Migrating from diffle

nittle used to be called diffle. The rename changed the command, the data directory, the plugin names and the environment variables. You don’t have to do any of it by hand: the first time you run nittle, it migrates everything in one pass and then removes the diffle leftovers.

Installs from the loupe era are migrated too, so the same applies if you skipped diffle.

What the first run moves

• The data directory. ~/.diffle moves to ~/.nittle, review records included. Nothing is deleted until it’s confirmed at the new location.
• The install. The binary directory moves from ~/.diffle/bin to ~/.nittle/bin, and the old PATH entry is swapped for the new one.
• Agent plugins and MCP configs. The diffle-review plugin becomes nittle-review, and any diffle MCP server entry in your agents’ configs is renamed to nittle.
• Browser preferences. Settings stored under diffle-* keys are carried over to nittle-*.

In your shell profile, nittle touches only the old installer’s own # >>> diffle >>> block. It rewrites that block to the nittle one, after backing the file up, and leaves every other line alone. If something can’t be moved, nittle keeps both copies, prints exactly what is left, and tries again on the next run.

Environment variables

DIFFLE_* variables are still read as a fallback, and nittle prints a one-time notice asking you to rename them. Use NITTLE_* going forward. LOUPE_* variables are no longer read.

After the first run

There is no diffle command anymore, so update scripts and aliases to call nittle. Start a new agent session (or run /reload-plugins in Claude Code) so the nittle MCP server replaces the old one.

If a leftover plugin survives, nittle doctor finds it and nittle doctor --fix repairs it. To install fresh instead, see Installation.