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 Dragoon0x/canon --skill canon-fonts-loadinggit clone --depth 1 https://github.com/Dragoon0x/canonWrote 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/dragoon0x/canon/canon-fonts-loading)<a href="https://agentmods.dev/skills/dragoon0x/canon/canon-fonts-loading"><img src="https://agentmods.dev/badge/skills/dragoon0x/canon/canon-fonts-loading/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/dragoon0x/canon/canon-fonts-loading"><img src="https://agentmods.dev/badge/skills/dragoon0x/canon/canon-fonts-loading.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00073 | $0.00982 |
| Opus 5.5 | $0.00029 | $0.00393 |
| Sonnet 5.5 | $0.00015 | $0.00196 |
| Haiku 4.5 | $0.00007 | $0.00098 |
Grade A, and why
canon-fonts-loading 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 2mo 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 — 106 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CANON · Font Loading
Fonts block rendering by default. Control the loading strategy or the browser controls it for you, badly.
font-display — always declare it
@font-face {
font-family: 'Geist';
src: url('geist.woff2') format('woff2');
font-display: swap;
}
| Value | Behavior | Use |
|---|---|---|
swap |
Show fallback immediately, swap when loaded | Default for body text |
optional |
Show fallback; use custom font only if already cached | Performance-critical pages |
block |
Invisible text for up to 3s | Never for body; acceptable for icon fonts |
fallback |
100ms invisible, then fallback, swap if loaded within 3s | Good middle ground |
font-display: swap is the CANON default. optional for ultra-fast pages.
Preload critical fonts
<link rel="preload" href="/fonts/geist-regular.woff2" as="font" type="font/woff2" crossorigin>
Preload only the critical weight (regular body text). Don't preload every weight — that defeats the purpose.
Limit font families and weights
| Budget | Reason |
|---|---|
| 1–2 font families | Visual consistency, reduced HTTP requests |
| 2–3 weights per family | Most UIs need regular + medium + bold at most |
| Total font files ≤ 4–6 | Each file is a blocking or swap-flashing resource |
Variable fonts reduce file count: one file covers all weights.
WOFF2 only
WOFF2 is supported by every modern browser and is 30% smaller than WOFF. Don't serve TTF, OTF, or WOFF to browsers — WOFF2 only (with WOFF fallback if you must support very old browsers).
Subsetting
If you only use Latin characters, subset the font to remove CJK, Cyrillic, etc. Tools: pyftsubset, Google Fonts &subset=latin, glyphhanger.
A full Noto Sans is 20MB. Latin-subset is 20KB. Subsetting matters.
Reducing FOUT (Flash of Unstyled Text)
- Match the fallback font's metrics to the custom font:
size-adjust,ascent-override,descent-override. - Tool:
fontainegenerates these values automatically.
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.
- 2mo ago First seen · 106 lines · 73 tokens per session scan A ae285cb30f4c
canon-fonts-loading is a skill published in the GitHub repository Dragoon0x/canon (6 stars, last pushed 6mo ago), licensed MIT. It adds 73 tokens to every session and 982 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-08-31.
canon-fonts-loading compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| canon-fonts-loadingDragoon0x/canon | Skill | 6 | 6mo ago | MIT | A | 73 | Claude Code, Codex |
| accessibilityericrisco/rsc-harness | Skill | 503 | 2d ago | MIT | A | 86 | Claude Code, Codex |
| accessibility-auditNickCrew/Claude-Cortex | Skill | 66 | 4mo ago | MIT | A | 31 | Claude Code, Codex |
| swiftui-layout-componentsdpearson2699/swift-ios-skills | Skill | 1.3k | 3mo ago | none | A | 101 | Claude Code |
| color-contrast-auditorcuriositech/windags-skills | Skill | 18 | 6d ago | none | A | 117 | Claude Code |
| accessibilitydiegosouzapw/awesome-omni-skills | Skill | 170 | 4mo ago | MIT | C | 119 | Claude Code, Codex |
| lagannOldiiik/Design-Lagann | Skill | 2 | 18d ago | none | A | 0 | Claude Code, Codex |