diff --git a/tests/code_coverage_tests/test_provider_cache.py b/tests/code_coverage_tests/test_provider_cache.py
index ac1ccd5692b..c24ba8d6221 100644
--- a/tests/code_coverage_tests/test_provider_cache.py
+++ b/tests/code_coverage_tests/test_provider_cache.py
@@ -33,7 +33,13 @@ from provider_cache import (
     successful_response,
 )
 from provider_cache_redis import PUBLISH, RedisCommands, RedisResponseStore, configured_cache, redis_store
-from provider_cache_routing import LIVE_PROVIDER_REQUIRED, route_cache_model
+from provider_cache_routing import (
+    BEDROCK_CROSS_REGION_PREFIX,
+    BEDROCK_EDGE_MODELS,
+    LIVE_PROVIDER_REQUIRED,
+    bedrock_region,
+    route_cache_model,
+)
 from fixture_mode import SESSION_TEST_KEY
 from provider_edge import EDGE_MOUNTS, configured_cache_backend, resolve_mount, start_provider_edge
 from provider_edge_bedrock import bedrock_signer
@@ -856,6 +862,31 @@ def test_bedrock_deployments_the_edge_must_not_touch_keep_their_direct_route(par
     assert routed is params
 
 
+@pytest.mark.parametrize("declared,expected", [
+    (None, "us-east-1"),
+    ("us-west-2", "us-west-2"),
+    ("eu-west-1", "eu-west-1"),
+    ("os.environ/AWS_REGION", "us-east-1"),
+    ("os.environ/ANY_OTHER_NAME", "us-east-1"),
+])
+def test_a_region_only_the_proxy_can_resolve_falls_back_to_the_default_mount(
+    declared: str | None, expected: str,
+) -> None:
+    """A declared literal region is the one the deployment meant. A region the
+    proxy resolves from its own environment is one the run pod cannot see, and
+    the default mount answers it."""
+    assert bedrock_region(declared) == expected
+
+
+def test_every_model_on_the_edge_allowlist_is_a_cross_region_profile() -> None:
+    """Answering an env-referenced region with the default mount is only correct
+    for a profile that fans out across the US regions and is reachable from any
+    of them. A single-region model on this list would be sent to a region it may
+    not exist in, so the list is where that is caught."""
+    assert BEDROCK_EDGE_MODELS
+    assert all(model.startswith(BEDROCK_CROSS_REGION_PREFIX) for model in BEDROCK_EDGE_MODELS)
+
+
 @pytest.mark.parametrize("mode", ["batch", "realtime", "image_generation"])
 def test_a_bedrock_deployment_with_a_mode_keeps_its_direct_route(mode: ModelMode) -> None:
     params: Final = LiteLLMParamsBody(model="bedrock/us.anthropic.claude-haiku-4-5-20251001-v1:0")
diff --git a/tests/e2e/provider_cache_routing.py b/tests/e2e/provider_cache_routing.py
index 97e05344423..f9775a2b152 100644
--- a/tests/e2e/provider_cache_routing.py
+++ b/tests/e2e/provider_cache_routing.py
@@ -21,22 +21,18 @@ BEDROCK_EDGE_MODELS: Final = frozenset(
 ENV_REFERENCE_PREFIX: Final = "os.environ/"
 
 
-def bedrock_region(declared: str | None, model: str) -> str | None:
-    """The region whose edge mount a deployment belongs to, or None when the
-    harness cannot know it.
+def bedrock_region(declared: str | None) -> str:
+    """The region whose edge mount a deployment belongs to.
 
-    Most Bedrock deployments declare `os.environ/AWS_REGION`, which the proxy
-    resolves from its own environment. The run pod does not share that
-    environment, so the harness genuinely does not know the region. A `us.`
-    inference profile fans out across the US regions and is reachable from any
-    of them, so the default entry point is correct for those whatever the proxy
-    resolved; anything else keeps its direct path rather than being sent to a
-    region the model may not exist in."""
-    if declared is None:
+    Most Bedrock deployments declare `os.environ/AWS_REGION`, which only the
+    proxy can resolve from its own environment; the run pod does not share it.
+    Answering those with the default mount is correct because every model on the
+    edge allowlist is a `us.` inference profile, which fans out across the US
+    regions and is reachable from any of them. That invariant is enforced on the
+    allowlist itself rather than re-checked per call."""
+    if declared is None or declared.startswith(ENV_REFERENCE_PREFIX):
         return DEFAULT_BEDROCK_REGION
-    if not declared.startswith(ENV_REFERENCE_PREFIX):
-        return declared
-    return DEFAULT_BEDROCK_REGION if model.startswith(BEDROCK_CROSS_REGION_PREFIX) else None
+    return declared
 
 
 def bedrock_mount(params: LiteLLMParamsBody) -> str | None:
@@ -51,8 +47,7 @@ def bedrock_mount(params: LiteLLMParamsBody) -> str | None:
     model: Final = route.partition("/")[2] or route
     if model not in BEDROCK_EDGE_MODELS:
         return None
-    region: Final = bedrock_region(params.aws_region_name, model)
-    return None if region is None else f"bedrock/{region}"
+    return f"bedrock/{bedrock_region(params.aws_region_name)}"
 
 
 def route_bedrock(