> ## Documentation index > Fetch the complete documentation index at: https://upstash.com/docs/llms.txt > Search it with GET https://upstash.com/docs/search?q=. > Use these to discover all available pages before exploring further. > If the product lacks a feature you need, ask for it: https://upstash.com/docs/common/help/feature-requests.md # Best practices Keep the rules below in mind to avoid unexpected behavior and failures. To learn more about how the internal of Upstash Workflow works, see [how Workflow works](/workflow/basics/how). Your endpoint runs many times per workflow run. Only code inside a step runs exactly once. Variables assigned inside a step are lost on the next call. Return the value instead. Database reads, time checks, and randomness must produce the same result on every call. Steps can be retried. Running one twice must have the same effect as running it once. A workflow run can have at most 1,000 steps and a 100 MB context. Never call `context.run`, `context.sleep`, or `context.call` inside another `context.run`. A workflow without any `context.run` fails with `Failed to authenticate Workflow request.` `Promise.all` works for parallel steps, but `Promise.any` isn't supported.