Runtime Boundary

Runlet is a runtime library, not an application platform.

What belongs in the runtime

The runtime should own:

• the execution loop
• context preparation before model calls
• tool execution inside the loop
• hook invocation
• structured event emission
• run policies and stop conditions

What should stay outside

The runtime should not own:

• product-specific session logic
• durable user memory policy
• retrieval pipelines
• HTTP APIs
• background job orchestration
• multi-tenant control planes

Practical rule

If a behavior is application-specific and different teams would reasonably want to implement it differently, it should usually live outside Runtime.

That is why Runlet exposes low-level state primitives and request entrypoints instead of a built-in conversation memory system.