What it is
New sandbox and approval flow for project hooks run read-only during cloud/remote sessions
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.277.
Presence across releases
1Build by build
3One 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.
First cited
1The earliest release whose published evidence quoted tengu_violin_peg was v2.1.277, 18 Sep 2026. That is the oldest release this project wrote about it, so it is a floor on the name's age and not the release that introduced it. It is not a presence reading: which builds carried the name is the table above.
Gate readings
1| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.277 read on another version | Off by default, switched on for this account | on | on | off |
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
3| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| this account | on | 2026-09-16T17:15:04Z | 2026-09-23T08:55:05Z | v2.1.273 to v2.1.280 |
| anonymous | on | 2026-09-16T16:35:04Z | 2026-09-23T08:55:05Z | v2.1.273 to v2.1.280 |
| anonymous | off | 2026-09-16T16:30:05Z | 2026-09-16T16:30:05Z | v2.1.273 |
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.
Names beside it
Every feature flag in the inventory starting tengu_violin, up to twelve of them.
tengu_violin_Remote sessions started from the desktop app now need a second flag as well. never mined
tengu_violin_amatiSettings pushed from the control channel are checked before they can change plugin forwarding, and refusals are logged. v2.1.239
tengu_violin_bridgepinNew display styles for background tool results and for repository-trust folder-wait refusals v2.1.277
tengu_violin_chinrestNotices for shared/served folders are now deduplicated and capped instead of fired one by one never mined
tengu_violin_fretHeadless and desktop cloud sessions in auto or bypass mode now ask once whether Claude may act unattended, and the answer is saved. v2.1.259
tengu_violin_muteScaffolding to mute and unmute served tools has landed, with state labels and a periodic timer, but nothing calls it. v2.1.257
tengu_violin_pegboxRemote sessions started from the desktop app now need a second flag as well. never mined
tengu_violin_plan_classifierA new flag will control whether plan mode gets classifier-based permission checks v2.1.267
tengu_violin_scrollClaude Code adds an unreleased one-shot 'reannounce' request for remote tools, off by default v2.1.280
tengu_violin_soundpostDirectory sync gains a pre-attach safety check to verify a checkout can attach cleanly, behind a new gate v2.1.277
tengu_violin_speculative_classifierTwo new internal feature gates appeared: tengu_unified_waterfall and tengu_violin_speculative_classifier, the latter currently stubbed to always return false never mined
tengu_violin_stradRemote sessions could inherit your local permission mode and effort level, but no value is compiled in. v2.1.238
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.