fix(auxiliary): apply review fixes to #36043 — guard named-custom routing, drop dead key assignment, tighten Palantir host match

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.

agent/anthropic_adapter.py

@@ -534,8 +534,9 @@ def _requires_bearer_auth(base_url: str | None) -> bool:
 
     Some third-party /anthropic endpoints implement Anthropic's Messages API but
     require Authorization: Bearer instead of Anthropic's native x-api-key header.
-    MiniMax's global and China Anthropic-compatible endpoints, and Azure AI
-    Foundry's Anthropic-style endpoint follow this pattern.
+    MiniMax's global and China Anthropic-compatible endpoints, Azure AI
+    Foundry's Anthropic-style endpoint, and Palantir Foundry's LLM proxy
+    follow this pattern.
     """
     normalized = _normalize_base_url_text(base_url)
     if not normalized:
@@ -544,7 +545,11 @@ def _requires_bearer_auth(base_url: str | None) -> bool:
     return (
         normalized.startswith(("https://api.minimax.io/anthropic", "https://api.minimaxi.com/anthropic"))
         or "azure.com" in normalized
-        or "palantirfoundry" in normalized
+        # Palantir Foundry LLM proxy (<org>.palantirfoundry.com/api/v2/llm/proxy/anthropic)
+        # rejects x-api-key with 401 and requires Authorization: Bearer.
+        # Hostname match (not substring) so e.g. evil.com/palantirfoundry
+        # paths don't trigger Bearer auth.
+        or base_url_host_matches(normalized, "palantirfoundry.com")
     )
 
 

agent/auxiliary_client.py

@@ -4392,17 +4392,32 @@ def _resolve_auto(
             explicit_api_key = runtime_api_key or None
         elif main_provider.startswith("custom:"):
             # Named custom provider (custom_providers / providers dict entry).
-            # KEEP the full ``custom:<name>`` so resolve_provider_client lands in
-            # the named-custom-provider arm — that arm honours the entry's
-            # api_mode (e.g. anthropic_messages → AnthropicAuxiliaryClient,
-            # avoiding the /anthropic→/v1 rewrite that 404s against proxies
-            # like Palantir Foundry's Anthropic surface).  Do NOT collapse to
-            # plain "custom"; that path strips /anthropic and routes through
-            # OpenAI chat.completions.
-            resolved_provider = main_provider
-            # base_url / api_key come from the named entry itself — leave the
-            # explicit_* overrides unset so the named arm reads them from config.
-            if runtime_api_key:
+            _has_named_entry = False
+            try:
+                from hermes_cli.runtime_provider import _get_named_custom_provider
+                _has_named_entry = _get_named_custom_provider(main_provider) is not None
+            except ImportError:
+                pass
+            if _has_named_entry:
+                # KEEP the full ``custom:<name>`` so resolve_provider_client
+                # lands in the named-custom-provider arm — that arm honours the
+                # entry's api_mode (e.g. anthropic_messages →
+                # AnthropicAuxiliaryClient, avoiding the /anthropic→/v1 rewrite
+                # that 404s against proxies like Palantir Foundry's Anthropic
+                # surface).  Do NOT collapse to plain "custom"; that path
+                # strips /anthropic and routes through OpenAI chat.completions.
+                # base_url and api_key come from the named entry itself, so
+                # leave the explicit_* overrides unset.
+                resolved_provider = main_provider
+                explicit_base_url = None
+            elif runtime_base_url:
+                # Config-less named custom provider (#34777): the entry only
+                # exists in the live runtime, so collapse to the anonymous
+                # custom arm with the runtime endpoint + key.
+                resolved_provider = "custom"
+                explicit_base_url = runtime_base_url
+                explicit_api_key = runtime_api_key or None
+            elif runtime_api_key:
                 explicit_api_key = runtime_api_key
         elif runtime_api_key:
             # Pin auxiliary to the same api_key as the active main chat session

tests/agent/test_anthropic_adapter.py

@@ -201,6 +201,44 @@ class TestBuildAnthropicClient:
             betas = kwargs["default_headers"]["anthropic-beta"]
             assert "context-1m-2025-08-07" in betas
 
