXAI. Output speed after the first streaming chunk, not total response time. Classified as deprecated by Artificial Analysis. Artificial Analysis maintains only the default 10K-input workload there. Retrieved September 8, 2026. |
| Price | Base API prices without caching or batch discounts. Higher context tiers and other rates are listed under Costs. |
| Input | Documented modalities. Retrieved September 8, 2026. |
| Output | Documented modalities. Retrieved September 8, 2026. |
| Research status | Research date September 8, 2026. 3 source URLs checked. This documents the inspected sources, not an exhaustive inventory of every publication. |
| Not found in the inspected sources | parameters-billions Original wording xAI does not publish parameter counts on the model page. |
| Not found in the inspected sources | active-parameters-billions Original wording xAI does not publish active parameter counts on the model page. |
| Not found in the inspected sources | knowledge-cutoff Original wording The official xAI model page did not state a knowledge cutoff. |
| Not found in the inspected sources | profile-benchmarks Original wording The exact model documentation page exposed capabilities and pricing but no benchmark table. |
| Additional source | Taste-Bench paper (retrieved September 26, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | Vals AI (retrieved September 29, 2026) |
| Additional source | OpenRouter: Popularity index (derived), CC BY 4.0 |
| Additional source | Vercel AI Gateway: Popularity index (derived), CC BY 4.0 |
| Additional source | Creative Commons Attribution 4.0 |