Okay, here are a few options for the post tag description “上市日期” (Shàngshì Rìqí) in Traditional Chinese, catering to different levels of formality and context:

**Option 1: Concise and Clear**

* **Description:** 標示產品首次於市場上推出之日期。 (Biāoshì chǎnpǐn shǒucì yú shìchǎng shàng tuīchū zhī rìqí.) – **Translation:** Indicates the date a product was first launched on the market.
* **Suitable for:** Most general use cases, blog posts, product announcements etc.

**Option 2: More Detailed and Informative**

* **Description:** 產品正式公開販售或提供的日期，通常指已完成所有必要程序，並可在市場上購買或使用的日期。 (Chǎnpǐn zhèngshì gōngkāi fànshòu huò tígōng de rìqí, tōngcháng zhǐ yǐ wánchéng suǒyǒu bìyào chéngxù, bìng kě zài shìchǎng shàng gòumǎi huò shǐyòng de rìqí.) – **Translation:** The date a product is officially released for sale or made available, usually indicating that all necessary procedures have been completed, and it is available for purchase or use in the market.
* **Suitable for:** Technical documentation, specific product-related posts.

**Option 3: Short & Sweet**

* **Description:** 產品上市時間。 (Chǎnpǐn shàngshì shíjiān.) – **Translation:** Product launch time.
* **Suitable for:** Simple tagging with a focus on quick information.

**Option 4: Emphasizing Region or Specifics**

* **Description:** 產品於 [國家/地區] 上市之日期，或特定產品系列的首次推出日期。 (Chǎnpǐn yú [Guójiā/Dìqū] shàngshì zhī rìqí, huò tèsì dìng chǎnpǐn xìliè de shǒucì tuīchū rìqí.) – **Translation:** The date a product was launched in [Country/Region], or the launch date of a specific product series.
* **Suitable for:** When you need to specify market launches, or multiple releases.

**Recommendation**

I recommend **Option 1** or **Option 3** for general WordPress tagging. They are concise, easy to understand, and serve their purpose well. You can adapt Option 4 if you need region-specific information.

**How to Add the Description in WordPress:**

1. **Navigate to Tags:** Go to your WordPress admin dashboard -> “Posts” -> “Tags”.
2. **Edit the Tag:** Find the tag “上市日期” and click “Edit.”
3. **Add Description:** In the editing screen, you’ll find a box labeled “Description.” Paste your chosen description from above into this box.
4. **Update/Save:** Click the “Update” button.

Good luck!