Review follow-ups on the cherry-picked #36043 commit:
1. Guard the custom:<name> passthrough with a _get_named_custom_provider
lookup. The PR unconditionally kept the full custom:<name> string, which
broke config-less runtime custom providers (#34777 regression — entries
that exist only in the live runtime, not config.yaml): the named arm
found no entry and resolution fell through to Step 2. Now custom:<name>
only takes the named arm when a config entry actually exists; otherwise
it collapses to the anonymous-custom arm with the runtime endpoint,
preserving pre-PR behavior.
2. Drop the dead 'explicit_api_key = runtime_api_key' assignment (and its
misleading comment) in the named-entry branch. resolve_provider_client's
named-custom arm derives the key exclusively from the entry's
api_key/key_env and never reads explicit_api_key, so the assignment was
a no-op. Wiring precedence in was not justified: for a named custom
provider the runtime key IS the entry's key (set_runtime_main sources it
from the same config), so deletion is the honest option.
3. Tighten the Palantir Bearer-auth check from a loose substring match
('palantirfoundry' in normalized) to a hostname match via
base_url_host_matches(..., 'palantirfoundry.com'), so path segments or
lookalike domains containing the string no longer trigger Bearer auth.
Tests: named-custom anthropic_messages end-to-end routing (full name kept,
AnthropicAuxiliaryClient at the original /anthropic URL, no /v1 rewrite)
plus Palantir Bearer-auth positive and substring-false-positive cases.
Teknium
adb647269a