DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.
Forking a session tells the model the fork is separate
You'll notice
Useful3Signal3
Sessions
After forking, Claude is told the fork is a separate session reachable by name.
What's wrong with this entry?
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What
After forking, Claude is now told that the fork runs as its own session, that its work is invisible to the current conversation, and that it can be reached by name through the session roster. This branch previously attached nothing.
Details
The message is produced only when cross-session messaging applies; otherwise nothing is attached.
Evidence
The fork runs as its own separate session
Strings lifted out of the shipped bundle, so the claim above can be checked against them.