I’m trying to setup the AI spam detector for my own Discourse instance, but have several questions: The system prompt of spam detector persona can’t be edited. I can create a new persona but there is no field to make Discourse know that it is going to be used as a spam detector? I want to use Qwen…

I just did a quick setup and it works fine selecting the custom persona for spam. [Screenshot 2025-11-19 at 1.54.11 PM] [Screenshot 2025-11-19 at 1.51.51 PM] Let us know again if you are not able to do so via /discourse-ai/ai-spam

Hi there, to answer your question: [image] lilydjwg: What does the tokenizer do here? From the docs: [image] Discourse AI - Large Language Model (LLM) settings page What is tokenizer? The tokenizer translates strings into tokens, which is what a model uses to understand the input.

Thanks, but I know what a tokenizer is. What I don’t know is what Discourse uses it for, and what would happen if I picked the wrong tokenizer? I don’t need a tokenizer to call an LLM anyway.

[image] lilydjwg: The system prompt of spam detector persona can’t be edited. Can you try visiting this https://<your-site>/admin/plugins/discourse-ai/ai-spam - it should allow you to select your persona insert custom instructions and test against a post [image] lilydjwg: Does QwenToke…

[image] nat: insert custom instructions IIUC this instruction is concatenated to the system prompt instead of replacing it, making the prompt even longer and have mixed languages… [image] nat: Yup you can go ahead and do that, then run the “Test” But passing the test doesn’t mean ther…

Thanks, so that “spam detector” label only affects the list filering of personas? I’ll setup a test environment and try it.

I checked the source code. If I didn’t make mistakes, the tokenizer is used for two things: count tokens for statistics and price estimation, and truncate posts to the set limit. So it shouldn’t affect me a lot if a wrong one is used.

Frustrations on AI spam detector

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NateDhaliwal (Nate Dhaliwal) November 19, 2025, 3:59am 2

Hi there, to answer your question:

From the docs:

Topic		Replies	Views
Discourse AI - Large Language Model (LLM) settings page Site Management how-to , ai	21	3512	May 9, 2026
AI powered Spam detection Announcements ai , spam	11	1108	January 11, 2025
Discourse AI - Spam detection Site Management moderation , how-to , ai , spam	32	4090	March 10, 2026
Introducing Discourse AI Blog	26	3988	May 4, 2023
What's the cheapest/best AI to use for AI Spam? Support ai , spam	6	335	March 18, 2025

Frustrations on AI spam detector

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