Install a Codex theme from CodexThemes

Download a published theme's portable package from codexthemes.ai and unpack its source files into ~/.codexthemes/themes/<theme-id>/. This skill is standalone: its TypeScript scripts own the download, validation, and local installation. It does not search the gallery (codex-theme-finder), create themes (codex-theme-creator), or submit them (codex-theme-submitter). Applying belongs to codex-theme-switcher — but a successful install chains directly into it (Step 4); installing files and stopping is not a finished job. The only required local tools are Node.js 20+ and npx.

Read references/download-api.md before diagnosing an unexpected API response or changing endpoint behavior. Run all commands from the installed skill directory.

Step 1: identify the theme

Resolve what to install to a theme id — the lowercase slug from codex-theme-finder results or from a https://codexthemes.ai/themes/<theme-id> URL. The script accepts either form. If the user only describes a style without naming a theme, find candidates with codex-theme-finder first instead of guessing ids.

Step 2: install

npx tsx scripts/install-theme.ts <theme-id | codexthemes.ai theme URL> [--force]

Downloads work without any API key inside a free anonymous quota, so do not demand a key up front. When a key is already configured (CODEXTHEMESAPIKEY environment variable or ~/.codexthemes/credentials.json), the script sends it automatically for higher limits.

The script validates the downloaded package (format, schema version, matching theme id, safe relative filenames, ≤30 MB) before writing anything, then unpacks theme.json, the stylesheet, the artwork, and the readme into ~/.codexthemes/themes/<theme-id>/. It refuses to overwrite an existing non-empty theme directory; pass --force only after the user confirms replacing their local copy — the directory may hold their own edits.

Updating an installed theme: published themes are updated in place on codexthemes.ai, so when the user asks to update, upgrade, or re-download a theme they already installed, re-run the install with --force — the update request itself is the confirmation, unless the local copy holds edits the user made (then warn first). After the files land, continue into Step 4 so the running app actually switches to the new version; a hot swap of the same theme id re-injects the updated CSS.

Step 3: handle quota and rate limits

On HTTP 429 or 402 the free quota is exhausted; the script's error message includes any Retry-After value. Do not retry in a loop. Tell the user the free download quota is used up and guide them to configure a personal API key:

1. Create a key at https://codexthemes.ai/settings/apikeys.
2. Store it: printf '%s' "<api-key>" | npx tsx scripts/apikey.ts set (stdin keeps the key out of shell history; apikey.ts set <key> also works).
3. Re-run the install.

Check the current key state with npx tsx scripts/apikey.ts status; remove a stored key with npx tsx scripts/apikey.ts clear. Never print a full key (scripts only show a masked form), never write it into a project file, and never commit it.

On 401/403 the configured key is invalid or revoked — guide the user to create a fresh key the same way. On 404 the theme id does not exist; re-check the id with codex-theme-finder.

Step 4: activate, or hand the user the exact next reply

An install request means the user wants to see the theme in Codex, not merely store its files. Report the installed path (~/.codexthemes/themes/<theme-id>/), the theme version, and the files written — then continue directly into activation with codex-theme-switcher. If codex-theme-switcher is not installed, bootstrap it the same way this skill was bootstrapped (npx skills add codexthemes/skills --skill codex-theme-switcher -g -a codex).

• If Codex already exposes its debugging endpoint, hot-swap now with the switcher's switch-theme.ts apply <theme-id> and verify with switch-theme.ts status — a hot swap is reversible and needs no confirmation beyond the install request itself.
• If activation requires restarting Codex, do not restart silently and do not stop at "installed". End by telling the user the exact reply that continues, for example: "Reply apply and I will restart Codex to activate <theme-id>." When they reply, follow the switcher's --launch flow.

Never end the conversation with only "files installed, not applied" and no actionable next step, and never claim the theme is active until the switcher's status reports active.