Last summer I wrote up Octopus Agile Prices For Linux, a small GTK app to show the current Octopus Agile electricity price and the next day of half-hourly rates. It did one thing, which is a good number of things for a desktop utility to do.

Since then the app has become a bit less narrow. But it now does enough more that the launch post undersells it, and in a couple of places sends people looking for the wrong name.

The app is now called Agile Rates. The application ID is still com.nedrichards.octopusagile, because changing stable app IDs is not exciting for anyone, but the name changed because Agile is no longer the whole story. Thanks to code from Andy Piper, it can also work with Octopus Go and Intelligent Go tariffs. Intelligent Go needs an API key because those prices are account-specific, but plain Agile and Go can still be set up manually.

That was the first larger change: setup had to become a thing.

The original app assumed you knew your tariff and region, or at least were willing to rummage in preferences until the graph stopped being wrong. That is fine for a scratch-your-own-itch project and a bit rude for an app on Flathub. The current version opens with a setup assistant. You can connect an Octopus account with an API key and account number, in which case the app tries to detect the active electricity tariff. Or you can keep it simple and choose the tariff and region manually.

The second change is the one I actually use most: finding the cheapest slot.

The launch version showed a graph and left the planning to the human. That works for quick glances, but most of my real questions are more specific:

When should the dishwasher run?
When should the washing machine run?
Is there a cheap three-hour block before tomorrow afternoon?

So there is now a “find cheapest time” tool. Pick a duration and it searches the available forecast window for the cheapest continuous block. Later I added the average price for that block as well, because total cost is useful but average unit price is how my brain checks whether the answer feels plausible. The chart now scrolls to the chosen time instead of making you squint along the bars like you are reading a very dull railway timetable.

The graph itself has had a lot of quiet work. It has grid lines, clearer day boundaries, better current-price highlighting, less terrible dark-mode contrast, and layout rules that behave on narrower screens. The preferences window and main window are adaptive now too. Handy if you split your screen or have a Linux phone.

The biggest recent addition is usage history. If you connect an account, the app can fetch recent smart meter consumption data, cache it locally, and show a Usage view. That includes kWh history, a seven-day trend, an estimated monthly usage figure, and charts. It also tries to estimate spend by matching historical usage to tariff rates and standing charges.

The app can only calculate what the API and the cached data allow it to calculate. It fetches consumption pages, works out the relevant tariff periods from the account data, then looks up historical unit rates and standing charges. When it has complete data it says so. When it has to fall back to averages it says that too. I would rather the app be slightly fussy about confidence than present a made-up precision to two decimal places and hope nobody notices.

Underneath that, the project has become more like a real small application. There are unit tests for pricing, tariff selection, adaptive layout, usage insights, and historical cost calculation. The development Flatpak manifest runs the Meson tests inside the GNOME SDK, which catches the class of bugs where the host Python environment was accidentally being too kind. Ruff is in the loop for linting. The app moved to the GNOME 50 runtime. Screenshots, AppStream metadata, branding colours, and icons have all been tidied up.

So the current honest description is: Agile Rates is a small GNOME app for UK Octopus Energy customers who want current and upcoming smart tariff rates, a cheap-time finder, and, if they connect their account, recent usage and estimated spend history. It is independent and is not affiliated with, endorsed by, or sponsored by Octopus Energy.

The old launch post can stay as the origin story, but it is no longer the whole story. What started as “show me the next 24 hours of Agile prices” has become “help me make a small domestic electricity decision without opening a browser”. That is still a narrow job, which is why I like it. It just has a few more of the useful bits attached now.