Used electric cars · Finland · v1
A decision tool, not a calculator
carguide runs the used-EV comparison on your own machine, driven by the Claude or Codex subscription you already pay for. Every figure carries the source it came from, and a gate refuses the ones that have drifted away from it.
Example output
Ask your agent to rank the shortlist. It answers with cost per month over five years, and every row says where its numbers came from.
| Car | Price | Retained | Cost / month | Price basis | Faults |
|---|---|---|---|---|---|
| 1 Tesla Model 3 RWD, 2023 | 29 900 € | 54 % | 612 € | listed 2.9 | none open |
| 2 Polestar 2 LR Single, 2022 | 28 400 € | 51 % | 631 € | listed 2.9 | 1 campaign |
| 3 Kia EV6 77 kWh, 2022 | 31 500 € | 52 % | 668 € | quoted 21.8 | 1 campaign |
| 4 Hyundai Ioniq 5 73 kWh, 2022 | 30 900 € | 50 % | 679 € | listed 1.9 | none open |
| 5 Volvo EX30 ER, 2024 | 33 200 € | 55 % | 702 € | offer expired | 2 campaigns |
Every figure in the model carries a basis like these. The ones you see here are the same chips the tool prints, on example rows.
Why the spreadsheet lies
Two losses sit at the end of a bad comparison. You pay thousands over the market. Or you buy a car with a fault nobody put in the advert.
You guess the insurance and the servicing. The real quotes come back higher. In this project's own model every guessed premium sat below the quote, and every error favoured the car the owner already wanted.
A dealer offer expires. A price moves and the residual behind it does not follow. The cell still holds a number, so nothing looks wrong.
“No problems found” and “the check never ran” print the same. carguide reports what it looked at beside what it found, so an empty result cannot pass as a pass.
Four steps to a first ranking
STEP 1
One file for Claude Desktop, or one line of config for Claude Code and Codex. Nothing runs in the cloud.
STEP 2
Your decision lives there as plain text you can read, edit and keep. Delete the folder and nothing of it remains anywhere else.
STEP 3
Paste a listing, ask for the ranking, ask why. The agent calls the tool; the tool does the arithmetic and the checking.
STEP 4
Five documents: what to buy, what it costs, what to check on this car, what to do at the kerb, and one table of everything.
Eight checks
Ask for a check and the tool tests the model against the sources it cites, then against itself. It reports the count it examined next to the count it rejected.
sources
Every specification figure must equal the catalogue entry the row cites, or state in writing why it differs.
plausible
Figures that are believable alone and wrong together. A charging peak too high for the battery behind it, a boot smaller folded than upright.
faults
Every car needs a researched fault section, and every campaign number must exist in the Finnish or the American register.
attributes
A quoted offer carries the date it dies. An expired price ranked beside live ones is an error, not a rounding difference.
reviews
Three magazines, three scales, kept apart and never averaged. A score must match the page it was read from.
reports
Every table in the documents must equal what the model produces right now. Drift is named row by row, and never repaired behind your back.
wellformed
The documents stay readable offline: no missing columns, no images borrowed from someone else's server.
coverage
The number of figures under watch cannot fall without you approving the fall. Deleting a check is not a way to pass one.
Ten things to ask it
Three clients, one binary
carguide adds tools to your assistant. It does not replace it, and it has no chat window of its own.
One-click install. Ranked tables appear in the conversation.
macOS · Windows
Installs as a plugin, with the buying method included as a skill.
terminal
One entry in your config file. The same tools, the same folder.
CLI · IDE · desktop
Your listings, prices and notes stay in your folder. The tool talks to car catalogues and the two public recall registers, and never to us.
Five limits
It covers Finland in this version. The catalogues and registers it reads are Finnish, German and American.
It reads asking prices, which are an upper bound. Nobody publishes what cars actually sold for.
It never contacts a seller, makes an offer, or signs anything. Every irreversible step stays yours.
It has no opinion on how a car feels to drive. It ranks cost, faults and fit, and says so.
Every figure is anchored to the day it was read. Re-run the check before you travel to see a car.
Price and availability
Sold to a small first group while the tool proves itself on real purchases. You bring your own Claude or Codex subscription; we sell the method, not the model.