tengu_amber_astrolabe
A Claude Code feature flag, read out of the shipped bundle. It was in the build from v2.1.251 and was gone by v2.1.260.
Default false. One of the switches that add the autonomy_append system prompt section ("You are operating autonomously...": proceed with reversible actions without asking, report findings without applying a fix when the user is only asking, finish the work before ending the turn). The section is added when tengu_amber_sextant is on (default true) and either the current model's settings turn it on or this check passes; the check passes when CLAUDE_CODE_AMBER_ASTROLABE is set, the client data key of this name is true, or this flag is on.
Not Anthropic's. Written by Claude Opus 5.5 from reading the v2.1.259 bundle, and it can be wrong.
In the changelogs
1Releases whose published page names tengu_amber_astrolabe.
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v2.1.217
Four New Unnamed Feature Flags [In Development]
gate cited by this entry, found in this entry's text
Gate readings
0No release here has a gate table behind it for this flag. Most published releases have none at all: the readings exist only for versions the pipeline captured flag state on.
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
49One 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.