Custom steps

A step is a program. Kusaw sends it a request, it reports progress, and it ends with a result. Every step, built-in or custom, speaks the same step protocol. The built-in steps are defaults you can replace.

When to write a stepCopy Anchor Link

Write a custom step when you have something of your own to run:

• a check you already run
• a tool you trust
• your own agent prompt
• a different review

A config change is enough when you only need to adjust a default: its timeout, retries, fail_on, verification commands, or which MCP servers and skills it may use. You do not need a custom step to rename a timeout.

Built-in steps are defaultsCopy Anchor Link

builtin: <name> and command: [...] start the same way. Kusaw handshakes the program, sends the request, and reads progress and a result. Replacing the default review step, or the default build step, does not change gates, loops, or feedback as long as you keep the same step id.

In this sectionCopy Anchor Link

• Write your first step — handshake, request, progress, result, and a Python 3 worked example
• Replace a built-in step — point a pipeline entry at your command and keep the same id
• Use an agent inside your step — print or run the built-in provider argv with kusaw agent-args
• Ask the user: interactive turns — a turn step that asks the user questions with await_input, one per run
• More examples — the Python worked example, a checklist review, and the Go example
• Example pipelines — four complete pipeline shapes (loop, reviewer, planner) that call kusaw agent-args