tengu_quiet_hopcroft
A Claude Code feature flag, read out of the shipped bundle. No mined inventory carries it: everything below comes from what this site has written about it.
When a hook cannot check a call, Claude Code now blocks the call instead of letting it through
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.288.
In the changelogs
2Releases whose published page names tengu_quiet_hopcroft.
-
v2.1.288
A call is blocked when a hook cannot check it
When a hook cannot check a call, Claude Code now blocks the call instead of letting it through
gate cited by this entry
-
v2.1.288
Tool calls are blocked when Claude Code can't prepare or match their hooks
If Claude Code can't work out which hooks apply to a tool call, or can't package the hook input, it now blocks the call with an error
gate cited by this entry
Gate readings
1| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.288 read on another version | Off in both readings | off | off | 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
2| Read as | Reading | From | Until | Version installed |
|---|---|---|---|---|
| this account | off | 2026-10-02T15:15:06Z | 2026-10-02T21:40:05Z | v2.1.287 to v2.1.288 |
| anonymous | off | 2026-10-02T14:50:07Z | 2026-10-02T21:40:05Z | v2.1.287 to v2.1.288 |
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
1The earliest release whose published evidence quoted tengu_quiet_hopcroft was v2.1.288, 2 Oct 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 below.
Presence across releases
0The miner has never read a build containing this name. It is here because a changelog entry of ours names it, which is evidence that it existed and not evidence of which releases carried it. The inventory starts at v2.1.138 and everything older than that was never mined.
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.