+    def test_palantir_foundry_anthropic_endpoint_uses_bearer_auth(self):
+        """Palantir Foundry's LLM proxy requires Authorization: Bearer.
+
+        Regression test for PR #36043: Palantir's
+        ``<org>.palantirfoundry.com/api/v2/llm/proxy/anthropic`` endpoint
+        rejects x-api-key with 401 — the SDK must be built with auth_token.
+        """
+        with patch("agent.anthropic_adapter._anthropic_sdk") as mock_sdk:
+            build_anthropic_client(
+                "foundry-secret-123",
+                base_url="https://acme.palantirfoundry.com/api/v2/llm/proxy/anthropic",
+            )
+            kwargs = mock_sdk.Anthropic.call_args[1]
+            assert kwargs["auth_token"] == "foundry-secret-123"
+            assert "api_key" not in kwargs
+
+    def test_palantir_bearer_auth_matches_hostname_not_substring(self):
+        """The palantirfoundry check must be a hostname match, not a loose
+        substring match — a URL merely *containing* the string (path segment,
+        lookalike domain) must not trigger Bearer auth."""
+        from agent.anthropic_adapter import _requires_bearer_auth
+
+        # Real Foundry hosts (org subdomains) → Bearer.
+        assert _requires_bearer_auth(
+            "https://acme.palantirfoundry.com/api/v2/llm/proxy/anthropic"
+        ) is True
+        assert _requires_bearer_auth("https://palantirfoundry.com/anthropic") is True
+        # Substring false-positives → x-api-key (default).
+        assert _requires_bearer_auth(
+            "https://evil.example.com/palantirfoundry/anthropic"
+        ) is False
+        assert _requires_bearer_auth(
+            "https://palantirfoundry.com.evil.example/anthropic"
+        ) is False
+        assert _requires_bearer_auth(
+            "https://notpalantirfoundry.com/anthropic"
+        ) is False
+
     def test_disables_sdk_retries_for_api_key(self):
         """#26293: the SDK's default max_retries=2 ignores Retry-After and
         double-retries inside hermes's outer loop. We delegate retry entirely

tests/agent/test_set_runtime_main_custom_provider.py

@@ -224,3 +224,72 @@ class TestResolveAutoCustomEndToEnd:
             assert base and base.rstrip("/") == "https://withcfg.example/v1"
         finally:
             mod.clear_runtime_main()
+
+    def test_named_custom_anthropic_messages_keeps_full_name_and_url(
+            self, tmp_path, monkeypatch):
+        """PR #36043: a ``custom:<name>`` main provider whose config entry
+        declares ``api_mode: anthropic_messages`` must reach the
+        named-custom-provider arm of resolve_provider_client — NOT the
+        anonymous-custom arm, whose ``_to_openai_base_url`` rewrite strips a
+        trailing ``/anthropic`` into ``/v1`` and 404s against proxies like
+        Palantir Foundry's Anthropic surface.  The resulting client must be an
+        AnthropicAuxiliaryClient pointed at the ORIGINAL /anthropic URL."""
+        import agent.auxiliary_client as mod
+
+        for var in ("OPENROUTER_API_KEY", "NOUS_API_KEY", "OPENAI_API_KEY",
+                    "OPENAI_BASE_URL"):
+            monkeypatch.delenv(var, raising=False)
+        hermes_home = tmp_path / ".hermes"
+        hermes_home.mkdir()
+        proxy_base = "https://acme.palantirfoundry.com/api/v2/llm/proxy/anthropic"
+        (hermes_home / "config.yaml").write_text(
+            "model:\n"
+            "  default: claude-4-6-opus\n"
+            "  provider: 'custom:palantir'\n"
+            "  base_url: ''\n"
+            "custom_providers:\n"
+            "  - name: palantir\n"
+            f"    base_url: '{proxy_base}'\n"
+            "    model: claude-4-6-opus\n"
+            "    api_key: foundry-token\n"
+            "    api_mode: anthropic_messages\n"
+        )
+        monkeypatch.setenv("HERMES_HOME", str(hermes_home))
+
+        mod.clear_runtime_main()
+        try:
+            # The live runtime carries the same base_url the main agent uses —
+            # the regression collapsed the provider to bare "custom" whenever a
+            # runtime base_url was present, which routed here through the
+            # OpenAI-wire /anthropic→/v1 rewrite.
+            mod.set_runtime_main(
+                "custom:palantir",
+                "claude-4-6-opus",
+                base_url=proxy_base,
+                api_key="foundry-token",
+                api_mode="anthropic_messages",
+            )
+            client, resolved = mod.resolve_provider_client("auto", None)
+            assert client is not None, (
+                "custom:<name> with anthropic_messages entry resolved to None"
+            )
+            assert resolved == "claude-4-6-opus"
+            assert client.__class__.__name__ == "AnthropicAuxiliaryClient", (
+                f"expected AnthropicAuxiliaryClient, got {client.__class__.__name__}"
+                " — the custom:<name> main provider was collapsed to the"
+                " anonymous-custom OpenAI-wire arm (PR #36043 regression)"
+            )
+            # The original /anthropic URL must survive — no /v1 rewrite.
+            assert getattr(client, "base_url", "").rstrip("/") == proxy_base
+
+            # Wiring check: _resolve_auto must hand the FULL custom:<name>
+            # string to resolve_provider_client, with no explicit_base_url
+            # override (the named arm reads base_url/api_key from config).
+            with patch.object(mod, "resolve_provider_client") as mock_resolve:
+                mock_resolve.return_value = (MagicMock(), "claude-4-6-opus")
+                mod._resolve_auto(main_runtime=None)
+            mock_resolve.assert_called_once()
+            assert mock_resolve.call_args.args[0] == "custom:palantir"
+            assert mock_resolve.call_args.kwargs["explicit_base_url"] is None
+        finally:
+            mod.clear_runtime_main()