Best AI Model for Autonomous AI Agents
Building autonomous agents that use tools, browse the web, execute code, and complete multi-step tasks.
Our Verdict
Claude Opus 4.6 is the undisputed leader for agents — best-in-class tool-use reliability, strong reasoning, and 32K output prevents truncated tool sequences. GPT-5.3 Codex is the coding-focused agent pick with 96.5% HumanEval and 65K output. For budget agents, Claude Sonnet 4.6 delivers 90% of Opus capability at 1/5th the cost. Don't use open-source or budget models for agents — unreliable tool-calling leads to cascading failures.
Top Picks
Best tool-use reliability + reasoning depth for multi-step workflows
Best for: General-purpose autonomous agents
Input
$5/1M
Output
$25/1M
Context
200K
Max Output
32K
96.5% HumanEval + 65K output for code-heavy agentic workflows
Best for: Coding agents (CI/CD, refactoring)
Input
$2/1M
Output
$16/1M
Context
200K
Max Output
66K
Input
$3/1M
Output
$15/1M
Context
200K
Max Output
16K
What Matters for Agents
Key Factors
- •Tool-use reliability
- •Reasoning ability
- •Max output
- •SWE-Bench
Tips
- ✓Tool-use reliability is the #1 factor — the model must call tools correctly
- ✓Claude Opus 4.6 and GPT-5.3 Codex lead in agentic benchmarks
- ✓Large max output prevents truncated tool-call sequences
Full Ranking (All Compatible Models)
| Rank | Model | Input | Output | Avg Bench | Score |
|---|---|---|---|---|---|
| #1 | GPT-5.3 CodexOpenAI | $2.00 | $16.00 | 88.2% | 152 |
| #2 | Claude Opus 4.6Anthropic | $5.00 | $25.00 | 86.7% | 137 |
| #3 | Gemini 3.1 ProGoogle | $2.00 | $12.00 | 93.4% | 129 |
| #4 | Gemini 3 ProGoogle | $2.00 | $12.00 | 86.9% | 128 |
| #5 | GPT-5.2 CodexOpenAI | $1.75 | $14.00 | 86.8% | 127 |
| #6 | Claude Sonnet 4.6Anthropic | $3.00 | $15.00 | 83.3% | 122 |
| #7 | GLM-5Zhipu AI | $1.00 | $3.20 | 77.8% | 121 |
| #8 | o3OpenAI | $0.40 | $1.60 | 86.9% | 121 |
| #9 | o4-miniOpenAI | $1.10 | $4.40 | 84.8% | 118 |
| #10 | Gemini 2.5 ProGoogle | $1.25 | $10.00 | 85.7% | 118 |
| #11 | Gemini 2.5 FlashGoogle | $0.15 | $0.60 | 82.8% | 116 |
| #12 | Gemini 3 FlashGoogle | $0.50 | $3.00 | 84.0% | 116 |
| #13 | GPT-5OpenAI | $1.25 | $10.00 | 85.7% | 104 |
| #14 | Mistral Large 3Mistral | $2.00 | $5.00 | 87.0% | 103 |
| #15 | Grok 4xAI | $3.00 | $15.00 | 83.7% | 101 |
| #16 | Claude Sonnet 4.5Anthropic | $3.00 | $15.00 | 81.9% | 96 |