Summary

Clean, well-scoped fix for issue #1693. It correctly identifies that uv's bundled webpki roots can't validate a corporate MITM proxy's CA, that the resulting UnknownIssuer error masquerades as a transient "Failed to fetch", and that the right remedy is a --native-tls retry against the OS trust store. The detector is checked before the transient-retry path so it doesn't burn all three attempts on the same doomed roots — the exact failure mode the PR description calls out. Code, comments, tests, and the actionable error message all line up. The one thing worth knowing: there's a narrow ordering gap where the --native-tls retry can be skipped entirely (details below), but it won't bite the real-world case this PR targets.

Issues Found

🟢 --native-tls retry is skipped if the TLS signature first appears on the final attempt (backend-installer.cjs:1232)

The TLS branch sets useNativeTls = true and continues, which consumes a loop iteration rather than re-running in place. If attempts 1–2 fail for genuinely transient reasons and the UnknownIssuer signature only surfaces on attempt 3 (INSTALL_MAX_ATTEMPTS), the continue increments past the loop bound and the --native-tls attempt never executes — the install throws with the (correct) TLS suggestion, but the actual retry the PR promises didn't happen.

In practice a TLS-intercepting proxy fails deterministically from attempt 1, so this is unlikely to ever fire — hence minor, not blocking. If you want to close it cleanly, gate the loop bound so a not-yet-tried --native-tls always gets one real attempt, e.g.:

  for (let attempt = 1; attempt <= INSTALL_MAX_ATTEMPTS || (useNativeTls && !nativeTlsAttempted); attempt++) {

(with a nativeTlsAttempted flag set when the native-TLS run actually executes) — or simply re-run inline instead of continue. Your call; the current behavior is acceptable for the targeted scenario.

🟢 Consider noting the redundant native-TLS retries via the transient path (backend-installer.cjs:1245)

Once useNativeTls is set, a subsequent TLS failure still matches isTransientNetworkError (it wraps in "Failed to fetch"), so the remaining attempts re-run with --native-tls under the transient backoff. That's harmless — arguably a bonus extra try — but the "retry once with --native-tls" comment at line 1230 slightly undersells it. Not worth changing code over; just flagging that the comment and runtime behavior diverge a little.

Strengths

• Correct root-cause framing. The ordering — check isTlsCertError before isTransientNetworkError — is the crux of the fix, and the comments at backend-installer.cjs:1228 and 497–522 explain why (the transient matcher also catches this) rather than restating the code. This is exactly the WHY-comment style CLAUDE.md asks for.
• Fails loudly with an actionable message. The new else if (isTlsCertError(output)) branch names what failed (untrusted proxy cert), what the user should do (ask IT to install the CA in the system store), and where to go next (quickstart link) — matches the "actionable errors name three things" rule, no silent fallback.
• Tests target the real signature. isTlsCertError is exported and covered against the exact issue [Bug]: GAIA install fails on update #1693 UnknownIssuer block plus common phrasings, with negative cases asserting plain network/dependency failures don't match. Honest about its limits, too — the PR flags that automated checks can't reproduce a live MITM proxy and asks for manual validation.

Verdict

Approve. No blocking issues. The two minor notes are optional polish; the change is correct, well-tested, and safe to merge for the scenario it targets. Worth honoring the PR's own call-out for one manual validation on a real (or simulated) TLS-intercepting proxy before relying on it in the field.

🟡 backend-installer.cjs:1272 — error message can claim --native-tls was tried when it wasn't

If the TLS error only surfaces on the last attempt (e.g. attempts 1–2 failed with transient errors and used up INSTALL_MAX_ATTEMPTS - 1 slots), the !useNativeTls && isTlsCertError(...) branch fires, sets useNativeTls = true, and continues — but the loop counter has already hit INSTALL_MAX_ATTEMPTS, so the loop exits without ever running the --native-tls retry. The failure path then shows "GAIA retried with the OS certificate store and it still failed", which is false.

Fix: gate the user-facing message on whether native-TLS was actually executed:

} else if (isTlsCertError(output)) {
  suggestion = useNativeTls
    ? "PyPI's certificate isn't trusted on this network — usually a corporate proxy. " +
      "GAIA retried with the OS certificate store and it still failed. " +
      "Ask IT to install the proxy's root CA in your system's trusted certificate store, then relaunch GAIA. " +
      "See https://amd-gaia.ai/quickstart#cli-install"
    : "PyPI's certificate isn't trusted on this network — usually a corporate proxy. " +
      "Try rerunning; if that also fails, ask IT to install the proxy's root CA. " +
      "See https://amd-gaia.ai/quickstart#cli-install";
}

The happy path (TLS error on attempt 1, native-tls succeeds or gives a clear second failure) is unaffected.

Addressed the review feedback in d1c39f5 — the ordering gap where --native-tls could be skipped.

The TLS branch flips useNativeTls and continues, consuming a loop iteration. If the UnknownIssuer signature only surfaced on the final attempt (two transient failures first), the loop exited without ever running the retry — and the failure message still claimed GAIA had retried against the OS trust store. Fix:

• Extend the loop bound by one when a not-yet-run --native-tls is pending (nativeTlsAttempted flag), so the promised retry always gets one real attempt.
• Gate the "GAIA retried with the OS certificate store" line on whether the retry actually executed, so the message can't claim a retry that didn't happen.

Traced the edge case (transient×2 → TLS on attempt 3 now runs a real --native-tls attempt) and confirmed the extension fires at most once (no infinite loop). The predicate suite still passes; the install loop itself isn't exported, so it has no direct unit test without refactoring the bootstrap function.