nemo-relay-instrument-context-isolation

# Use Context Isolation Use this skill when an application runs concurrent requests, worker pools, async tasks, goroutines, or multiple agents in the same process. Treat scope-stack ownership as part of the request boundary. ## Core Rule Each independent request, agent, or workflow needs its own scope stack. Do not share one mutable stack across unrelated concurrent work unless you want shared ancestry and shared scope-local middleware. ## Embedded Scope Model - A root scope is always present, and pushed scopes form a parent-child tree beneath it. - Scope hierarchy determines event parentage, lifetime boundaries, and visibility for scope-local middleware and subscribers. - Standard scope types include `Agent`, `Function`, `Tool`, `Llm`, `Retriever`, `Embedder`, `Reranker`, `Guardrail`, `Evaluator`, `Custom`, and `Unknown`. - Scope start and end events can carry semantic `input` and `output` payloads when the scope represents a request, task, or meaningful result boundary. - Scope-local registrations disappear when the owning scope closes; use them for behavior that should not outlive a request or agent run. - Mark events are useful for retries, checkpoints, interrupts, and important state transitions that are not full spans. ## Per-Language Defaults - **Python**: rely on task-local behavior via `get_scope_stack()` and `contextvars`, or explicitly propagate when work leaves the current execution context - **Rust core**: use runtime helpers such as `cre...