Mephisto 3.1.205 — four-player game-mode detection

Four-player chess reads the game mode now. Plus an eval bar that could freeze.

Which download?

Archive	Size	Use it when
mephisto-3.1.205.zip	585 MB	First install — everything, engines included
mephisto-3.1.205-update.zip	5.9 MB	You already have Mephisto — extract over your existing folder

⚠️ Extract the update over your existing install, never into an empty folder — without the engines it cannot run. Extract in place, too: Chrome derives an unpacked extension's id from its folder path, so a new folder means a new id and re-running the native-host installer.

Teams vs free-for-all

Tetrarch implements Teams only — its free-for-all search does not exist — and the panel was telling it Mode: teams for every board. On an FFA game that yields a confident move scored under rules nobody at the table is playing. The scraper now works out the mode and sends it with the position, and an FFA board says so rather than analysing.

Detection reads the URL first, then the mode wording on the page. The per-seat points display that would separate the two structurally is unverified, so the default stays Teams and every signal it considered is logged — one real FFA game will pin it rather than a second guess.

The eval bar could freeze

The native host returns a bare {move, pv} when a search produces no info line. score was then undefined, the win-percentage curve came out NaN, and height: NaN% left the bar wherever it happened to be — which reads as an eval bar that does not move. A scoreless line is now ignored instead of poisoning the bar.

Coming: Chess.com puzzles

Once the upstream pull request is merged, a database of 620,000+ Chess.com puzzles with their solutions will be published for import the same way as the Lichess one — same settings page, same import button, and on a hit the panel plays the known line with no search at all.

Everything else is unchanged from 3.1.204.