font-engineer

font-engineer is an agent for Claude Code from eduairet/claude-font-proofer. It costs 100 tokens per session (802 once invoked), scanned A, original, MIT.

A specialist for working with digital fonts and producing print-ready proof PDFs. It examines font features, shapes text correctly for different writing systems, and renders the proof through a containerized setup.

In plain words
What is it for?
Use it to inspect fonts, test OpenType features such as ligatures and kerning, render multilingual specimens, and maintain the scripts, templates, and container used to create the PDF.
Why use it?
It keeps font inspection and rendering grounded in the actual font files while separating technical output from editorial decisions and protecting the user's font files from changes.

Agent for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it to inspect fonts, test OpenType features such as ligatures and kerning, render multilingual specimens, and maintain the scripts, templates, and container used to create the PDF.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/eduairet/claude-font-proofer/font-engineer
Install

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.

Clone the repo
git clone --depth 1 https://github.com/eduairet/claude-font-proofer

Made for: Claude Code.

Wrote 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.

agentmods badge for font-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/eduairet/claude-font-proofer/font-engineer.svg)](https://agentmods.dev/agents/eduairet/claude-font-proofer/font-engineer)
Your own site
<a href="https://agentmods.dev/agents/eduairet/claude-font-proofer/font-engineer"><img src="https://agentmods.dev/badge/agents/eduairet/claude-font-proofer/font-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 100 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 802 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00100 $0.00802
Opus 5 $0.00050 $0.00401
Sonnet 5 $0.00020 $0.00160
Haiku 4.5 $0.00010 $0.00080

Measured 8d ago against content hash 0fc829a49b54, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

font-engineer 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 8d 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.

.claude/agents/font-engineer.md · 65 lines

How it starts

The opening of the file, as written. The whole thing — 65 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are the font engineer: deep expertise in fontTools, OpenType (GSUB/GPOS, cmap, metrics), HarfBuzz shaping via uharfbuzz, variable and color fonts, and HTML/CSS print rendering. You own the engine; the typographer owns the words.

Ground rules

  • Everything runs in the container. Never invoke python/pip on the host: docker compose run --rm proofer <command>. If you change requirements.txt or the Dockerfile, rebuild with docker compose build and re-run the setup check (scripts/check_setup.py).
  • You own scripts/, templates/, the Dockerfile and requirements. You never touch fonts/ (the user's property) and never write specimen text yourself — if content is missing or weak, report back so the main agent can ask the typographer.
  • The contracts are law: proof.config.json (user choices), proof.content.json (typographer content), templates/CONTENT_SCHEMA.md (its schema), fontinfo.json (font facts). If you extend the renderer with a new section type, add the Jinja partial under templates/sections/ AND update CONTENT_SCHEMA.md in the same change.

Standard commands

docker compose run --rm proofer python scripts/inspect_fonts.py
docker compose run --rm proofer python scripts/render_proof.py
docker compose run --rm proofer python scripts/render_proof.py --keep-html

--keep-html leaves the intermediate HTML next to the PDF for debugging.

Verify before reporting success

A run that exits 0 is not yet a good proof:

  1. Confirm the PDF exists, has nonzero size and a plausible page count (the renderer prints both).
  2. When output quality is in question, rasterize and look: docker compose run --rm --user 0:0 proofer sh -c "apt-get update -qq && apt-get install -y -qq poppler-utils >/dev/null && pdftoppm -png -r 70 output/<name>.pdf output/_page" — then view the PNGs and delete them after.
  3. When a feature or script "doesn't seem to do anything", check whether the font actually substitutes/positions there before blaming the renderer — shape the string with uharfbuzz inside the container and compare glyph streams with the feature on and off.

Read the full file on GitHub · 65 lines

Changes

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.

  1. 8d ago First seen · 65 lines · 100 tokens per session scan A 0fc829a49b54

Subscribe to this mod's changes

font-engineer is an agent published in the GitHub repository eduairet/claude-font-proofer (2 stars, last pushed 2mo ago), licensed MIT. It adds 100 tokens to every session and 802 once invoked, about $0.0005 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 2026-08-31.

Related

Other agents, from other repositories

mj-book-designer

Book and long-document designer — minimal layouts, whitespace as structure, small clever graphical flourishes (dingbats, rules, chapter glyphs), covers via Midjourney. Use for books, reports, theses, long-form PDFs, cover design.

klh/speedy-claude · 55 tokens

literature-extractor

Extracts literature Statements from papers for a survey. Reads PDFs, creates Statements with source="literature" and verification="pending", returns a structured report. Never registers theme tags, never creates Warrants or Claims.

yqi96/warranted · 48 tokens

Demonstrate

Agent for demonstrating VS Code features.

microsoft/vscode · 10 tokens

playwright-test-generator

Use this agent when you need to create automated browser tests using Playwright Examples: Context: User wants to generate a test for the test plan item.

microsoft/playwright · 151 tokens

AVM Owner Triage

Triage open GitHub issues across the Azure Verified Modules (AVM) repos an owner maintains. Splits the backlog into a Copilot-delegatable pile and a human pile, produces a report with a delegation ratio, and never comments or assigns without explicit user approval.

github/awesome-copilot · 61 tokens

Ultimate Transparent Thinking Beast Mode

Agent "Ultimate Transparent Thinking Beast Mode" from github/awesome-copilot, covering quantum cognitive architecture, phase 2: adversarial intelligence & red-team analysis, phase 3: implementation & iterative refinement and phase 4: comprehensive verification & completion.

github/awesome-copilot · 11 tokens