nemo-relay-instrument-typed-wrappers

# Use Typed Wrappers And Codecs Use this skill when an application wants stronger domain types than raw JSON for tool or LLM integration. Keep typed boundaries explicit so middleware still sees predictable JSON. ## Default Guidance - Prefer plain JSON first for initial adoption. - Reach for typed wrappers when the application already has stable domain models. - Keep in mind that middleware still operates on JSON, not typed objects. ## Embedded Codec Model - A typed value codec is a pure boundary translator. It converts application-facing values to JSON before NeMo Relay emits events or runs middleware, then converts JSON back into the framework callback or caller type. - Python exposes `JsonPassthrough`, `DataclassCodec`, `PydanticCodec`, and `BestEffortAnyCodec`. Node.js exposes `JsonPassthrough` plus custom `Codec<T>` implementations. - Use `BestEffortAnyCodec` only at boundaries where strict schemas are not available. Prefer dataclass, Pydantic, or explicit Node.js codecs when the framework owns a stable schema. - Provider codecs are different from typed value codecs: they normalize provider-specific LLM requests and responses so middleware and subscribers can inspect messages, tools, model names, generation parameters, and response annotations. - Built-in provider codecs include `OpenAIChatCodec`, `OpenAIResponsesCodec`, and `AnthropicMessagesCodec` in Python, Node.js, and Rust. Choose the codec that matches the actual provider payload shape. - ...