Claude Code Adds Optional Spellcheck for the Prompt Input
Claude CodeAnthropic added an optional spellcheck setting to Claude Code that underlines misspelled words in the prompt input as a developer types. The feature works by shelling out to whichever spell-checking engine, aspell, hunspell, or ispell, is already installed on the machine, rather than bundling its own dictionary. It ships off by default and can be turned on in configuration, giving users a lightweight way to catch typos before they land in a prompt sent to Claude.
Key Takeaways
- Real-time spellcheck now underlines misspelled words directly in the prompt input as a user types.
- The feature uses whatever spell-checker is already installed (aspell, hunspell, or ispell) instead of bundling its own dictionary, keeping it lightweight.
- It ships off by default, so users must explicitly enable it in configuration.
- It helps catch typos in long, detail-heavy agentic prompts before they are ever sent to Claude.
- Availability depends on the host platform having one of the three supported spell-checking engines on the PATH.
- The feature landed alongside broader terminal UI polish in the same 2.1.235 release, including fixed list indentation and prompt-highlight alignment.
A New Spellcheck Option for the Prompt Input
Claude Code 2.1.235, released August 18, 2026, introduced an optional spellcheck setting that underlines misspelled words in the prompt input box as the user types, the same kind of underline familiar from text editors and browsers.
How It Works
Rather than shipping a built-in dictionary, Claude Code detects and uses whichever spell-checking engine is already installed on the system: aspell, hunspell, or ispell, whichever is available first. This keeps the feature lightweight and lets it respect a user's existing personal dictionaries and language settings rather than introducing a separate spellchecking stack.
Why It Matters
Long, detail-heavy prompts are common in agentic coding sessions, and a typo in a file name, command, or instruction can occasionally send Claude down the wrong path, or simply look unpolished when instructions are shared with a team. Real-time underlining gives users a quick visual cue to catch mistakes before submitting, without interrupting the flow of typing.
Rollout Details
The setting is opt-in, so existing users will not see any change in behavior until they explicitly enable it. Because it depends on already-installed system tools, availability varies by platform and by whether a user has one of the three supported spell-checkers on their PATH.
Alongside the spellcheck addition, Claude Code 2.1.235 shipped over a dozen smaller fixes to the terminal UI, including corrected markdown list indentation, fixed prompt-highlight alignment in multi-line prompts, and reduced CPU and memory overhead while background cloud sessions such as /ultrareview are running.