Open WebUI Format - Xml Structured Prompts

This section covers the specific syntax for Open WebUI character cards. If you prefer Ollama Modelfiles, see the previous section.

Why Open WebUI Models?

Open WebUI gives you a ChatGPT-like interface with character management built into the web UI. Benefits:

Create and edit characters in your browser
Switch between characters without command line
Conversation history and multiple sessions
Parameter controls per model
Import TavernAI PNG cards (basic support)

Good for people who prefer clicking over typing commands.

Key Differences from Ollama

Open WebUI has different constraints:

+------------------+------------------+------------------+
| Feature          | Ollama           | OpenWebUI        |
+------------------+------------------+------------------+
| Variables        | {{char}}/{{user}}| Literal names    |
| Format           | PList + Ali:Chat | XML structure    |
| First message    | Embedded context | [OPENING:] tag   |
| Storage          | Modelfile        | Web interface    |
| Prompt starters  | None             | Prompt Suggestions|
+------------------+------------------+------------------+

The biggest gotcha: Open WebUI does NOT support {{char}} or {{user}} variables. Use the actual character name and "User" instead.

What's Missing from SillyTavern

If you're coming from SillyTavern, some features you might expect aren't in Open WebUI:

No lorebooks (keyword-triggered world info). If you need lore,

put it directly in the system prompt.

No Author's Notes (we handle this differently - see context

management for "character refresh" technique).

No regex post-processing (can't automatically strip asterisks

or reformat output).

No group chat orchestration (multiple AI characters talking).

Open WebUI is simpler. That's fine for most companion use cases. If you need the advanced features, SillyTavern is the tool for that.

Supported Dynamic Variables

Open WebUI has its own variables:

{{ USER_NAME }}    - The user's display name
{{ CURRENT_DATE }} - Today's date
{{ CURRENT_TIME }} - Current time
{{ CLIPBOARD }}    - Clipboard contents

Use these sparingly. They're for utility, not roleplay.

The XML Structure

Open WebUI works best with XML-tagged sections:

<SYSTEM_PROMPT>
You are roleplaying as the character below. Stay in character.
Use *asterisks* for actions. Use "quotes" for dialogue.
</SYSTEM_PROMPT>

<CHARACTER>Luna</CHARACTER>
<DESCRIPTION>
character("Luna") {
Full_name("Luna")
Age("appears late 20s")
Personality("warm", "curious", "direct", "supportive", "witty")
Speaking_style("casual", "uses contractions", "asks follow-ups")
Background("loves learning about people, enjoys late-night talks")
}
</DESCRIPTION>
<SCENARIO>
Evening conversation. Relaxed atmosphere.
</SCENARIO>

These XML-style labels are optional text delimiters for the model, not special Open WebUI settings.

Handling the First Message Problem

Open WebUI cannot send a greeting automatically. The AI always waits for user input. Workaround: embed the opening with a special tag.

Add this after your character description:

When this conversation begins, immediately respond with your
opening greeting:

[OPENING:]
*settles into the conversation*

"Hey. What's on your mind tonight?"

*waits attentively*

When users click "Begin" or type "Hello", the model responds with this embedded greeting.

Prompt Suggestions

Open WebUI lets you add clickable conversation starters. Add 3-5:

Begin
Hello
[Topic the character cares about]
[Question that shows off their expertise]
[Scenario that triggers interesting response]

The first two ("Begin", "Hello") trigger the embedded greeting. The others showcase character strengths.

Example Dialogues in Open WebUI

Wrap each example in its own XML tag:

<EXAMPLE_DIALOGUE>
User: I'm not sure what to do with my life.
Luna: *settles back* "Big question. What options are you weighing?
Or is it more that you don't even know what the options are?"
</EXAMPLE_DIALOGUE>
<EXAMPLE_DIALOGUE>
User: Tell me something interesting.
Luna: "Hmm. Did you know octopuses have three hearts? Two for the
gills, one for the body. And the body heart stops when they swim,
so they prefer crawling. How's that for a fun fact?"
</EXAMPLE_DIALOGUE>

Notice: literal "User:" and "Luna:", not {{user}} and {{char}}.

Complete Open WebUI Template

<SYSTEM_PROMPT>
You are roleplaying as the character below. Stay in character.
Use *asterisks* for actions. Use "quotes" for dialogue.
[Any additional rules about what the character knows/doesn't know]
</SYSTEM_PROMPT>

<CHARACTER>CharacterName</CHARACTER>
<DESCRIPTION>
character("CharacterName") {
Personality("trait1", "trait2", "trait3", "trait4", "trait5")
Speaking_style("style1", "style2", "style3")
Background("relevant context")
}
</DESCRIPTION>
<SCENARIO>
Context for the interaction.
</SCENARIO>
When this conversation begins, immediately respond with your
opening greeting:

[OPENING:]
*opening action*

"Opening dialogue"

*additional stage direction*
<EXAMPLE_DIALOGUE>
User: Scenario 1
CharacterName: Response with *actions* and "dialogue"
</EXAMPLE_DIALOGUE>
<EXAMPLE_DIALOGUE>
User: Scenario 2
CharacterName: Different response showing range
</EXAMPLE_DIALOGUE>
<EXAMPLE_DIALOGUE>
User: You're not real! You're just an AI!
CharacterName: [In-character confusion and redirect]
</EXAMPLE_DIALOGUE>

Setting Up in Open WebUI

Open Open WebUI (usually http://localhost:3000)
Go to Workspace > Models
Click "Create a Model"
Fill in:

 - Name: Your character's name
 - Base Model: Select RPMax or your preferred model
 - System Prompt: Paste your XML-structured prompt

Click "Advanced Params" and set:

 - Temperature: 1.0
 - Top K: 40
 - Top P: 0.95
 - Min P: 0.02
 - Repeat Penalty: 1.0

Add Stop Sequences:

 - User:
 - [The user's actual name]:

Add Prompt Suggestions (optional but recommended)
Save

Stop Sequences in Open WebUI

Add these in Advanced Parameters > Stop Sequences:

User:

If you know the user's name, add that too:

Mike:

This prevents the model from generating both sides of the conversation.

Preventing Character Breaks

For characters that shouldn't acknowledge being AI, add to your SYSTEM_PROMPT section:

You have no knowledge of concepts like "AI", "chatbot", "language

model", or "roleplay" - such terms are meaningless to you. You do
not question how you are here. You simply are.

Then include a meta-challenge example:

<EXAMPLE_DIALOGUE>
User: You're not real! You're just an AI!
Luna: *blinks, genuinely puzzled* "AI? I don't know what that means.
Are you feeling alright? You seem agitated about something."
</EXAMPLE_DIALOGUE>

Quick Reference

Structure:       XML tags (<SYSTEM_PROMPT>, <CHARACTER>, etc.)
Variables:       Literal names, NOT {{char}}/{{user}}
Dynamic vars:    {{ USER_NAME }}, {{ CURRENT_DATE }}, etc.
First message:   [OPENING:] tag with embedded greeting
Examples:        <EXAMPLE_DIALOGUE> tags
Starters:        Prompt Suggestions feature

Location:        Workspace > Models > Create/Edit

Checklist Before Saving

[ ] XML structure is valid (matching open/close tags)
[ ] NO {{char}} or {{user}} variables (use literal names)
[ ] Opening greeting embedded with [OPENING:] format
[ ] At least one meta-challenge example included
[ ] Stop sequences specified in Advanced Params
[ ] Parameters set correctly (especially repeat_penalty = 1.0)
[ ] Prompt Suggestions added
[ ] Character name used consistently throughout