For AI agents: the complete documentation index is available at https://flow.jig.md/llms.txt, the full documentation bundle is available at https://flow.jig.md/llms-full.txt, and this page is available as Markdown at https://flow.jig.md/guide/start.md.
FLOW
DocumentationGuidePrerelease

#Start building a Flow

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A Flow packages one reusable method so another consumer can understand and invoke it. Start with a small procedure whose input and useful result you can explain. The same boundary can later contain code, Agent judgment, or both; starting with code makes that boundary easy to see.

#Choose a concrete result

For a first method, use an echo or greeting to verify the exchange. Then replace its body with a useful operation, such as validating a supplied record or summarizing supplied text. Keep the operation's own checks in ordinary code.

The package contains FLOW.md and, for executable work, its implementation. Add resources and schemas when the method needs them. See Package/1 for the exact metadata and layout.

A description-only package can share readable guidance and resources. Without an implementation, it cannot itself execute a Run/1 invocation.

#Pick your authoring path

Your environmentFollow this path
TypeScript, running under JigCreate your first Flow. Jig initializes the package and pins the SDK revision paired with its build.
TypeScript, another compatible hostTypeScript SDK instructions. Check that the documented candidate version is published before installing it.
PythonPython SDK tutorial, including a local protocol exercise and expected output.

SDK availability and host language support are separate. A Python SDK does not establish that Jig can execute Python packages. The specifications and SDKs are prerelease; use the exact revision qualified by your chosen host.

#Recognize the exchange

A handler receives the invocation and returns an outcome with data. Choose your language to see the same method:

TypeScript
Python
flow.ts
import { handle } from "@jigging/flow";

await handle(async (run) => {
  return { outcome: "done", output: { received: run.input } };
});

With input {"name":"Ada"}, the method's result is {"outcome":"done","output":{"received":{"name":"Ada"}}}. The host may wrap that result with its own execution status and diagnostics.

These snippets define handlers; they are not standalone shell invocations. handle expects a Run/1 host exchange on stdin and stdout. Use the complete setup in your selected tutorial. Keep raw writes off protocol stdout; the SDK routes ordinary console diagnostics to stderr after handle starts.

#Make it yours

After the echo works, change the output to include a fixed greeting alongside received. Run it again and check both values. With Jig, review the source change before running the new revision.

Then choose the smallest useful method you want someone else to inherit. Document its purpose, inputs, outcomes, and limits in the package. Validate inputs before domain work and return a result whose meaning a consumer can check. A malformed input should have a deliberate, documented response.

#Build further