write-flow

Create and validate Windmill flow definitions using the wmill CLI and OpenFlow schema.

Updated May 28, 2026
One-click install
npx skills add https://github.com/kma-core/windmill --skill write-flow-kma-core
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: write-flow
Source: https://github.com/kma-core/windmill/tree/main/system_prompts/auto-generated/skills/write-flow
Command: npx skills add https://github.com/kma-core/windmill --skill write-flow-kma-core

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve? Building Windmill flows by hand leads to structural errors like misplaced preprocessor modules, missing input transforms, and invalid result references. This Skill guides the AI agent to scaffold flows correctly with the wmill CLI and author valid flow.yaml definitions that conform to the OpenFlow schema. ## Core Features & Use Cases - CLI-Based Scaffolding: Runs wmill flow new with the correct path and summary flags so the folder suffix and flow.yaml shell match workspace settings. - OpenFlow Schema Guidance: Enforces structural rules for modules, loops, branches, approval steps, preprocessor and failure handlers, and input transforms. - Preview and Deploy Workflow: Distinguishes wmill flow preview for local iteration from wmill flow run and wmill sync push for deployed execution. - Use Case: A developer asks to build a flow that fetches data, loops until a condition is met, and requests approval. The Skill scaffolds the flow, writes a valid whileloopflow with module-level stop_after_if, adds a suspend step, and previews it locally. ## Quick Start Ask the agent to create a new Windmill flow at a given path with a short summary, then let it scaffold, fill in flow.yaml, and preview the result.

Frequently Asked Questions about write-flow

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I create a new Windmill flow from the CLI?

Run `wmill flow new <path> --summary "description"` to scaffold the flow folder with the correct suffix and a minimal flow.yaml. Then edit the generated flow.yaml to add real modules and schema before previewing with `wmill flow preview`.

How do I test a Windmill flow without deploying it?

Use `wmill flow preview <flow_path>` to run the local flow.yaml against local inline scripts without deploying. Add `--step <step_id>` to run a single module in isolation, or `--remote` to use deployed workspace scripts for PathScript steps.

Where do preprocessor and failure handlers go in a Windmill flow?

They belong in `value.preprocessor_module` and `value.failure_module` as special top-level fields, not as entries in `value.modules`. Both only support script or rawscript types, and the preprocessor cannot reference other step results.

Why is my Windmill rawscript step receiving empty inputs?

Rawscript modules require `input_transforms` to map function parameters to values. Use a static transform for fixed values or a javascript transform with expressions like `results.previous_step` or `flow_input.property`.

Can I reference branch step results outside a branchone in Windmill?

No, steps inside branchone or branchall branches are not in scope outside the branch. Reference `results.<branch_module_id>` instead, and add a normalization step after the branch if downstream steps need a stable shape.

When should I use wmill sync push versus flow preview?

Use `wmill flow preview` while iterating on local flow.yaml edits since it does not deploy. Reserve `wmill sync push` for when you explicitly want to publish validated changes to the workspace, since pushing overwrites the deployed version.