**Claude only.** On the Respawn tab, above the loop controls.
Claude Code bills a turn against the cached conversation while that cache is warm, and lets the cache expire after a fixed idle time: one hour on a subscription within plan usage, five minutes on an API key, a cloud provider or extra-usage credits. The first turn after a longer break re-processes the whole context at the cache-write rate, which is why coming back to a big session after lunch costs more than the turns around it.
Claude Code 2.1.251 and newer reports the cache state on the statusline after every response, and Codeman's statusline exporter keeps it per session. The row shows **Warm until HH:MM** with the lifetime and the tokens that would be re-cached if it went cold, or **Cold** with the size of the re-cache the next turn pays. When Claude reports them it also shows the session's cache hit rate and the cause of the last cache miss (for example `ttl_expired_1h` or `tools_changed`), so a surprise miss has a reason next to it. If the conversation is compacted while it stays warm (Claude Code now does this on its own on large idle sessions, a manual `/compact` does it too, and so does a clearing of old tool results), the row notes **Context compacted at HH:MM** until the next turn: Claude Code reports no re-cache size until then. None of this raises an alert. The row refreshes live and flips to cold on its own when the lifetime passes, and the last state is kept across a Codeman restart so it is not blank until the session's next turn. Sessions without a statusline of their own also get a short `cache:until HH:MM` or `cache:cold` group in the terminal footer. The readout rides the plan usage chip's telemetry collection, which is on by default on desktop.
**Keep the cache warm while idle** is the switch under the readout. With it on, Codeman sends a one-line keep-alive turn (`Codeman cache keep-alive: no action needed, reply with just "ok".`) about five minutes before the cache would expire. Claude answers `ok`, the request refreshes the cache for another hour, and your next real prompt reads the conversation from cache instead of re-processing it. Measured on sessions of about 110k tokens, the keep-alive cost a cache read plus a one-word reply, a small fraction of the re-write it prevented.
It only fires when there is nothing else going on: the session is idle with an empty prompt (Claude Code's greyed-out prompt suggestion counts as empty), no permission or question dialog is open, nobody has typed in the last few minutes, no respawn loop, Ralph loop or waiting agent is driving the session, and the session is not paused on a usage limit. If any of those hold it waits a minute and looks again, and gives up a minute before the expiry rather than race it; a keep-alive that could not be sent is retried the same way. It also stops by itself a few hours after your last prompt (**Keep warm for at most**, under App Settings → System → Automation, default 2 hours), because the saving is concentrated in gaps of one to four hours and an overnight run of hourly keep-alives would cost more than the single cold turn in the morning. It stands down for the rest of a gap once the context has been compacted. The readout's Status line gains a `Keep-alive:` line that says what it is doing: the next keep-alive and when the window closes, waiting and why, sent at a time with a count, or stopped and why. A session started without the cache readout (Plan Usage off at launch, a workspace with its own statusLine, a remote or Docker session) cannot be kept warm: the switch is greyed out and cannot be switched on (one that is already on can still be switched off), and the Status line says why.
Recent Claude Code builds can compact a large idle session on their own shortly before the cache expires, which would leave only a summary to keep warm. So a session **started** with keep-warm on also launches with Claude Code's idle compaction switched off (Claude Code 2.1.290 or newer); Codeman then owns the idle policy for it. A session you switch on after it started is still kept warm, but Claude Code may compact it first until its next launch, and the Status line says so; one you switch off keeps Claude Code's idle compaction off until its next launch, and the Status line says that too. Sessions with keep-warm off launch exactly as before.
**Keep prompt caches warm** in the same Automation group is the default for sessions that have not chosen on their Respawn tab; the per-session switch always wins. A session another agent started (a worker) does not follow the default: most workers are never prompted again once they report done, so turn it on for one by hand if you will come back to it. The keep-alive turn is Codeman's, not yours: it does not restart the **Keep warm for at most** window, does not rename a tab, Read My Mind ignores it, and the response it ends with raises no alert, toast, push or webhook, nor a row in the Away digest or the session's Summary. It never clears an alert that was already waiting for you. It is refused on the five-minute cache lifetime, which is what an API key, a cloud provider or extra-usage credits get; a session on an API key can ask Claude Code for the hour with `CLAUDE_CODE_PROMPT_CACHE_TTL=1h` in its environment overrides.
its own app-server, and the Copilot quota from a read-only request to `api.github.com` every
10 minutes with Copilot's own token (on by default; Plan Usage Limits off stops it). Known limit: sessions inside a Docker case do not feed the chip yet.
