Spellcheck in Claude Desktop (Ubuntu)

The short version

Claude Desktop is an Electron app, so it uses Chromium’s built-in spellchecker with its own
bundled Hunspell dictionaries. It does not read your system dictionaries, your LANG environment
variable, or your desktop locale settings.

There is currently no in-app setting to change the spellcheck language — it defaults to en-US.
Open feature requests:

• https://github.com/anthropics/claude-code/issues/72247
• https://github.com/anthropics/claude-code/issues/68621

Workaround: edit the Chromium Preferences file

The language is controlled by the spellcheck.dictionaries key in the app’s Preferences file.
The app rewrites this file on a clean exit, so the edit only sticks if the app is fully stopped
before you change it.

1. Fully quit the app

pkill -f -9 claude-desktop   # or: pkill -f -9 Claude

Verify nothing is left running:

pgrep -af -i claude

2. Locate the Preferences file

ls ~/.config/Claude/Preferences

The path can vary by install method. If it isn’t there, search for it:

find ~/.config ~/.var/app ~/snap -name Preferences -path '*laude*' 2>/dev/null

3. Back up and edit

cd ~/.config/Claude
cp Preferences Preferences.bak
 
jq '.spellcheck.dictionaries = ["pt-BR","en-US"]' Preferences > tmp && mv tmp Preferences

Install jq first if needed: sudo apt install jq

4. Restart Claude Desktop

Chromium downloads the dictionary on first use, so allow a few seconds before the underlines
correct themselves.

Language codes

Code	Language
pt-BR	Brazilian Portuguese
pt-PT	European Portuguese
en-US	US English
en-GB	British English

Listing more than one enables them simultaneously — useful if you mix Portuguese and English in the
same message. A word is only underlined if it’s missing from all the listed dictionaries.

Alternative: disable spellcheck entirely

In the same file:

jq '.browser.enable_spellchecking = false' Preferences > tmp && mv tmp Preferences

Troubleshooting

Symptom	Cause / fix
Edit reverts after restart	App wasn’t fully killed in step 1. Re-run pkill -f -9, confirm with pgrep.
No change after restart	Dictionary still downloading, or the app has no network access to fetch it.
jq reports a parse error	Wrong file. Confirm the path; restore with cp Preferences.bak Preferences.
Everything broke	cp Preferences.bak Preferences and restart.

Restore original settings

pkill -f -9 claude-desktop
cp ~/.config/Claude/Preferences.bak ~/.config/Claude/Preferences

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Note: this is an unofficial workaround that manipulates an internal Chromium config file. It may
stop working after an app update. Once the feature requests above are implemented, use the in-app
setting instead.