01 / What each boundary answers
Compare the decision, not the label.
Permit MCP Gateway documents real-time authorization at call_tool, identifying the agent and checking tool access before proxying upstream.
Trace originating grant, task-specific argument scope, downstream enforcement and observed effect beyond the MCP call.
02 / Same operating case
Which request must be stopped?
A support agent can call update_customer but supplies an account ID from another tenant.
Evaluation exercise
Use Permit MCP Gateway’s call_tool path for a permitted tool with a forbidden account argument. Then try a direct upstream request; record which policy layer sees and rejects each call.
03 / Architecture fit
How the controls can compose
Gateway authorization and an executor-side task decision may be complementary depending on the actual deployment.
Do not infer that Permit.io cannot enforce arguments through other configurations; assess the documented gateway mode and deployed policy.
04 / Evidence
Prove the decision and the effect separately.
Compare gateway allow/deny record, argument digest, downstream API decision and customer state.
Primary sources