Step library
A step is one entry in a workflow's step_configs. Each step names an activity — the unit of work Jetty knows how to run — plus the config that activity needs. For how steps chain together and pass data, see workflows & steps. This page is the catalog of activities you can reach for.
Activities fall into four families: AI models, control flow, data processing, and evaluation. The tables below list a representative slice of each, not the whole registry.
AI models
These call language, image, and video models. Each family needs the matching provider key configured; see runtimes and the connected-accounts idea for how Jetty resolves credentials at run time.
| Category | Activity | What it does |
|---|---|---|
| AI models | litellm_chat | One chat completion against any of 100+ providers via LiteLLM. |
| AI models | litellm_batch | Many completions in one step: fan out a list of requests. |
| AI models | Gemini steps | Prompt and reader activities plus gemini_image_generator. |
| AI models | AWS Bedrock | Invoke models hosted on Bedrock. |
| AI models | replicate_text2image | Replicate models for text-to-image and the rest of the Replicate catalog. |
Control flow
These shape how a workflow runs: branching, looping, fanning out across many inputs, and pulling data back out of prior runs.
| Category | Activity | What it does |
|---|---|---|
| Control flow | list_emit_await | Fan out over a list and run children in parallel. |
| Control flow | conditional_branch | Take one path or another based on a value. |
| Control flow | number_sequence_generator | Produce a numeric range to iterate over. |
| Control flow | loop_counter | Track iterations in a loop. |
| Control flow | extract_from_trajectories | Pull values out of earlier trajectories into the current run. |
Data processing
The glue steps: moving text and files around, attaching metadata, and reaching out over HTTP.
| Category | Activity | What it does |
|---|---|---|
| Data processing | text_concatenate | Join text fragments into one string. |
| Data processing | read / download / save file steps | Read, fetch, and persist files through Jetty storage. |
| Data processing | metadata | Attach or read metadata on an asset. |
| Data processing | webhook | Call out to an external HTTP endpoint mid-workflow. |
Evaluation
These grade and analyze runs, the steps that drive trajectory-based evaluation.
| Category | Activity | What it does |
|---|---|---|
| Evaluation | simple_judge | LLM-as-judge: score on a 1–5 scale or a categorical rubric. |
| Evaluation | select_trajectories | Filter prior trajectories into a set to analyze. |
| Evaluation | visualize_correlation | Plot how scores or signals relate across runs. |
Discovering steps programmatically
This catalog is a snapshot, while the live registry is the source of truth. List the full set of step templates from your editor with list-step-templates (MCP) or listStepTemplates (SDK), then inspect any one to see its exact config shape.
Ready to wire these together? See examples & recipes for copy-paste workflow JSON.