How expensive are the API charges? Seems like it might be a bit too easy for a customer to rack up a big bill testing out minor changes if things weren't configured correctly.
Literally free. No API - the reason I went for Jules instead of Claude Code / Gemini CLI for example is specifically because of it's relatively polished web-interface, which I assumed that my customer would appreciate. They're using their own Google account and the daily tasks free limit seem to be more than enough for them.
There is a free plan with 15 tasks/sessions. It doesn’t count tokens AFAIK. There would obviously be a runtime limit of some sorts for sure. But it’s not the same as API keys and token situation
The free tier is 15 tasks per day (of gemini-2.5-pro) which is EXTREMELY generous. I've had plenty of tasks run for 1-2 hours. I do think that after 1 or 2 hours it's told it needs to wrap up and just present what it's done; I couldn't get it to keep going longer than 2 hours. But Jules is very slow as it seems to be batch processing on spare capacity, so 15+ hours a day is not quite as absurd as it sounds.
I haven't tried Jules in a couple weeks, but the UI/UX had a lot of issues such as not being given any progress updates for very long times. The worst thing was not being able to see what it was doing and correct it: you only see the state of files (without a usable diff viewer, WTF) at the last point that the agent decided to show you anything (the last time it completed a todo list item I think, and I couldn't get it to update the state when asked, though it will send a PR if you ask), and gemini-2.5-pro can often try really stupid things as it tries to debug. I've also been impressed at its debugging abilities a number of times.
Still, I found Jules far more usable than Gemini CLI (free tier), where Gemini just constantly stops for no reason and needs to be told to continue, and I exhausted the usage limit in minutes.
Aside from the unlimited free tier, probably the best part of Jules are its automated code reviews. Once, I was writing up some extensive comments on its code and then unexpectedly a code review was dropped in the conversation which gave exactly the same feedback I was writing. Unfortunately if it never reaches the point of submitting for review, it doesn't get an automated review. It does often ask for feedback before it's done, which is nice. So probably I needed to prompt better.