Uploaded August 2026 | Updated September 2026, 2 weeks ago
Link to transcript: magazine.sebastianraschka.com/p/claude-watermarking
Link to the slides: sebastianraschka.com/pdf/slides/2026-08-18-claude-watermarking.pdf
This video explains how Anthropic's text watermarking for Claude works. In particular, it explains how the next-token sampling process in LLMs work, and how this is modified to implement the watermarking technique. A thorough understanding of the watermarking is useful because it helps us understand the implementation shortcomings as well.
0:00 How Claude's Text Watermarking Works
5:38 How LLM Text Generation Works
11:39 How Next-Token Sampling Works
16:19 From Sampling to Watermarking
18:23 Random Seeds and Deterministic Sampling
20:03 How the Watermarking Key Works
24:45 Where the Watermark Is Applied
26:13 How Watermark Detection Works
28:00 How to Remove a Watermark
30:17 How the Watermark Scoring Function Works
31:18 SynthID Text and Tournament Sampling
34:33 Random Watermarking Functions
36:36 Tournament Sampling Step by Step
39:18 Detecting Watermarks Without Rerunning the LLM
43:26 Watermarking Summary and Limitations
44:34 What This Means for AI-Generated Text
47:13 Final Thoughts
Check out my website for more articles and resources on LLMs: sebastianraschka.com
Link to transcript: magazine.sebastianraschka.com/p/claude-watermarking
Link to the slides: sebastianraschka.com/pdf/slides/2026-08-18-claude-watermarking.pdf
This video explains how Anthropic's text watermarking for Claude works. In particular, it explains how the next-token sampling process in LLMs work, and how this is modified to implement the watermarking technique. A thorough understanding of the watermarking is useful because it helps us understand the implementation shortcomings as well.
0:00 How Claude's Text Watermarking Works
5:38 How LLM Text Generation Works
11:39 How Next-Token Sampling Works
16:19 From Sampling to Watermarking
18:23 Random Seeds and Deterministic Sampling
20:03 How the Watermarking Key Works
24:45 Where the Watermark Is Applied
26:13 How Watermark Detection Works
28:00 How to Remove a Watermark
30:17 How the Watermark Scoring Function Works
31:18 SynthID Text and Tournament Sampling
34:33 Random Watermarking Functions
36:36 Tournament Sampling Step by Step
39:18 Detecting Watermarks Without Rerunning the LLM
43:26 Watermarking Summary and Limitations
44:34 What This Means for AI-Generated Text
47:13 Final Thoughts
Check out my website for more articles and resources on LLMs: sebastianraschka.com
