diff --git a/CHANGELOG.md b/CHANGELOG.md
index d048426b..63520be7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,12 @@
 
 ## [Unreleased]
 
+## [v0.51.681] — 2026-06-26 — Release YK (Anthropic shows in the model picker when configured via OAuth token)
+
+### Fixed
+
+- **The model picker now detects Anthropic when it's configured through an OAuth token instead of `ANTHROPIC_API_KEY`.** WebUI's env-fallback provider detection only looked for `ANTHROPIC_API_KEY`, so an Anthropic setup using OAuth token env vars (`ANTHROPIC_TOKEN` / `CLAUDE_CODE_OAUTH_TOKEN`, which the shared agent already accepts) fell out of parity and the provider didn't surface. The fallback now derives the Anthropic env-var set from the shared agent provider registry (with a built-in fallback list), and env values are stripped before the availability check so a whitespace-only token can't false-positive the provider. Thanks @rodboev. (#4995, fixes #4770)
+
 ## [v0.51.680] — 2026-06-26 — Release YJ (session-index rebuild can't be clobbered by a late worker)
 
 ### Fixed
diff --git a/api/config.py b/api/config.py
index c9732669..9c2ec86e 100644
--- a/api/config.py
+++ b/api/config.py
@@ -1171,6 +1171,37 @@ _PROVIDER_ALIASES = {
 }
 
 
+def _get_anthropic_fallback_env_vars() -> tuple[str, ...]:
+    """Read Anthropic auth env vars from the shared agent registry when available."""
+    fallback = (
+        "ANTHROPIC_API_KEY",
+        "ANTHROPIC_TOKEN",
+        "CLAUDE_CODE_OAUTH_TOKEN",
+    )
+    try:
+        from hermes_cli.auth import PROVIDER_REGISTRY
+
+        anthropic = (
+            PROVIDER_REGISTRY.get("anthropic")
+            if isinstance(PROVIDER_REGISTRY, dict)
+            else None
+        )
+        env_vars = getattr(anthropic, "api_key_env_vars", None)
+        if not env_vars:
+            return fallback
+
+        out = []
+        for _var in env_vars:
+            if not isinstance(_var, str):
+                continue
+            _normalized = _var.strip()
+            if _normalized and _normalized not in out:
+                out.append(_normalized)
+        return tuple(out) if out else fallback
+    except Exception:
+        return fallback
+
+
 def _resolve_provider_alias(name: str) -> str:
     """Return the canonical provider slug for *name*.
 
