Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx skills add glebis/claude-skills --skill font-featuresgit clone --depth 1 https://github.com/glebis/claude-skillsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/glebis/claude-skills/font-features)<a href="https://agentmods.dev/skills/glebis/claude-skills/font-features"><img src="https://agentmods.dev/badge/skills/glebis/claude-skills/font-features/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/glebis/claude-skills/font-features"><img src="https://agentmods.dev/badge/skills/glebis/claude-skills/font-features.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00129 | $0.00853 |
| Opus 5 | $0.00064 | $0.00426 |
| Sonnet 5 | $0.00026 | $0.00171 |
| Haiku 4.5 | $0.00013 | $0.00085 |
Grade A, and why
font-features scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 44 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Font Features (OpenType → CSS)
Inspect a font's real OpenType feature inventory and generate CSS to enable chosen features. Never guess what a font supports — always run scripts/otfeat.py list first; only features present in the dump may be offered or enabled.
Requires fontTools (pip install fonttools if missing).
Workflow
-
Inspect the actual font files in the project:
python3 <skill-dir>/scripts/otfeat.py list path/to/Font-Regular.woff2 [more fonts...]Output lists each font's GSUB/GPOS tags with human descriptions (Monaspace stylistic sets are described precisely; unknown
cvXXare labelled generically). -
Interview the user via cenno (
mcp__cenno__ask_user, orask_sequencefor several questions). Offer ONLY features found in step 1, grouped sensibly, with a recommendation. Typical question set:- Coding ligatures: which sets? (arrows ss03, colons ss07, comparison ss02...) — for code samples only, usually off for prose
- Numerals: tabular (
tnum) for tables/timers, oldstyle (onum) for prose, slashed zero (zero) - Texture healing (
calt) — for Monaspace, recommend ON everywhere - Caps:
casefor uppercase labels/buttons,smcpif present Useinput: {kind: "choice"}with a text option, mark optional questions low-urgency, and respect a "skip" answer.
-
Generate CSS deterministically:
python3 <skill-dir>/scripts/otfeat.py css --family "Monaspace Neon" \ --features calt,liga,tnum,case --class prose # cvXX with a value: --features cv01=2High-level
font-variant-*properties are preferred automatically (they cascade and combine better); remaining tags fall back tofont-feature-settings.--no-variant-propsforces the low-level form only. -
Apply: paste the block into the project stylesheet; scope per element role (e.g.
tnumon tables/stat tiles only, ligature sets oncodeonly). Verify in a browser with real content.
Gotchas
font-feature-settingsis all-or-nothing per declaration — a second declaration on a nested element REPLACES the inherited list; repeat the full list. This is the main reason to preferfont-variant-*.- CSS accepts any tag, browsers silently ignore ones the font lacks — which is why step 1 is mandatory (e.g. Monaspace has NO
tnum/zero/smcp; it's a monospace family and zero is already slashed). - Stylistic-set meanings are font-specific; never reuse Monaspace's ss-descriptions for another family.
- A feature tag being present does not mean it covers the glyphs assumed: dump the actual GSUB substitutions before writing demo copy (e.g. Monaspace's
caseonly raises: ¡ ¿ ‽and combining accents — NOT quotes, brackets, or dashes). - Texture healing needs
caltAND ligatures left enabled;font-variant-ligatures: nonekills it.
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 10d ago First seen · 44 lines · 129 tokens per session scan A 7d11594ced44
font-features is a skill published in the GitHub repository glebis/claude-skills (374 stars, last pushed 7d ago), licensed MIT. It adds 129 tokens to every session and 853 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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