diff --git a/api/config.py b/api/config.py
index 34c28173..a67d5139 100644
--- a/api/config.py
+++ b/api/config.py
@@ -3246,7 +3246,9 @@ def _filter_reasoning_efforts_for_provider(
     normalized = list(dict.fromkeys(normalized))
     provider = _resolve_provider_alias(str(provider_id or "").strip().lower())
     bare = _strip_provider_hint_for_reasoning(model_id).lower().rsplit("/", 1)[-1]
-    if provider == "openai-codex":
+    # OpenAI-family lanes (Codex, direct OpenAI, Azure Foundry) cap GPT-5 at xhigh
+    # and o-series at high — 'max' is a WebUI-only level none of them accept.
+    if provider in {"openai-codex", "openai", "openai-api", "azure-foundry", "azure-openai", "azure"}:
         if bare.startswith(("o1", "o3", "o4")):
             return [eff for eff in normalized if eff in {"low", "medium", "high"}]
         if bare.startswith("gpt-5"):
@@ -3258,7 +3260,14 @@ def _filter_reasoning_efforts_for_provider(
     # Dropping 'max' here lets the existing downgrade ladder land on xhigh/high.
     if provider in {"gemini", "google", "google-gemini", "google-vertex", "vertex"}:
         return [eff for eff in normalized if eff != "max"]
-    if provider in {"anthropic", "claude", "anthropic-claude"} and _is_pre_adaptive_anthropic(bare):
+    # Legacy Claude is pre-adaptive whether served natively OR via Azure Foundry /
+    # Bedrock / Vertex — the ceiling follows the MODEL, not just the provider name.
+    _anthropic_lanes = {
+        "anthropic", "claude", "anthropic-claude",
+        "azure-foundry", "azure-openai", "azure", "bedrock", "aws-bedrock",
+        "vertex", "google-vertex",
+    }
+    if provider in _anthropic_lanes and "claude" in bare and _is_pre_adaptive_anthropic(bare):
         return [eff for eff in normalized if eff != "max"]
     return normalized
 
diff --git a/tests/test_reasoning_effort_model_capabilities.py b/tests/test_reasoning_effort_model_capabilities.py
index 4c438485..4a13b903 100644
--- a/tests/test_reasoning_effort_model_capabilities.py
+++ b/tests/test_reasoning_effort_model_capabilities.py
@@ -362,3 +362,28 @@ def test_max_effort_preserved_for_adaptive_anthropic_and_deepseek():
     assert cfg.coerce_reasoning_effort_for_model(
         "max", model_id="deepseek-reasoner", provider_id="deepseek"
     ) == "max"
+
+
+def test_max_degrades_across_all_openai_family_lanes():
+    # 'max' is WebUI-only; direct OpenAI, openai-api, and Azure Foundry GPT-5 all
+    # cap at xhigh (o-series at high), not just openai-codex. (#4627 re-gate)
+    for prov in ("openai", "openai-api", "azure-foundry", "openai-codex"):
+        assert cfg.coerce_reasoning_effort_for_model(
+            "max", model_id="gpt-5.1", provider_id=prov
+        ) == "xhigh", f"gpt-5 on {prov} must degrade max->xhigh"
+        assert cfg.coerce_reasoning_effort_for_model(
+            "max", model_id="o3", provider_id=prov
+        ) == "high", f"o-series on {prov} must degrade max->high"
+
+
+def test_max_degrades_for_azure_bedrock_hosted_legacy_claude():
+    # Legacy Claude via Azure Foundry / Bedrock is still pre-adaptive; the ceiling
+    # follows the model, not just the provider name. (#4627 re-gate)
+    for prov in ("azure-foundry", "bedrock"):
+        assert cfg.coerce_reasoning_effort_for_model(
+            "max", model_id="claude-sonnet-4-20250514", provider_id=prov
+        ) == "xhigh", f"legacy Claude on {prov} must degrade max->xhigh"
+    # adaptive Claude via azure preserves max
+    assert cfg.coerce_reasoning_effort_for_model(
+        "max", model_id="claude-opus-4.6", provider_id="azure-foundry"
+    ) == "max"