The CLI locally runs a project which won't work on the platform

[honzajavorek]

When I have a JavaScript project and forget to specify the start script in package.json, I can successfully apify run the project locally and then successfully apify push and build the project, but then I get a cryptic error when trying to run the Actor:

There was an uncaught exception during the run of the Actor and it was not handled.

2025-07-28T14:12:31.302Z ACTOR: Pulling Docker image of build P3CRdkV2wuFmFapfp from registry.
2025-07-28T14:12:31.304Z ACTOR: Creating Docker container.
2025-07-28T14:12:31.443Z ACTOR: Starting Docker container.

That's all, no more logs, no other info about what went wrong. Took me a moment to debug this and figure out that I didn't specify npm start, so the platform doesn't know what to start and how. Which is logical, but the DX isn't great. I'd appreciate if apify run would fail fast or at least warn me about it. Apparently it can infer how to start the project, but then such behavior differs from what the platform requires.

[patrikbraborec]

Just for clarification, you first created a JavaScript project, and then added apify tooling (cli, sdks, etc.) manually, or did you run apify init?

[honzajavorek]

I had just an index.js file with a package.json, then I'm actorizing it by apify init, which creates the .actor directory. I made changes to code (npm i apify --save, await Actor.init() etc.) and then apify run to verify all is good. Then apify push.