discourse-ai/lib/ai_moderation/spam_report.rb
Sam 47f5da7e42
FEATURE: Add AI-powered spam detection for new user posts (#1004)
This introduces a comprehensive spam detection system that uses LLM models
to automatically identify and flag potential spam posts. The system is
designed to be both powerful and configurable while preventing false positives.

Key Features:
* Automatically scans first 3 posts from new users (TL0/TL1)
* Creates dedicated AI flagging user to distinguish from system flags
* Tracks false positives/negatives for quality monitoring
* Supports custom instructions to fine-tune detection
* Includes test interface for trying detection on any post

Technical Implementation:
* New database tables:
  - ai_spam_logs: Stores scan history and results
  - ai_moderation_settings: Stores LLM config and custom instructions
* Rate limiting and safeguards:
  - Minimum 10-minute delay between rescans
  - Only scans significant edits (>10 char difference)
  - Maximum 3 scans per post
  - 24-hour maximum age for scannable posts
* Admin UI features:
  - Real-time testing capabilities
  - 7-day statistics dashboard
  - Configurable LLM model selection
  - Custom instruction support

Security and Performance:
* Respects trust levels - only scans TL0/TL1 users
* Skips private messages entirely
* Stops scanning users after 3 successful public posts
* Includes comprehensive test coverage
* Maintains audit log of all scan attempts


---------

Co-authored-by: Keegan George <kgeorge13@gmail.com>
Co-authored-by: Martin Brennan <martin@discourse.org>
2024-12-12 09:17:25 +11:00

48 lines
1.6 KiB
Ruby

# frozen_string_literal: true
module DiscourseAi
module AiModeration
class SpamReport
def self.generate(min_date: 1.week.ago)
spam_status = [Reviewable.statuses[:approved], Reviewable.statuses[:deleted]]
ham_status = [Reviewable.statuses[:rejected], Reviewable.statuses[:ignored]]
sql = <<~SQL
WITH spam_stats AS (
SELECT
asl.reviewable_id,
asl.post_id,
asl.is_spam,
r.status as reviewable_status,
r.target_type,
r.potential_spam
FROM ai_spam_logs asl
LEFT JOIN reviewables r ON r.id = asl.reviewable_id
WHERE asl.created_at > :min_date
),
post_reviewables AS (
SELECT
target_id post_id,
COUNT(DISTINCT target_id) as false_negative_count
FROM reviewables
WHERE target_type = 'Post'
AND status IN (:spam)
AND potential_spam
AND target_id IN (SELECT post_id FROM spam_stats)
GROUP BY target_id
)
SELECT
COUNT(*) AS scanned_count,
SUM(CASE WHEN is_spam THEN 1 ELSE 0 END) AS spam_detected,
COUNT(CASE WHEN reviewable_status IN (:ham) THEN 1 END) AS false_positives,
COALESCE(SUM(pr.false_negative_count), 0) AS false_negatives
FROM spam_stats
LEFT JOIN post_reviewables pr USING (post_id)
SQL
DB.query(sql, spam: spam_status, ham: ham_status, min_date: min_date).first
end
end
end
end