claude-bionify

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claude-bionify bolds the leading part of each word in Claude's streamed replies, giving your eye a fixation point per word. This is the bionic-reading technique, inspired by the eye-movement research showing that we read by fixating a single convenient position toward the start of each word, where its opening letters carry the most information for recognising it (Rayner, 1979; O'Regan et al., 1984).

It only changes how text looks on screen. What gets saved to the transcript and what Claude reads stays the original, unbolded text, which you can reopen any time with the Ctrl+O transcript view.

Features

• ⚡ Faster, calmer reading. Fixation points pull your eye word to word through long answers.
• 🌍 Any language. Unicode-aware, so accents and non-Latin scripts bold correctly, not just English.
• 🎚️ Three boundary modes. fraction, syllable, or log — see Configure.
• 🧩 Markup-aware. Code, links, URLs, paths, and acronyms stay intact (what it touches).
• 🔒 Private, zero-dependency. Nothing to install, no network, no telemetry — it runs entirely on your machine.
• 🪶 Crash-safe. On any error it falls back to the original text.

Install

/plugin marketplace add abullard1/claude-bionify
/plugin install claude-bionify@claude-bionify

claude-bionify is active right away. Turn it off or back on any time with /claude-bionify:off and /claude-bionify:on, or from /plugin.

Configure

When you enable the plugin, Claude Code prompts for these (all optional):

Setting	Default	Meaning
Bold boundary	fraction	fraction bolds by Fixation strength; syllable ends each word at its first syllable (e.g. string); log grows logarithmically so long words are bolded less.
Fixation strength	0.5	Fraction of each word to bold (0.1–0.9). Higher is bolder. Applies to fraction mode only.
Minimum word length	4	Words shorter than this are left unbolded.
Skip acronyms	on	Leave ALL-CAPS acronyms like API or JSON whole.
Protect URLs, paths, files	on	Don't bold inside URLs, emails, file paths, or filenames.
Skip headings	on	Leave markdown headings (# lines) unbolded; they're already prominent.

Control it live

Change claude-bionify mid-session without a reload or any config editing. The next reply reflects it right away:

Command	Does
/claude-bionify:toggle	Flip claude-bionify on/off
/claude-bionify:on · /claude-bionify:off	Turn it on or off explicitly
/claude-bionify:set strength 0.7	Set fixation strength (0.1–0.9)
/claude-bionify:set boundary syllable	Switch boundary (fraction · syllable · log)
/claude-bionify:set minlen 5 · /claude-bionify:set acronyms off · /claude-bionify:set urls off · /claude-bionify:set headings off	Tweak the other settings
/claude-bionify:status	Show the active overrides
/claude-bionify:reset	Clear overrides, back to your configured defaults

These write a small override file that the hook reads on every message, so changes take effect immediately and persist until you reset.

Themes

claude-bionify also ships seven color palettes for Claude Code's /theme picker (custom:claude-bionify:<name>). They retint Claude Code's interface and are independent of the bolding.

Exact palette values