Grok 4.1 Fast vs Mistral Small 3.1 24B

Across our 12-test benchmark suite, Grok 4.1 Fast wins 10 tests outright, ties 2, and loses 0 against Mistral Small 3.1 24B.

Tool Calling (4 vs 1): This is the most consequential gap. Grok 4.1 Fast scores 4/5 (rank 18 of 54); Mistral Small 3.1 24B scores 1/5 (rank 53 of 54) and is flagged with a no_tool calling quirk in the payload. This is a hard blocker for any workflow involving function calls, APIs, or agentic pipelines.

Agentic Planning (4 vs 3): Grok 4.1 Fast ranks 16th of 54; Mistral Small ranks 42nd of 54. For multi-step goal decomposition and failure recovery, the gap is meaningful — Mistral scores below the p50 of 4 while Grok matches it.

Persona Consistency (5 vs 2): Grok 4.1 Fast ties for 1st among 53 models; Mistral Small ranks 51st of 53, sharing that score with only one other model. For chatbot, roleplay, or customer support applications requiring stable character, Mistral Small is near the bottom of the field.

Creative Problem Solving (4 vs 2): Grok 4.1 Fast ranks 9th of 54; Mistral Small ranks 47th of 54. Mistral generates ideas that scored as obvious or infeasible in our testing.

Strategic Analysis (5 vs 3): Grok 4.1 Fast ties for 1st of 54; Mistral Small ranks 36th of 54. For nuanced tradeoff reasoning, Mistral falls well below the median.

Structured Output (5 vs 4): Grok 4.1 Fast ties for 1st of 54; Mistral Small ranks 26th of 54. Both are above the p50 of 4, but Grok's JSON schema compliance is tighter in our tests.

Faithfulness (5 vs 4): Grok 4.1 Fast ties for 1st of 55; Mistral Small ranks 34th of 55. Both score above the median, but Grok is more reliable at sticking to source material.

Multilingual (5 vs 4): Grok 4.1 Fast ties for 1st of 55; Mistral Small ranks 36th of 55. Mistral scores below the p50 of 5 here.

Classification (4 vs 3): Grok ties for 1st of 53; Mistral ranks 31st of 53. For routing and categorization tasks, this is a real gap.

Constrained Rewriting (4 vs 3): Grok ranks 6th of 53; Mistral ranks 31st of 53.

Long Context (5 vs 5, tied): Both models tie for 1st of 55 on long-context retrieval at 30K+ tokens. Note that Grok 4.1 Fast has a 2,000,000-token context window vs Mistral Small's 128,000-token window — a massive practical difference if your use case involves very long documents, even though both score 5/5 on our 30K+ retrieval test.

Safety Calibration (1 vs 1, tied): Both models tie at rank 32 of 55, scoring 1/5. Neither model performs well here relative to the broader field, which shows a p75 of just 2/5 — so this is a market-wide weak spot, not unique to either model.

Grok 4.1 Fast charges $0.20/M input tokens and $0.50/M output tokens. Mistral Small 3.1 24B costs $0.35/M input and $0.56/M output — making Mistral 75% more expensive on input and 12% more expensive on output. At 1M tokens/month (roughly a small production API), you'd pay $0.70 for Grok 4.1 Fast vs $0.91 for Mistral Small — a modest $0.21 difference. At 10M tokens/month, that gap becomes $2.10, and at 100M tokens/month it reaches $21. The cost inversion here is important: Mistral Small 3.1 24B is the pricier model despite weaker benchmark performance. For cost-sensitive developers who assumed the Mistral small-tier model would be the budget option, this comparison flips that assumption. The only scenario where Mistral's pricing gets competitive is if you self-host the open-weight version, but the payload does not indicate open-weight availability for either model.

Choose Grok 4.1 Fast if: You need tool calling or agentic workflows — Mistral Small's no_tool calling quirk makes it a non-starter for those use cases. Also choose Grok 4.1 Fast for customer support bots (persona consistency 5 vs 2), complex reasoning or strategic analysis (5 vs 3), creative ideation (4 vs 2), or any production workload where you want both better performance and lower cost. The 2M context window is also a decisive advantage for long-document applications.

Choose Mistral Small 3.1 24B if: Your workload is purely text-in, text-out with no tool calling, you're working within a 128K context window, and you're already integrated into the Mistral ecosystem. Even then, the payload data does not support Mistral Small outperforming Grok 4.1 Fast on any benchmark we tested — so Mistral Small 3.1 24B is a harder sell at its higher input price. It could be relevant if you have existing Mistral infrastructure or need multimodal (text+image) input without file support, though Grok 4.1 Fast also supports text+image+file input.