Step 5 Preview via the Tokenator API
What the model is for
Step 5 Preview is StepFun's flagship model for agentic work, built on a sparse Mixture-of-Experts architecture (27B active / 600B total parameters). It performs strongly in software engineering and professional knowledge work, with particular strength in finance. It is designed for extended tasks that span large codebases and documents, using tools and refining results over multiple steps.
Specification
| Full name | Step 5 Preview |
| API ID | step-5-preview |
| Model vendor | StepFun |
| Type | Text model (chat / completions) |
| Context window | 1.05M tokens |
| Max output | 131.1K tokens |
| Image input | yes |
| Tokenator usage multiplier | 1.2× |
| Input modalities | text, image |
| Aliases | cursor-step-5-preview |
| Supported API formats | /v1/chat/completions /v1/responses /v1/messages |
| Upstream providers | 1 |
| Current status | available |
| Data updated | 2026-11-02 |
Benchmarks
| Intelligence index | 28.5 |
Artificial Analysis data loaded into the catalog for this model.
Upstream providers
| Provider | Multiplier |
|---|---|
| AiPartners Ltd | 1.2× |
A request goes to the first available provider by priority; if it fails, Tokenator switches to the next one.
Example request
curl https://api.tokenator.top/v1/chat/completions \ -H "Authorization: Bearer sk-your-tokenator-key" \ -H "Content-Type: application/json" \ -d '{ "model": "step-5-preview", "messages": [{"role": "user", "content": "Hello"}] }'
Compatible tools
The model can be used in any tool that accepts a custom base URL: Claude Code, Codex CLI, OpenCode, Cursor, Cline, Kilo Code, Cherry Studio, DeepSeek Harness, Hermes, Pi, OpenClaw.
See also
FAQ about Step 5 Preview
What is the API ID of Step 5 Preview?
step-5-preview — put this into the model field of your request.
What context window does Step 5 Preview have?
1.05M tokens; max output is 131.1K tokens.
How many tokens will a request cost?
(input + output) × 1.2×. See the documentation for details.
Which tools support this model?
Any tool that accepts a custom base URL: Claude Code, Codex CLI, OpenCode, Cursor, Cline, Kilo Code. Setup guides are in the integrations section.