Internal prompt-cache-break diagnostics were restructured, with a new bypass for one message source and for disk-seeded cache state
Claude Code's internal logic for detecting "prompt cache breaks" (when a cached prompt prefix stops being reusable) was reorganized: the threshold logic for deciding when a break occurred now lives in a shared helper. A new branch handles the case where a specific message source reports no session state, logging a diagnostic event with request ID and cache token counts instead of just returning early. There's also a new early exit that skips break diagnosis entirely when the cache state was seeded from disk.
This is internal diagnostic plumbing rather than a user-facing feature; it should make prompt-cache-break issues easier to trace by giving certain edge cases (missing session state, disk-seeded cache) their own explicit handling instead of falling through to generic logic.