Repository navigation
Cache-miss attribution from the diagnostics field in transcripts #1804
Description
Newer Claude Code transcripts carry message.diagnostics.cache_miss_reason on some
assistant records (types seen: previous_message_not_found, messages_changed,
tools_changed, system_changed, model_changed, unavailable). ccusage sums cache creation
and read tokens but does not surface why a cache was rebuilt. I wrote a small standalone
tool that does (https://github.com/CedricConday/cachemiss): per rebuild, the reason, the
tokens rewritten and the write premium, attributed to sub-agents via the subagents/
transcript files. If you would take a "cache misses" column or a --misses report in
ccusage, I would be glad to port the attribution logic; the reader and the inference rules
are about 300 lines with tests.
Activity
pullfrog commentedon Sep 26, 2026
github-actions commentedon Sep 26, 2026
Pullfrog triage: priority:low
Kind: feature request
Maintenance fit: excluded
Confidence: high
Requests a new cache-misses column or report using diagnostics cache_miss_reason. This is a new presentation surface, not a fix for incorrect reporting, with no maintainer endorsement, so it is an excluded feature request with low priority.
Decision: closed by the contribution gate.
ryoppippi commentedon Sep 27, 2026
Thanks for the detailed write-up and for building
cachemiss! The data is definitely real: I checked my own logs andmessage.diagnostics.cache_miss_reasonshows up on a couple thousand assistant records across all six reason types you listed.That said, we're going to keep this out of ccusage for now, for a few reasons:
--missesreport would add a new table/JSON contract that we'd need to keep stable long-term.diagnosticsis an internal Claude Code transcript field, so its shape can change or disappear without notice.If you'd like more visibility for
cachemiss, a PR adding it todocs/guide/community-projects.mdwould be very welcome. Thanks again!