Best LLM for agents (October 2026)
As of 21 Oct 2026, the best LLM for agents and tool use on independent benchmarks is Grok 4.1 Fast (thinking) by SpaceXAI (agents score 70.5), ahead of o3 (agents score 70.3) and Claude Sonnet 5.5 (max) (agents score 69.8).
Ranked on the agents-and-tools category: function calling, multi-step tool use and agentic task boards such as Terminal-Bench, BFCL and τ²-bench. Models need results on at least two of them.
145 models qualify · data as of 21 Oct 2026 · rebuilt once a day (the run starts at 22:03 UTC)
Grok 4.1 Fast thinking#1 here: agents score 70.5Best value
DeepSeek V4 Flash maxmost index points per dollar among the top 15 (61.1 at $0.175/M)Best open weights DeepSeek V4 Flash maxhighest-ranked model here you can run yourself (#4)Fastest of the top 15
o3 149 output tokens per secondHead to head: o3 vs Claude Sonnet 5.5 (#2 vs #3)
| # | Model | Agents score | Index | Price $/M | Speed tok/s |
|---|---|---|---|---|---|
| 1 | Grok 4.1 FastthinkingSpaceXAI | 70.5 | 54.8 | $0.275 | – |
| 2 | o3OpenAI | 70.3 | 59.5 | $3.50 | 149 |
| 3 |  Claude Sonnet 5.5maxAnthropic | 69.8 | 69.5 | $4.00 | 137 |
| 4 | DeepSeek V4 FlashmaxDeepSeek | 67.2 | 61.1 | $0.175 | 145 |
| 5 | GPT-5.6 SolmaxOpenAI | 66.5 | 68.0 | $8.00 | 84 |
| 6 |  Muse SparkMeta | 66.1 | 64.4 | – | – |
| 7 | Muse Spark 1.3maxMeta | 65.6 | 67.2 | $2.00 | 128 |
| 8 | Claude Opus 4.7Anthropic | 65.5 | 63.4 | $10.00 | 60 |
| 9 | Claude Fable 5maxAnthropic | 65.0 | 69.4 | $20.00 | 67 |
| 10 | GPT-6 AstramaxOpenAI | 64.8 | 70.6 | $20.00 | 64 |
| 11 | GPT-6.1 SolmaxOpenAI | 64.7 | 70.0 | $4.00 | 55 |
| 12 | Claude Opus 5maxAnthropic | 64.3 | 68.9 | $10.00 | 54 |
| 13 |  Qwen3.8-Flash-NextAlibaba | 64.1 | 60.3 | $0.230 | 52 |
| 14 | DeepSeek V4 PromaxDeepSeek | 63.7 | 62.7 | $1.98 | 103 |
| 15 | GPT-5.4xhighOpenAI | 63.6 | 64.8 | $5.63 | 112 |
Full ranked list (145 models) · Best for coding agents, with the weighting stated · Methodology · the LLM benchmarks behind this ranking
Best LLM for agents: questions
- What is the best LLM for agents and tool use in October 2026?
- As of 21 Oct 2026, the best LLM for agents and tool use on independent benchmarks is Grok 4.1 Fast (thinking) by SpaceXAI (agents score 70.5), ahead of o3 (agents score 70.3) and Claude Sonnet 5.5 (max) (agents score 69.8). BenchLeader reconciles 229 benchmarks from 43 benchmark publishers and rebuilds the ranking once a day (the run starts at 22:03 UTC).
- Which is the best value?
- DeepSeek V4 Flash (max) gives the most BenchLeader Index points per dollar among the top 15 here: 61.1 at $0.175 per million tokens blended, against $0.275 for Grok 4.1 Fast.
- What is the best open-weights option?
- DeepSeek V4 Flash (max) by DeepSeek is the highest-ranked open-weights model on this list, at #4.
- How is this ranked?
- Ranked on the agents-and-tools category: function calling, multi-step tool use and agentic task boards such as Terminal-Bench, BFCL and τ²-bench. Models need results on at least two of them. Every score comes from an independent publisher and links to its source on the model page; self-reported launch numbers are excluded.
Cite as: BenchLeader, “Best LLM for agents (October 2026)”, https://www.benchleader.com/best/llm-for-agents, data as of 21 Oct 2026.