Home / Reference / Environment variables

`CLAUDE_CODE_RESUME_SOURCE_ALIVE`

env in the build JSON

A Claude Code environment variable, read out of the shipped bundle. It has been in the build since v2.1.212, including the newest one read.

Set by Claude Code in the environment of a background session it launches, as <sessionId>|<boundary>[|<parentSessionId>] or a bare boundary value (1 when there is none), apparently to mark that the session it was forked from is still alive. On resume the child parses it and, when it is a bare value or names the resumed session or its parent, changes how the transcript is loaded; when the boundary is an ISO timestamp and a session ID is present, the job record gains forkSourceAlive, forkBoundaryAt and forkSessionId.

Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.286 bundle, and it can be wrong.

First seen v2.1.212 16 Jul 2026

Last seen v2.1.309 22 Oct 2026

Builds86 / 150on this box, as of v2.1.309

Written about — no changelog entry names it

v2.1.212in the build not in the build never minedv2.1.309

In the changelogs

No changelog entry here has ever named it. That is a statement about what has been written, not about the name: it has been in the build since v2.1.212 without anybody writing a line about it.

First cited

No release's published evidence quotes this name. The ledger indexes the Evidence lines of every changelog on this site, so this says nobody here has ever quoted it; it says nothing about how old the name is.

Presence across releases

BuildsHow manyDatesReading

v2.1.212 – v2.1.30986 builds16 Jul 2026 → 22 Oct 2026 ◆in the build

Build by build

One row per release since the first build this name was read out of. Absent means the build was read and the name was not in it, never mined means no bundle for that release was ever archived, and a declared type or a default is only ever what that release's own bundle stated.

