Best LLM for AI Agents
Ranked on multi-step reasoning, tool-use reliability, and long-horizon stability. Agentic workloads amplify small accuracy gaps.
Updated April 2026. Top 3 this month: GPT-5, Gemini 2 Pro, Claude Opus 4.7.
How we rank
Agents chain dozens of tool calls per run. Even a 95%-reliable tool-use model compounds down to near-zero after 20 steps, so the gap between the top model and the runner-up matters a lot. We weight SWE-Bench Verified heavily because it is the best proxy for long-horizon agentic success, then reasoning benchmarks, then price.
Pillars and weights: SWE-Bench Verified (40%) · AgentBench (30%) · MMLU (15%) · price (15%). Our full methodology is published on the methodology page.
Top ranked models
| Rank | Model | Provider | Input $/1M | Output $/1M | Context |
|---|---|---|---|---|---|
| 1 | GPT-5 | OpenAI | $1.25 | $10.00 | 200,000 |
| 2 | Gemini 2 Pro | $3.50 | $10.50 | 2,000,000 | |
| 3 | Claude Opus 4.7 | Anthropic | $5.00 | $25.00 | 200,000 |
| 4 | DeepSeek V3.2 | DeepSeek | $0.27 | $1.10 | 128,000 |
| 5 | DeepSeek V3 | DeepSeek | $0.27 | $1.10 | 128,000 |
| 6 | o4-mini | OpenAI | $0.40 | $1.60 | 200,000 |
| 7 | GPT-5 mini | OpenAI | $0.25 | $2.00 | 400,000 |
| 8 | Claude 3.5 Haiku | Anthropic | $0.80 | $4.00 | 200,000 |
| 9 | o3-mini | OpenAI | $1.00 | $4.00 | 200,000 |
| 10 | Claude Haiku 4.5 | Anthropic | $1.00 | $5.00 | 200,000 |
Tips for ai agents
- Plan for retries. Instrument every tool call with structured logging and a budget ceiling.
- Prefer models with native structured-output mode to avoid JSON-fixup loops.
- Cache system prompts aggressively — agentic flows repeat the same preamble many times.
Frequently asked questions
Which LLM is best for agents?
As of April 2026, our weighted top 3 are GPT-5, Gemini 2 Pro, Claude Opus 4.7.
How much does accuracy matter at each step?
A lot. A 2% per-step improvement can double end-to-end reliability on a 20-step task. Prefer the top-tier model for agent loops and a cheaper model for one-shot tasks.
Do open-weight models keep up for agents?
Open-weight models are catching up on tool use but still trail the frontier for long-horizon agents. Evaluate on your actual task before committing.
Related tasks
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Data refreshed daily via our snapshot cron. See our public JSON API for programmatic access.