Step 5 Preview is StepFun's 600B sparse MoE frontier model for production-scale agents, activating 27B parameters per token. It is built for software engineering, long-horizon tool use, research, professional knowledge work, and finance, with native text, image, and video understanding and a 1M-token context window. ⚠️ Note: This model routes through StepFun, so privacy and logging guarantees may be limited.
Added Sep 20, 2026
Context Window
1.0M
Max Output
1.0M
Avg output tokens (7d)
1.8K tokens
Input Price (Auto)
$1.00/1M
Output Price (Auto)
$2.70/1M
Cache Read (Auto)
$0.050/1M
Capabilities
Benchmarks
Benchmarks
Performance metrics and benchmarks
Sourced from Artificial Analysis.
Intelligence Index
43.7
Agentic work
AutomationBench-AA
Workflow automation with guardrail penalties
51.0%
Better than 67% of models compared
AutomationBench-AA Tasks Completed
Fully completed workflows without guardrail violations
17.7%
Better than 23% of models compared
Harvey LAB-AA
Legal agentic work criterion pass rate
93.4%
Better than 89% of models compared
AA-Briefcase
Agentic knowledge work (Elo)
1432 Elo
Better than 79% of models compared
GDPval-AA v2
Economically valuable tasks (Elo)
1566 Elo
Better than 88% of models compared
Document reasoning
GDP.pdf
Professional PDF reasoning: all-pass rate
14.8%
Better than 56% of models compared
AA-LCR v1.1
Long context reasoning with updated grading
88.3%
Better than 99% of models compared
MLCR-AA
Medical long-context reasoning
16.7%
Better than 56% of models compared
Reasoning
HLE
Humanity's Last Exam
46.5%
Better than 94% of models compared
Coding
Terminal-Bench v4.0
Practical coding and terminal tasks
33.3%
Better than 83% of models compared
SciCode
Python programming for scientific computing
58.9%
Better than 93% of models compared
Legacy benchmarks
AA-LCR (unversioned / legacy)
Long context reasoning evaluation
88.3%
Better than 99% of models compared
Last updated Oct 1, 2026
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