Source Intelligence

DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.212

GrowthBook Authenticated Feature Flag Fetch [Gradual Rollout]

Feature flag
tengu_gb_eval_authed_enable Not enough to say

Nothing here resolved what this flag was doing on this version, so nothing here should be read as on or off.

This account: no value returned · anonymous baseline: no value returned · compiled default in v2.1.212: on

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.212. It isn't a statement about your account. What a flag value here can and cannot tell you

GrowthBook feature flag evaluation can now use an authenticated endpoint (/api/eval-authed/) that attaches your auth headers, enabling per-user flag targeting. Falls back to the unauthenticated /api/eval endpoint on any error.

Details
  • Controlled by tengu_gb_eval_authed_enable (default: false).
  • When enabled, GrowthBook's fetchRemoteEvalCall hook is monkey-patched once at startup (idempotent — a boolean sentinel prevents double-installation). Subsequent feature-flag evaluations POST to <host>/api/eval-authed/<clientKey> instead of the standard <host>/api/eval/<clientKey>.
  • Auth headers are sourced from the user's current authentication state via getAuthHeaders(): an OAuth access token adds Authorization: Bearer <token> and the anthropic-beta header; an API key adds x-api-key; gateway or third-party provider sessions attach no auth headers, leaving the request functionally unauthenticated despite hitting the authed endpoint.
  • On non-2xx response: logs "GrowthBook eval-authed returned non-ok; falling back to /api/eval" and re-runs the call via the original unauthenticated path.
  • On network or exception error: logs "GrowthBook eval-authed fetch threw; falling back to /api/eval" and falls back similarly.
Evidence

"GrowthBook eval-authed fetch threw; falling back to /api/eval" (search for "/api/eval-authed/")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

See this entry in the whole of v2.1.212 →