@@ -5687,8 +5718,9 @@ def get_available_models(*, prefer_cache: bool = False, force_refresh: bool = Fa
                 except Exception:
                     logger.debug("Failed to parse hermes env file")
             all_env = {**env_keys}
+            _anthropic_env_vars = _get_anthropic_fallback_env_vars()
             for k in (
-                "ANTHROPIC_API_KEY",
+                *_anthropic_env_vars,
                 "OPENAI_API_KEY",
                 "OPENROUTER_API_KEY",
                 "GOOGLE_API_KEY",
@@ -5707,10 +5739,10 @@ def get_available_models(*, prefer_cache: bool = False, force_refresh: bool = Fa
                 "AWS_ACCESS_KEY_ID",
                 "AWS_SECRET_ACCESS_KEY",
             ):
-                val = _thread_local_env_value(k)
+                val = _thread_local_env_value(k).strip()
                 if val:
                     all_env[k] = val
-            if all_env.get("ANTHROPIC_API_KEY"):
+            if any(all_env.get(env_var) for env_var in _anthropic_env_vars):
                 detected_providers.add("anthropic")
             if all_env.get("OPENAI_API_KEY"):
                 # hermes-agent registers its OPENAI_API_KEY/OPENAI_BASE_URL provider
diff --git a/tests/test_issue4770_anthropic_oauth_detection.py b/tests/test_issue4770_anthropic_oauth_detection.py
new file mode 100644
index 00000000..edebacfb
--- /dev/null
+++ b/tests/test_issue4770_anthropic_oauth_detection.py
@@ -0,0 +1,124 @@
+"""Regression tests for #4770 - Anthropic OAuth env vars in fallback detection."""
+
+import builtins
+import sys
+
+import api.config as config
+
+
+def _force_env_fallback(monkeypatch):
+    """Force get_available_models() into the env-based fallback branch."""
+    real_import = builtins.__import__
+    monkeypatch.delitem(sys.modules, "hermes_cli.auth", raising=False)
+    monkeypatch.delitem(sys.modules, "hermes_cli", raising=False)
+
+    def fake_import(name, globals=None, locals=None, fromlist=(), level=0):
+        if name in ("hermes_cli.models", "hermes_cli.auth"):
+            raise ImportError(name)
+        return real_import(name, globals, locals, fromlist, level)
+
+    monkeypatch.setattr(builtins, "__import__", fake_import)
+
+
+def _clear_provider_env(monkeypatch):
+    for key in (
+        "ANTHROPIC_API_KEY",
+        "ANTHROPIC_TOKEN",
+        "CLAUDE_CODE_OAUTH_TOKEN",
+        "OPENAI_API_KEY",
+        "OPENROUTER_API_KEY",
+        "GOOGLE_API_KEY",
+        "GEMINI_API_KEY",
+        "GLM_API_KEY",
+        "KIMI_API_KEY",
+        "DEEPSEEK_API_KEY",
+        "XIAOMI_API_KEY",
+        "OPENCODE_ZEN_API_KEY",
+        "OPENCODE_GO_API_KEY",
+        "OPENCODE_API_KEY",
+        "MINIMAX_API_KEY",
+        "MINIMAX_CN_API_KEY",
+        "XAI_API_KEY",
+        "MISTRAL_API_KEY",
+        "AWS_ACCESS_KEY_ID",
+        "AWS_SECRET_ACCESS_KEY",
+        "LM_API_KEY",
+        "LM_BASE_URL",
+    ):
+        monkeypatch.delenv(key, raising=False)
+
+
+def _run_available_models_with_cfg(monkeypatch, tmp_path, cfg):
+    old_cfg = dict(config.cfg)
+    old_mtime = config._cfg_mtime
+    old_models_cache_path = config._models_cache_path
+    old_config_path_getter = config._get_config_path
+
+    monkeypatch.setattr(config, "_models_cache_path", tmp_path / "models_cache.json")
+    monkeypatch.setattr(config, "_get_config_path", lambda: tmp_path / "missing-config.yaml")
+    monkeypatch.setattr("api.profiles.get_active_hermes_home", lambda: tmp_path, raising=False)
+    config.cfg.clear()
+    config.cfg.update(cfg)
+    config._cfg_mtime = 0.0
+    config.invalidate_models_cache()
+    try:
+        return config.get_available_models()
+    finally:
+        config.cfg.clear()
+        config.cfg.update(old_cfg)
+        config._cfg_mtime = old_mtime
+        monkeypatch.setattr(config, "_models_cache_path", old_models_cache_path)
+        monkeypatch.setattr(config, "_get_config_path", old_config_path_getter)
+        config.invalidate_models_cache()
+
+
+def _provider_groups(result):
+    return {group["provider_id"]: group for group in result["groups"]}
+
+
+def test_anthropic_token_env_var_surfaces_anthropic_models(monkeypatch, tmp_path):
+    """ANTHROPIC_TOKEN should detect the Anthropic provider through fallback."""
+    _clear_provider_env(monkeypatch)
+    _force_env_fallback(monkeypatch)
+    monkeypatch.setenv("ANTHROPIC_TOKEN", "token-only-value")
+
+    result = _run_available_models_with_cfg(monkeypatch, tmp_path, {"model": {}})
+    groups = _provider_groups(result)
+    assert "anthropic" in groups, (
+        "ANTHROPIC_TOKEN should surface the Anthropic picker provider when the "
+        "hermes_cli path is unavailable."
+    )
+    assert groups["anthropic"]["provider"] == "Anthropic"
+    assert groups["anthropic"]["models"], "Anthropic fallback should include model entries"
+
+
+def test_whitespace_only_anthropic_oauth_env_vars_do_not_surface_anthropic(monkeypatch, tmp_path):
+    """A whitespace-only ANTHROPIC_TOKEN / CLAUDE_CODE_OAUTH_TOKEN must NOT
+    false-positive the Anthropic provider (env values are stripped before the
+    availability check)."""
+    for ws_var in ("ANTHROPIC_TOKEN", "CLAUDE_CODE_OAUTH_TOKEN"):
+        _clear_provider_env(monkeypatch)
+        _force_env_fallback(monkeypatch)
+        monkeypatch.setenv(ws_var, "   \t  ")
+
+        result = _run_available_models_with_cfg(monkeypatch, tmp_path, {"model": {}})
+        groups = _provider_groups(result)
+        assert "anthropic" not in groups, (
+            f"a whitespace-only {ws_var} must not surface the Anthropic provider"
+        )
+
+
+def test_claude_code_oauth_token_env_var_surfaces_anthropic_models(monkeypatch, tmp_path):
+    """CLAUDE_CODE_OAUTH_TOKEN should detect the Anthropic provider through fallback."""
+    _clear_provider_env(monkeypatch)
+    _force_env_fallback(monkeypatch)
+    monkeypatch.setenv("CLAUDE_CODE_OAUTH_TOKEN", "oauth-token-only-value")
+
+    result = _run_available_models_with_cfg(monkeypatch, tmp_path, {"model": {}})
+    groups = _provider_groups(result)
+    assert "anthropic" in groups, (
+        "CLAUDE_CODE_OAUTH_TOKEN should surface the Anthropic picker provider when "
+        "the hermes_cli path is unavailable."
+    )
+    assert groups["anthropic"]["provider"] == "Anthropic"
+    assert groups["anthropic"]["models"], "Anthropic fallback should include model entries"