A typeface tuned for AI text that streams in word by word
People read AI-generated text for long sessions, often while it is still streaming in. I wanted a typeface tuned for streamed prose at 13–16px.
I designed Seb Sans, a variable font derived from Inter, with an installer coding agents can run.
v0.7.2 ships 652 glyphs across 3 axes and 9 named weights.
AI answers are read while the text is still arriving.
Answers arrive a few words at a time, rewrap as they grow, and mix prose with code and tables. Type that works in a static mockup can feel unsteady in a live transcript.
Three requirements shaped the release: first, readable at 13–16px; second, an open license; and third, safe for agents to install.
People read AI answers for long sessions, and agents now install the fonts.
Spacing that is slightly off becomes tiring over a long transcript. Coding agents often install fonts now, so the install path mattered as much as the letterforms.
I tuned Seb Sans for long chat transcripts at reading size.
Start from Inter’s structure
I built on Inter’s open-source outlines and spent my time on rhythm, spacing, and weight for chat transcripts and summaries.
Instead of Drawing a new family from scratch.
Trade-off Seb Sans shares Inter’s structure, so it looks less distinctive at display sizes.
One variable file covers the whole weight range, shown here in six stops from 300 to 900. Tune spacing for streaming text
I set spacing and weights so lines keep their shape as new words arrive and the text rewraps.
Instead of Tuning for large marketing headlines, where most typefaces are judged.
Trade-off Large headlines need tighter manual tracking to look their best.
Set at reading size with a live caret. Lines should not jump when the next word arrives. Make installs safe for agents
Every install path runs without prompts and is safe to run twice. It also ships a typography skill that agents read to apply the right weights and line height.
Instead of A zip download and a README for humans.
Trade-off More engineering than a typical font release: a CLI, checksums, and a JSON manifest.
Numerals, punctuation, and symbols get the same attention as letters, since AI answers use them constantly.
Published on npm and used across this site.
- 652Glyphsv0.7.2 · measured
- 3Variable axesv0.7.2 · measured
- 13–16pxTuned UI rangedesign target · measured
Seb Sans is published as seb-sans-font under the OFL-1.1 license, with a specimen, installer, and agent manifest at /seb-sans.
Next: a matching monospace for code in AI answers.
AI answers switch between prose and code all the time. A matching monospace would make that switch less jarring.