The same per-session condition routes error text to logs instead of the screen.
What
When the remote context fetch fails and the same unnamed per-session condition holds, you see only "Couldn't fetch context from remote" and the underlying error goes to the log at error level; otherwise the error text is still shown inline.
Evidence
Couldn't fetch context from remote
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
Names in the bundle/context
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Added since
A small documentation edit on whats-new-fable-5-1 touched a line naming /context after this was published.
To keep thinking valid across a long session, treat the conversation as append-only. Add instructions with a [mid-conversation system message](https://platform.claude.com/docs/en/build-with-claude/mid-conversation-system-messages) ([turn-s…models/fable-5-1/whats-new-fable-5-1 see the edit
Confirmed since
Anthropic's documentation has since written up /context, on How Claude Code uses prompt caching.
[Compaction](/docs/en/context-window#what-survives-compaction) replaces your message history with a summary. By design, this invalidates the conversation layer, since the next request has a new, shorter history that doesn't share a prefix …prompt-caching see the edit
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agrees
Anthropic's documentation has since written up /context, on How Claude Code uses prompt caching.