MCP, and what it costs you
A tool interface is one layer.
What the interface gives you
Model Context Protocol provides a common interface for connecting AI applications to tools and resources. It helps organize integration; the surrounding architecture still determines how the system behaves.
Inspect discovery and loading
Definition overhead depends on how the application discovers tools and what it includes in a request. Inspect the actual payload rather than assuming that every available tool is always loaded.
Engineer the boundaries
Set scoped permissions, explicit tool policies, timeouts, retry budgets, and audit traces. Treat external tool responses as untrusted data and validate their shape before using them.
Measure the whole path
Follow a request through orchestration, model calls, tool execution, and evaluation. Attribute latency and spend to those stages so changes can be tested against the actual bottleneck.