Here are a few options for a WordPress post_tag description for “30天” (三十天) in Traditional Chinese, depending on the tone and context you want to convey:

**Option 1: Simple and Direct (Good for general use)**

* **Description:** 三十天。
* **Translation:** Thirty Days.
* **Use Case:** This is the most basic and accurate description, suitable for simply labeling content related to a 30-day period.

**Option 2: Slightly More Informative (If the tag represents a challenge, plan, or journey)**

* **Description:** 為期三十天。
* **Translation:** Lasting thirty days.
* **Use Case:** This subtly implies a commitment or duration. Useful if your posts cover challenges, personal projects or any course or set of instructions aimed for a 30-days long process.

**Option 3: Emphasizing a Milestone or Period (Good for tracking a habit or progress)**

* **Description:** 三十天，里程碑。
* **Translation:** Thirty days, a milestone.
* **Use Case:** Useful if you see this tag representing some sort of evaluation. It suggests the tracking of an activity, project or habit.

**Option 4: Detailed and Specific (If context is important)**

* **Description:** 包含所有與三十天相關內容。
* **Translation:** Includes all content related to thirty days.
* **Use Case:** This description is perfect if you want to clarify that the tag is a general indicator for all 30-day-long projects.

**How to use the description in WordPress:**

1. **Go to the “Tags” section:** In your WordPress dashboard, navigate to “Posts” > “Tags”.
2. **Find the Tag:** Locate the “30天” (三十天) tag in your tag list, or create it if you haven’t already.
3. **Edit the Tag:** Click “Edit” on this tag.
4. **Enter the Description:** In the “Description” field, paste one of the descriptions above, or customize it to your needs.
5. **Update the Tag:** Click “Update” to save the changes.

Remember to choose the description that best fits the content associated with the “30天” (三十天) tag on your website!