# firefox-css-theme

Scaffolds, live-debugs, and installs Firefox CSS themes.

- **Type:** MCP server
- **Trust:** 85/100 (A), scored on the package rubric
- **Verification:** verified (build provenance)
- **Version:** 0.2.8
- **Author:** Eason Wong
- **License:** MIT
- **npm:** firefox-css-theme
- **Source:** https://github.com/easonwong-de/Firefox-CSS-Theme
- **Compatible clients:** claude-code, cursor, copilot, gemini (basis: transport)

## Trust

85/100 (A), scored on the package rubric
- Publisher verified: no
- Build provenance: verified attestation
- npm trusted publishing (OIDC): yes
- Install scripts: nothing suspicious found
- Prompt-injection scan: not run
- Obfuscation scan: not run
- Evidence age: 0 days

## Security scan

- **Status:** clean
- **Scanned:** 2026-09-06T00:54:05.388Z
- **Version scanned:** 0.2.8
- **CVEs:** none found by OSV at scan time

## Tools

11 declared. Statically extracted from the shipped source — a floor on the surface, not a census.
- `launch_browser` — Launch a Firefox instance with chrome debugging capabilities enabled.
- `close_browser` — Close the running Firefox instance.
- `customize_toolbar` — Activate or manage the Firefox Customise Toolbar mode in the browser chrome.
- `get_ui_tree` — Retrieve the hierarchical DOM tree of the Firefox chrome user interface window.
- `query_ui_elements` — Find elements in the Firefox UI chrome document matching a CSS selector.
- `get_computed_styles` — Extract computed CSS properties for a Firefox UI chrome element.
- `inject_theme_css` — Inject or replace a live stylesheet in the Firefox window.
- `remove_theme_css` — Remove an injected stylesheet from the Firefox window.
- `list_theme_css` — List all custom stylesheets currently injected in the Firefox window.
- `take_ui_screenshot` — Capture a PNG screenshot of the Firefox browser chrome window or a specific UI component.
- `execute_chrome_javascript` — Execute privileged JavaScript code in the Firefox chrome window context.

## Install

**Verdict: install** — No blocking findings and no open coverage gaps — safe to install as configured.
**Config** (claude-code):
```json
"{\n  \"mcpServers\": {\n    \"firefox-css-theme\": {\n      \"command\": \"npx\",\n      \"args\": [\n        \"-y\",\n        \"firefox-css-theme\"\n      ]\n    }\n  }\n}"
```

## Blast radius

Extensive to critical — no credential declaration found, from the publisher, the upstream registry, or the README. Known so far: deletes data; runs on your machine.
- Floor 36, ceiling 60 (tier: unknown)
- `unknown` means the floor and ceiling land in different bands — not measured enough to name one. It does not mean low.
- This is impact, not likelihood. A high radius is not a defect: a filesystem server is supposed to write files. It is never part of the trust score.

## Machine-readable views of this entry

- Signed JSON: https://forgeregistry.com/api/v1/packages/firefox-css-theme
- Install plan: https://forgeregistry.com/api/v1/packages/firefox-css-theme/install-plan
- Alternatives: https://forgeregistry.com/api/v1/alternatives/firefox-css-theme
- HTML page: https://forgeregistry.com/registry/firefox-css-theme
- MCP: POST https://forgeregistry.com/api/mcp → `forge_get_package` / `forge_install_plan`

## About this document

Generated by Forge (https://forgeregistry.com) — a compact rendering of the same record served, signed, at the JSON URL above. Trust and scan facts are the registry's own measurements; anything Forge did not measure is named as unmeasured rather than omitted.