Text Watermark Fountain (Robust Sync-Frame Version)

This skill enables the Agent to embed a string watermark into a text such that it can be recovered even if the text is partially modified, segments are deleted, or new sentences are inserted. It uses a custom Luby Transform (LT) Fountain Code combined with Sync Frames to map the watermark into a sequence of target lengths.

How it works (Robustness Mechanism)

1. Sync Markers: The encoding script periodically inserts a unique length pattern [19, 4, 19] (Sync Marker) followed by a Frame ID.
2. Self-Synchronization: The decoder searches the entire text for these markers using a sliding window. Even if middle segments are removed, the decoder can resynchronize using the next Sync Marker and know exactly which symbols it is looking at.
3. Redundancy: By repeating these frames throughout a long text, the watermark becomes extremely difficult to destroy.

Workflow: Embedding a Watermark

When a user asks to embed a watermark (e.g., "name_1") into a text: