textfox is a Firefox theme designed for people who prefer a terminal-inspired visual style.
Borrowing it
Nothing to install: this file belongs to adriankarlen/textfox. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/adriankarlen/textfox/main/.agents/skills/firefox-chrome/SKILL.mdgit clone --depth 1 https://github.com/adriankarlen/textfoxWrote 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/adriankarlen/textfox/firefox-chrome)<a href="https://agentmods.dev/skills/adriankarlen/textfox/firefox-chrome"><img src="https://agentmods.dev/badge/skills/adriankarlen/textfox/firefox-chrome/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/adriankarlen/textfox/firefox-chrome"><img src="https://agentmods.dev/badge/skills/adriankarlen/textfox/firefox-chrome.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Rogue Agent · line 23 Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 | $0.00130 | $0.01736 |
| Opus 5.5 | $0.00052 | $0.00694 |
| Sonnet 5.5 | $0.00026 | $0.00347 |
| Haiku 4.5 | $0.00013 | $0.00174 |
Grade A, and why
firefox-chrome scanned grade A with 1 finding 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.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
Use **WebFetch** (raw github fetch is blocked for curl in this sandbox, WebFetch How it starts
The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.
firefox-chrome
textfox is a Firefox userChrome.css theme. It styles Firefox's internal browser
UI (toolbars, urlbar, tabs, menus). That UI is real DOM defined in Firefox's
source, with its own default CSS. Selectors, element IDs, and attributes change
between Firefox versions — this is the #1 cause of theme breakage, and an agent
cannot know the current internals from memory.
This skill bridges that gap: query Firefox's actual source for the latest release so every selector you write is verified, not guessed.
The truth source
firefox-release tree on searchfox = the latest shipped Firefox. textfox only
supports the latest version, so this is the only tree that matters.
Two operations:
1. Search (find selectors / elements / where something is styled)
Use the helper — it's sandbox-safe (no pipes, handles encoding, parses JSON):
sh tools/firefox-chrome/sf-search.sh "QUERY" "PATH_GLOB"
QUERY— a class, id, attribute, or any substring. Supports searchfox syntax.PATH_GLOB(optional) — e.g.*.css,*.xhtml. Narrow noisy queries with it.
Output: path:line: matched line, grouped by match kind. Zero matches for a
selector textfox already uses = strong signal Firefox renamed/removed it → search
the surrounding area for the new name.
Examples:
sh tools/firefox-chrome/sf-search.sh "urlbar-background" "*.css" # who styles it
sh tools/firefox-chrome/sf-search.sh "nav-bar" "*.xhtml" # find the DOM node
sh tools/firefox-chrome/sf-search.sh "tab-background-start" # everywhere
2. Read a full file (see structure / default rules in context)
Use WebFetch (raw github fetch is blocked for curl in this sandbox, WebFetch
works) against the github mirror, release branch:
https://raw.githubusercontent.com/mozilla-firefox/firefox/release/<PATH>
<PATH> is the path from a search hit (e.g. browser/themes/shared/urlbar-searchbar.css).
Or read it rendered (with line numbers) on searchfox via WebFetch:
https://searchfox.org/firefox-release/source/<PATH>
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 · 150 lines · 130 tokens per session scan A 0fd1566550c3
firefox-chrome is a skill published in the GitHub repository adriankarlen/textfox (1,707 stars, last pushed 14d ago), licensed MPL-2.0. It adds 130 tokens to every session and 1,736 once invoked, about $0.0005 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
firefox-chrome compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| firefox-chromeadriankarlen/textfox | Skill | 1.7k | 14d ago | MPL-2.0 | A | 130 | Claude Code, Codex |
| popular-web-designsNousResearch/hermes-agent | Skill | 261k | yesterday | MIT | A | 23 | Claude Code, Codex |
| designlang-tokensManavarya09/design-extract | Skill | 4.8k | yesterday | MIT | A | 30 | Claude Code |
| video-shot-demosUnclecheng-li/AI_Animation | Skill | 1.7k | 11d ago | MIT | A | 166 | Claude Code, Codex |
| hero-slider-settleUnclecheng-li/AI_Animation | Skill | 1.7k | 11d ago | MIT | A | 0 | Claude Code, Codex |
| animateericrisco/rsc-harness | Skill | 503 | 2d ago | MIT | A | 75 | Claude Code, Codex |
| reimagine-itKayforkind/reimagine-it | Skill | 212 | 5d ago | MIT | A | 230 | Claude Code |