tengu_print_engine_loop
A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.247 and was gone by v2.1.257.
The env var controlling print and engine loop behavior was renamed to CLAUDE_CODE_HUMBLE_HAMMOCK and still defaults to off.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.257.
In the changelogs
1Releases whose published page names tengu_print_engine_loop.
-
v2.1.257
Renamed/relaunched print-engine-loop flag as 'humble hammock'
The env var controlling print and engine loop behavior was renamed to CLAUDE_CODE_HUMBLE_HAMMOCK and still defaults to off.
found in this entry's text, gate cited by this entry
Gate readings
1| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.257 read on another version | On for this account, and not off by default | on | on | no gate table built for this version |
Two arms, because they disagree: this account is the one account this site reads and anonymous is a baseline with no identity attached. A reading says nothing about your account, and off cannot rule out a rollout both readings sit outside of. What these readings can and cannot show.
Flag server, over time
16| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| anonymous | on | 2026-10-17T05:30:04Z | 2026-11-12T07:05:04Z | v2.1.302 to v2.1.322 |
| this account | on | 2026-09-10T21:47:12Z | 2026-11-12T07:05:04Z | v2.1.268 to v2.1.322 |
| anonymous | no longer carried | 2026-10-17T05:25:57Z | 2026-10-17T05:25:57Z | v2.1.302 |
| anonymous | on | 2026-08-28T16:45:05Z | 2026-10-17T05:10:04Z | v2.1.246 to v2.1.302 |
| this account | no longer carried | 2026-09-10T21:46:45Z | 2026-09-10T21:46:45Z | v2.1.268 |
| this account | on | 2026-09-08T20:36:15Z | 2026-09-10T17:40:05Z | v2.1.263 to v2.1.267 |
| this account | no longer carried | 2026-09-08T20:34:58Z | 2026-09-08T20:34:58Z | v2.1.265 |
| this account | on | 2026-09-06T02:40:05Z | 2026-09-08T18:45:05Z | v2.1.261 to v2.1.263 |
| this account | no longer carried | 2026-09-06T02:36:19Z | 2026-09-06T02:36:19Z | v2.1.263 |
| this account | on | 2026-08-28T18:40:05Z | 2026-09-06T01:55:04Z | v2.1.246 to v2.1.261 |
| this account | off | 2026-08-28T16:20:16Z | 2026-08-28T17:45:05Z | v2.1.246 |
| anonymous | off | 2026-08-25T18:10:05Z | 2026-08-28T16:25:09Z | v2.1.233 to v2.1.246 |
| this account | on | 2026-08-28T16:15:43Z | 2026-08-28T16:15:43Z | v2.1.251 |
| this account | off | 2026-08-28T00:06:06Z | 2026-08-28T15:25:06Z | v2.1.250 to v2.1.246 |
| this account | on | 2026-08-27T23:46:12Z | 2026-08-27T23:46:12Z | v2.1.248 |
| this account | off | 2026-08-25T19:25:04Z | 2026-08-27T22:35:37Z | v2.1.233 to v2.1.246 |
One row per unbroken stretch of one reading, newest first, from snapshots taken every twenty-five minutes or so. No longer carried is not off: it means the flag server stopped returning the gate at all, which is what a retired experiment looks like. The version column is what was installed when the reading was taken, not what caused it.
First cited
0No 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
2Build by build
64One 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.
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 feature flag does. All feature flags.