codex-theme-switcher

A local command-line tool for changing the appearance of the Codex desktop app using installed themes. It can apply, switch, restore, and report the active theme.

In plain words
What is it for?
Use it to list installed themes, activate one, switch between themes, restore Codex's original appearance, and check the current theme.
Why use it?
It lets you manage the app's look without changing the signed application files, and lets you confirm which theme is currently active.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/codexthemes/skills/codex-theme-switcher
Any agent
npx skills add codexthemes/skills --skill codex-theme-switcher
Clone the repo
git clone --depth 1 https://github.com/codexthemes/skills

Made for: Claude Code, Codex.

Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,558 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00075 $0.01558
Opus 5 $0.00037 $0.00779
Sonnet 5 $0.00015 $0.00312
Haiku 4.5 $0.00007 $0.00156

Measured 2d ago against content hash 41dd651e98eb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

codex-theme-switcher 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 2d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (scripts/paths.ts, scripts/readability.ts, scripts/self-test.ts, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/codex-theme-switcher/SKILL.md · 83 lines

How it starts

The opening of the file, as written. The whole thing — 83 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Switch the active Codex theme

Apply a theme from the managed local library ~/.codexthemes/themes/<theme-id>/ to the running Codex desktop app, switch between installed themes, restore the native look, and verify what is actually active. This skill is standalone: its TypeScript scripts own the reversible injection runtime. It does not create or edit themes (codex-theme-creator), install them from the gallery (codex-theme-installer), or publish them (codex-theme-submitter). The only required local tools are Node.js 20+, npx, and the official Codex desktop app.

Run all commands from the installed skill directory. The runtime injects only an owned <style> element over Codex's loopback-only debugging endpoint; it never modifies the signed app bundle, and it themes every open Codex page, not just one window.

Step 1: pick the theme

npx tsx scripts/switch-theme.ts list

Lists every installed theme (id, name, layout mode) and which one is currently active. Themes arrive in the library from codex-theme-creator (created locally) or codex-theme-installer (downloaded from codexthemes.ai). If the theme the user wants is not listed, hand off to those skills instead of guessing paths.

Step 2: apply or switch

npx tsx scripts/switch-theme.ts apply <theme-id>
  • If Codex is already exposing its debugging endpoint (it is after any previous themed launch), this hot-swaps the theme in place on every open page — no restart, output {"status": "active", "pagesThemed": n}.
  • If there is no endpoint (first apply of this app session, or Codex was fully quit), ask the user for explicit permission to restart Codex, then rerun with --launch:
npx tsx scripts/switch-theme.ts apply <theme-id> --launch

--launch prints {"status": "scheduled"} and hands the quit → relaunch → inject sequence to a detached helper that survives the restart (an agent hosted inside Codex dies with it; expect the tool call to be interrupted). Never build your own restart mechanism — no shell wrappers, launchd or scheduled tasks, or script copies; the helper already survives the restart.

Read the full file on GitHub · 83 lines

Files

What ships with it

5 files 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.

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. 2d ago First seen · 83 lines · 75 tokens per session scan A 41dd651e98eb

Subscribe to this mod's changes

codex-theme-switcher is a skill published in the GitHub repository codexthemes/skills (6 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 75 tokens to every session and 1,558 once invoked, about $0.0004 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.

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