codex-theme-creator

A workflow for creating and checking visual themes for the Codex desktop app. It can adapt a theme to a visual brief or reference image while keeping the app’s normal layout and behavior within the chosen limits.

In plain words
What is it for?
Use it to create, redesign, validate, preview, package, apply, and restore Codex desktop themes.
Why use it?
It provides a defined way to change the app’s appearance without directly modifying protected application files or user data.

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

Made for: Claude Code, Codex.

Per session 86 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,863 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 $0.00086 $0.03863
Opus 5 $0.00043 $0.01931
Sonnet 5 $0.00017 $0.00773
Haiku 4.5 $0.00009 $0.00386

Measured 2d ago against content hash 1c76ed35931f, 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-creator 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 9 executable files (scripts/apply-theme.ts, scripts/export-theme.ts, scripts/paths.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-creator/SKILL.md · 232 lines

How it starts

The opening of the file, as written. The whole thing — 232 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create a Codex theme

Create a reversible decorative theme without modifying app.asar, the signed app bundle, WindowsApps, user tasks, or authentication data. Preserve native layout and interaction behavior unless the chosen layout mode explicitly permits a bounded composition change.

Authority boundary

Use this skill as the sole design and QA authority for a new Codex theme. Do not read, copy, or combine another installed theme skill, finished theme manifest, finished theme CSS, or local theme collection unless the user explicitly names that source. Do not describe the workflow as combining this skill with “local theme conventions.” Start from this skill's matching skeleton and the user's brief or reference image.

This skill is standalone. Its TypeScript scripts own scaffolding, validation, reversible session application, and restore. Never detect, invoke, read configuration from, or claim a dependency on CodeDrobe, Dream/Fiona, or another theme injector unless the user explicitly asks to use that product. Do not reuse their marker names or runtime data. The only required local tools are Node.js, npx, and the official Codex desktop app.

Managed storage

Keep every generated theme file in the managed library ~/.codexthemes unless the user explicitly requests another location:

  • editable source and artwork: ~/.codexthemes/themes/<theme-id>/
  • previews: ~/.codexthemes/themes/<theme-id>/previews/
  • shareable packages: ~/.codexthemes/exports/
  • runtime state: ~/.codexthemes/state/

Never create a staging, scratch, or temporary copy of theme files in or near the current workspace (for example a .codexthemes-stage directory). If the sandbox or permission mode blocks writing to ~/.codexthemes, ask the user to approve writing there instead of writing somewhere else first and moving files later.

Read the required references

Before creating or substantially redesigning a theme, read these files completely:

  • references/design-playbook.md: layout modes, semantic palette, selectors, and surface coverage.
  • references/qa-checklist.md: real-app acceptance matrix and hard failures.
  • references/theme-schema.md: manifest and portable package contract.
  • references/asset-rights.md: user-material handling and submission handoff.

Read the full file on GitHub · 232 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. 2d ago First seen · 232 lines · 86 tokens per session scan A 1c76ed35931f

Subscribe to this mod's changes

codex-theme-creator is a skill published in the GitHub repository codexthemes/skills (6 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 86 tokens to every session and 3,863 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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