Old tool results can be cleared after a long idle gap (tengu_zany_pike), and file re-reads return full content when that may happen

What

A tool call is one action Claude takes, such as reading a file or running a command, and its result stays in the conversation. This release adds a way to clear older tool results after the conversation has sat idle for a long time, plus changes so Claude is not pointed at results that are gone.

• On the first request after at least 3900 seconds of idleness, and when the conversation holds at least 20 tool uses that can be cleared, Claude Code can attach a server-side context edit of type clear_tool_uses_20250919. It keeps the last 5 tool uses.
• The mode comes from the tengu_zany_pike gate, which accepts on, shadow or off. shadow only records what would happen and sends no edit. If the value comes from the built-in fallback, the mode is treated as unknown: no new clearing is planned, and planning only continues where earlier messages show the server already cleared tool results.
• The planning happens in the main code that builds each request.
• The dedupUnchangedReads setting now turns off when the caller disabled it or when an idle clearing edit would apply to the current messages. A re-read then returns the whole file instead of a short "unchanged" note pointing at a copy about to be cleared. Otherwise it keeps its default.
• @-mentioned files follow the same rule: when earlier tool results may have been cleared after idle time, Claude Code no longer answers with an already_read_file note and calls Read with dedupUnchangedReads disabled, so the real content comes back. Memory prefetch passes the same signal along as earlierReadsMayBeCleared.

Why

If it runs, coming back to a session after about an hour could mean older tool outputs are no longer in Claude's context, which changes what Claude can see from earlier in the session. The re-read changes stop Claude from being told it already has a file's content when that copy has been cleared.