hermes auth add anthropic fails 100% at token exchange with HTTP 429 while
Claude Code /login succeeds through the same client_id/redirect/scope. The
discriminator is the User-Agent on the /v1/oauth/token request.
Verified live against platform.claude.com (throwaway code, nothing burned):
claude-code/2.1.200 (external, cli) -> 429 rate_limit (Hermes, blocked)
Mozilla/5.0 -> 429 rate_limit
axios/1.7.9 -> 400 invalid_grant (reached validation)
node / empty / SDK-style UAs -> 400 invalid_grant
Anthropic now rate-limits token-endpoint requests whose UA starts with
claude-code/ (the anti-abuse net for Max-sub-as-API-key). This is the same
prefix-block shape that #48534 first hit on claude-cli/, then #56263 dodged by
switching to claude-code/ — which held ~2 weeks and is now blocked too. Bumping
_CLAUDE_CODE_VERSION_FALLBACK cannot help; the gate is prefix-based.
Fix: shared _OAUTH_TOKEN_USER_AGENT (axios/) on the token endpoint only — the
two refresh POSTs (refresh_anthropic_oauth_pure) and the login exchange POST
(run_hermes_oauth_login_pure). The real Claude Code CLI exchanges the auth code
with a bare axios client, NOT its claude-code/ inference UA.
The INFERENCE client (build_anthropic_kwargs, /v1/messages) is deliberately left
on claude-code/ + x-app: cli — that fingerprint is required there and is NOT
throttled on the messages API. Two endpoints, opposite UA requirements.
Also isolate two _refresh_oauth_token tests from live ~/.claude creds and update
the UA regression tests to assert the split (token endpoint uses a
non-claude-code UA while inference keeps claude-code/).
Verified E2E: Hermes' own login path now returns 400 (past the 429 wall)
instead of 429, using the real _OAUTH_TOKEN_USER_AGENT constant against the live
platform.claude.com token endpoint.
Salvaged from #57922 (authorize-host + scope changes dropped as non-load-bearing;
they only add a redirect hop back to claude.ai and the UA fix alone clears 429).
Review follow-up on the anthropic_adapter batch salvage:
1. #52145 shipped no behavior test for the adjacency rewrite. Add
test_strips_tool_use_when_result_not_immediately_adjacent (a tool_use whose
result appears later but NOT in the immediately-following user message must
be stripped — the exact case the old global id-match got wrong) plus an
adjacent-pair control. Mutation-checked: reverting to a global match fails
the non-adjacent test.
2. test_token_refresh_ua_prefix was vacuous — it bound to _refresh_oauth_token
(a wrapper with no urllib.request.Request), so its assert never ran and it
did NOT guard the real refresh UA site. Retarget it at
refresh_anthropic_oauth_pure (:1048) with the header-scoped check. Mutation-
checked: reverting :1048 to claude-cli/ now fails it.
The salvaged test_token_exchange_ua_prefix did a naive whole-function substring
check for 'claude-cli/', which false-positives on an explanatory comment that
references the old (blocked) UA. Scope it to actual User-Agent header lines —
mirroring the sibling test_no_claude_cli_in_source — so a comment documenting
why claude-cli/ is avoided doesn't trip it. Mutation-checked: an actual
claude-cli/ UA header still fails the test.
Anthropic's OAuth endpoints 404 for the claude-cli/ User-Agent prefix. Switch
all three OAuth UA sites (build_anthropic_client, refresh_anthropic_oauth_pure,
run_hermes_oauth_login_pure) to the claude-code/ prefix Anthropic expects.
Salvaged from #51948.
Co-authored-by: DhivinX <20087092+DhivinX@users.noreply.github.com>
