Build an Enhanced Theme Locally

Inputs stay in this browser task

Choose one PNG, JPEG, or WebP image that you have the right to use. Builder reads the selected image and supported form fields in the current tab. Under the True MVP contract, it does not upload the selected image or theme JSON. The page must show the selected filename only inside the local workspace and must not send a local path, file content, or full hash as telemetry.

Build supported fields

Enter the portable appearance fields first, then review any platform-separated fields independently. Required fields must be labeled before export. Unknown or unsupported fields are not silently invented. Keep the preview, field form, and validation panel connected so the user can see which input produced each message.

• Select one supported image and confirm that it decodes in the browser.
• Set the supported appearance, safe-area, and task-mode fields documented by the frozen schema.
• Review macOS and Windows fields separately; do not copy one platform result into the other.
• Run structural checks before creating the local export.

Preview is an approximation

The browser preview helps check cropping, focus, contrast, and basic composition. It does not run Codex, the local Engine, or an exact Codex renderer. A good-looking preview cannot establish runtime behavior. If preview metadata cannot be decoded, show CANNOT_VERIFY for that check and keep the limitation next to the preview.

Validate before export

Builder must surface PASS, WARN, FAIL, or CANNOT_VERIFY from structural checks. PASS means the known checks completed without a blocking structural result. WARN requires review. FAIL blocks a ready-to-use claim and should identify the field or file that needs correction. CANNOT_VERIFY means a required parser, browser capability, metadata value, hash operation, or counterpart file was unavailable.

Export and evidence boundary

Export creates files for the user to save locally. The product does not promise persistence across refresh, cloud backup, account history, or automatic installation. The export should include available SHA-256 integrity values and the structural report, while explaining that hashes are not signatures or runtime evidence. Runtime remains NOT_VERIFIED unless a separate exact-build evidence record exists.

Next steps after export

Keep the theme JSON and its referenced image together in one named directory. Validate the saved pair again if files changed. Then read the Install guide and the correct platform page before using the independent local Engine. Save work first, review Apply and Restore, and do not continue with a FAIL result or unexpected script, executable, nested archive, traversal path, or extra file.

Local reset and errors

Reset must revoke temporary object URLs and clear Builder state from the current tab. Replacing an image must revoke the previous preview URL. If decoding, hashing, validation, or export fails, preserve an understandable error without claiming that a file was saved or tested. The user should be able to correct the input or reset without sending the file elsewhere.

Product boundary

Enhanced themes require the independent Codex Dream Skin local engine. Builder creates supported Enhanced theme files; it does not control a Codex installation or establish runtime compatibility. CodexSkin Tools is an independent project and is not affiliated with, endorsed by, or sponsored by OpenAI.