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Claude Code is steganographically marking requests

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first seen Jun 30, 2026 · last seen Jul 5, 2026 · published Jun 30, 2026

Featured on 1 day: July 1, 2026.

Posted on X

2026-07-01
Claude Code embeds invisible markers in every request — zero-width characters that survive copy-paste. Means Anthropic can fingerprint which prompts came from their IDE vs API, even if the text looks identical. Worth knowing if you're routing Claude calls.