tengu_bg_prewarm_burst_concurrency
A Claude Code feature flag, read out of the shipped bundle. It has been in the build since v2.1.206, including the newest one read.
What it is
Background session prewarm now checks the concurrency limit instead of the delay value.
Not Anthropic's. This is the line from the earliest changelog entry here that named it, v2.1.248.
Presence across releases
| Releases | Reading | Declared type | Default |
|---|---|---|---|
| 2.1.245 – 2.1.250 5 releases | never mined | — | — |
| 2.1.206 – 2.1.243 37 releases | in the build | — | number |
A row reading never mined is a release with no archived bundle behind it. Nothing was read out of it, so nothing here says whether the name was in it. A declared type or a default is only ever what that release's own bundle stated.
Gate readings
| Release | Resolved | This account | Anonymous | Compiled default |
|---|---|---|---|---|
| v2.1.248 | Not enough to say | no value returned | no value returned | not a boolean we can read |
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.
Changelog entries naming it
-
v2.1.248Prewarm burst guard tested the wrong value
Background session prewarm now checks the concurrency limit instead of the delay value.
gate cited by this entry
Documentation pages
None of Anthropic's documentation pages this site has a copy of carries this name.
Names beside it
Every feature flag in the inventory starting tengu_bg_prewarm_burst, up to twelve of them.
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.