diff --git a/agentex/openapi.yaml b/agentex/openapi.yaml
index b122020e..100fb9b8 100644
--- a/agentex/openapi.yaml
+++ b/agentex/openapi.yaml
@@ -5221,6 +5221,12 @@ components:
         acp_type:
           $ref: '#/components/schemas/ACPType'
           description: The type of ACP to use for the agent.
+        principal_context:
+          anyOf:
+          - {}
+          - type: 'null'
+          title: Principal Context
+          description: Principal used for authorization
         registration_metadata:
           anyOf:
           - additionalProperties: true
diff --git a/agentex/src/api/routes/agents.py b/agentex/src/api/routes/agents.py
index 245c865e..b7d370d3 100644
--- a/agentex/src/api/routes/agents.py
+++ b/agentex/src/api/routes/agents.py
@@ -195,11 +195,15 @@ async def register_agent(
     If agent_id is not provided, the system will look for an existing agent by name and update it,
     or create a new one if it doesn't exist.
     """
-    enforce_ownership = _has_resolvable_creator(authorization_service.principal_context)
+    principal_context = authorization_service.principal_context
+    if not _has_resolvable_creator(principal_context):
+        principal_context = request.principal_context
+    enforce_ownership = _has_resolvable_creator(principal_context)
     if enforce_ownership:
         await authorization_service.check(
             AgentexResource.agent("*"),
             AuthorizedOperationType.create,
+            principal_context=principal_context,
         )
     logger.info(
         "Registering agent name=%s agent_id=%s acp_type=%s",
@@ -220,6 +224,7 @@ async def register_agent(
         if enforce_ownership:
             await authorization_service.grant(
                 AgentexResource.agent(agent_entity.id),
+                principal_context=principal_context,
             )
         response_fields = agent_entity.model_dump()
         existing_key = await api_keys_use_case.get_internal_api_key_by_agent_id(
diff --git a/agentex/src/api/schemas/agents.py b/agentex/src/api/schemas/agents.py
index 40fd4273..79d92532 100644
--- a/agentex/src/api/schemas/agents.py
+++ b/agentex/src/api/schemas/agents.py
@@ -88,6 +88,9 @@ class RegisterAgentRequest(BaseModel):
         description="Optional agent ID if the agent already exists and needs to be updated.",
     )
     acp_type: ACPType = Field(..., description="The type of ACP to use for the agent.")
+    principal_context: Any | None = Field(
+        default=None, description="Principal used for authorization"
+    )
     registration_metadata: dict[str, Any] | None = Field(
         default=None,
         description="The metadata for the agent's registration.",
diff --git a/agentex/tests/unit/api/test_agents_authz.py b/agentex/tests/unit/api/test_agents_authz.py
index 650df233..581d79d5 100644
--- a/agentex/tests/unit/api/test_agents_authz.py
+++ b/agentex/tests/unit/api/test_agents_authz.py
@@ -392,12 +392,13 @@ def _mocks(principal_context):
         return authorization, agents_use_case, api_keys_use_case
 
     @staticmethod
-    def _request():
+    def _request(principal_context=None):
         return RegisterAgentRequest(
             name="my-agent",
             description="d",
             acp_url="http://agent:5000",
             acp_type=ACPType.ASYNC,
+            principal_context=principal_context,
         )
 
     @pytest.mark.parametrize("principal_context", [None, {}, {"account_id": "acct"}])
@@ -413,6 +414,21 @@ async def test_unresolvable_creator_skips_check_and_grant(self, principal_contex
         use_case.register_agent.assert_awaited_once()
         assert resp.agent_api_key == "internal-key"
 
+    async def test_body_principal_enforces_check_and_grant(self):
+        # Legacy deployed pods send the deploy principal in the body because
+        # /agents/register is whitelisted and has no request-state principal.
+        body_principal = {"user_id": "u", "account_id": "acct"}
+        authz, use_case, api_keys = self._mocks(principal_context=None)
+
+        await register_agent(
+            self._request(principal_context=body_principal), use_case, authz, api_keys
+        )
+
+        authz.check.assert_awaited_once()
+        assert authz.check.await_args.kwargs["principal_context"] == body_principal
+        authz.grant.assert_awaited_once()
+        assert authz.grant.await_args.kwargs["principal_context"] == body_principal
+
     async def test_dict_principal_enforces_check_and_grant(self):
         authz, use_case, api_keys = self._mocks(
             principal_context={"user_id": "u", "account_id": "acct"}