BuildDateStateThe record behind it

v2.1.21216 Jul 2026·addedverdict: added · str

v2.1.21317 Jul 2026·presentverdict: present · str

v2.1.21418 Jul 2026·presentverdict: present · str

v2.1.21519 Jul 2026·presentverdict: present · str

v2.1.21620 Jul 2026·presentverdict: present · str

v2.1.21721 Jul 2026·presentverdict: present · str

v2.1.21822 Jul 2026·presentverdict: present · str

v2.1.21924 Jul 2026·presentverdict: present · str

v2.1.22024 Jul 2026·presentverdict: present · str

v2.1.2213 Aug 2026·presentverdict: present · str

v2.1.2224 Aug 2026·presentverdict: present · str

v2.1.2235 Aug 2026·presentverdict: present · str

v2.1.2247 Aug 2026·presentverdict: present · str

v2.1.2257 Aug 2026·presentverdict: present · str

v2.1.2268 Aug 2026·presentverdict: present · str

v2.1.22710 Aug 2026·presentverdict: present · str

v2.1.22811 Aug 2026·presentverdict: present · str

v2.1.22912 Aug 2026·presentverdict: present · str

v2.1.23113 Aug 2026·presentverdict: present · str

v2.1.23213 Aug 2026·presentverdict: present · str

v2.1.23314 Aug 2026·presentverdict: present · str

v2.1.23417 Aug 2026·presentverdict: present · str

v2.1.23518 Aug 2026·presentverdict: present · str

v2.1.23619 Aug 2026·presentverdict: present · str

v2.1.23719 Aug 2026·presentverdict: present · str

v2.1.23820 Aug 2026·presentverdict: present · str

v2.1.23921 Aug 2026·presentverdict: present · str

v2.1.24022 Aug 2026·presentverdict: present · str

v2.1.24122 Aug 2026·presentverdict: present · str

v2.1.24224 Aug 2026·presentverdict: present · str

v2.1.24324 Aug 2026·presentverdict: present · str

v2.1.24525 Aug 2026·presentverdict: present · str

v2.1.24625 Aug 2026·presentverdict: present · str

v2.1.24726 Aug 2026·presentverdict: present · str

v2.1.24827 Aug 2026·presentverdict: present · str

v2.1.25027 Aug 2026·presentverdict: present · str

v2.1.25128 Aug 2026·presentverdict: present · str

v2.1.25231 Aug 2026·presentverdict: present · str

v2.1.2571 Sep 2026·presentverdict: present · str

v2.1.2581 Sep 2026·presentverdict: present · str

v2.1.2592 Sep 2026·presentverdict: present · str

v2.1.2603 Sep 2026·presentverdict: present · str

v2.1.2614 Sep 2026·presentverdict: present · str

v2.1.2636 Sep 2026·presentverdict: present · str

v2.1.2658 Sep 2026·presentverdict: present · str

v2.1.2668 Sep 2026·presentverdict: present · str

v2.1.2679 Sep 2026·presentverdict: present · str

v2.1.26810 Sep 2026·presentverdict: present · str

v2.1.26911 Sep 2026·presentverdict: present · str

v2.1.27012 Sep 2026·presentverdict: present · str

v2.1.27114 Sep 2026·presentverdict: present · str

v2.1.27214 Sep 2026·presentverdict: present · str

v2.1.27315 Sep 2026·presentverdict: present · str

v2.1.27416 Sep 2026·presentverdict: present · str

v2.1.27517 Sep 2026·presentverdict: present · str

v2.1.27618 Sep 2026·presentverdict: present · str

v2.1.27718 Sep 2026·presentverdict: present · str

v2.1.27819 Sep 2026·presentverdict: present · str

v2.1.28022 Sep 2026·presentverdict: present · str

v2.1.28123 Sep 2026·presentverdict: present · str

v2.1.28224 Sep 2026·presentverdict: present · str

v2.1.28325 Sep 2026·presentverdict: present · str

v2.1.28428 Sep 2026·presentverdict: present · str

v2.1.28529 Sep 2026·presentverdict: present · str

v2.1.28630 Sep 2026·presentverdict: present · str

v2.1.2871 Oct 2026·presentverdict: present · str

v2.1.2882 Oct 2026·presentverdict: present · str

v2.1.2893 Oct 2026·presentverdict: present · str

v2.1.2905 Oct 2026·presentverdict: present · str

v2.1.2916 Oct 2026·presentverdict: present · str

v2.1.2926 Oct 2026·presentverdict: present · str

v2.1.2937 Oct 2026·presentverdict: present · str

v2.1.2948 Oct 2026·presentverdict: present · str

v2.1.2958 Oct 2026·presentverdict: present · str

v2.1.2969 Oct 2026·presentverdict: present · str

v2.1.29914 Oct 2026·presentverdict: present · str

v2.1.30014 Oct 2026·presentverdict: present · str

v2.1.30115 Oct 2026·presentverdict: present · str

v2.1.30216 Oct 2026·presentverdict: present · str

v2.1.30318 Oct 2026·presentverdict: present · str

v2.1.30419 Oct 2026·presentverdict: present · str

v2.1.30520 Oct 2026·presentverdict: present · str

v2.1.30621 Oct 2026·presentverdict: present · str

v2.1.30721 Oct 2026·presentverdict: present · str

v2.1.30822 Oct 2026·presentverdict: present · str

v2.1.30922 Oct 2026·presentverdict: present · str

Read out of the published npm bundle release by release, and out of Anthropic's own documentation as this site captured it. Nothing on this page is a description anybody here wrote about what the environment variable does. All environment variables.

Names beside it

Every environment variable in the inventory starting claude_code_resume, up to twelve of them.

CLAUDE_CODE_RESUME_FROM_SESSION v2.1.138
Child worker processes no longer inherit your session id, resume prompt or auth handles.
CLAUDE_CODE_RESUME_INTERRUPTED_TURN v2.1.138
Resuming a turn interrupted by shutdown now correctly sees the tool call as still pending instead of faked-answered.
CLAUDE_CODE_RESUME_INTERRUPTED_TURN_MAX_AGE_MS v2.1.211
The staleness cutoff for auto-resuming an interrupted turn is now configurable, defaulting to 6 hours
CLAUDE_CODE_RESUME_PROMPT v2.1.140
Child worker processes no longer inherit your session id, resume prompt or auth handles.
CLAUDE_CODE_RESUME_REASON v2.1.268
New CLAUDE_CODE_RESUME_REASON env var labels why an interrupted turn was resumed
CLAUDE_CODE_RESUME_SESSIONSTART_HOOKS_WAIT_MS v2.1.296
Claude Code now reads three new environment variables: agent progress summaries, a sleep-compaction delay and a resume hook wait
CLAUDE_CODE_RESUME_SHOWS_CUT_OFF_CALLS v2.1.309
A new CLAUDE_CODE_RESUME_SHOWS_CUT_OFF_CALLS setting lets a resumed session show tool calls that were interrupted mid-turn
CLAUDE_CODE_RESUME_THRESHOLD_MINUTES v2.1.138
Minimum age in minutes of the last user or assistant message older than one minute before Claude Code offers the resume-return prompt with the choices compact, continue, dismiss and never. Default 70 when unset or not a number; 0 is taken literally and removes the age requirement. The prompt also needs tengu_gleaming_fair or tengu_gleaming_fair_reuse on, the user not having picked never, and the conversation at or above CLAUDE_CODE_RESUME_TOKEN_THRESHOLD.
CLAUDE_CODE_RESUME_TOKEN_THRESHOLD v2.1.138
Minimum estimated token count of the conversation before Claude Code offers the resume-return prompt with the choices compact, continue, dismiss and never. Default 100000 when unset or not a number; 0 is taken literally and removes the token requirement. The prompt also needs tengu_gleaming_fair or tengu_gleaming_fair_reuse on and the last message older than CLAUDE_CODE_RESUME_THRESHOLD_MINUTES.
CLAUDE_CODE_RESUME_TOLERATES_CONTEXT_APPENDS v2.1.242
Resuming can pick up an interrupted tool call, but only with two env vars set.
CLAUDE_CODE_RESUME_TOLERATES_CONTEXT_SEEDS v2.1.290
Setting CLAUDE_CODE_RESUME_TOLERATES_CONTEXT_SEEDS stops resume treating some final messages as an interrupted turn

Documentation pages 0

None of Anthropic's documentation pages this site has a copy of carries this name.