Instrument Tool And LLM Calls

Instrument Tool And LLM Calls

Use this skill when an app already has tool functions or model/provider calls and needs to run them through NeMo Relay correctly. Keep the original callable behavior stable while adding Relay lifecycle capture.

Default Guidance

• Put a scope around the natural agent, request, workflow, or graph boundary.
• Use managed execution APIs first:
  • Rust: tool_call_execute(ToolCallExecuteParams::builder()...), llm_call_execute(LlmCallExecuteParams::builder()...)
  • Python: tools.execute(...), llm.execute(...)
  • Node.js: toolCallExecute(...), llmCallExecute(...)
  • Go: tools.Execute(...), llm.Execute(...) or the top-level wrappers
• Use manual lifecycle APIs only when the host framework cannot be wrapped by the managed execute helpers.

Embedded Runtime Semantics

• Managed tool and LLM execution runs conditional-execution guardrails first on the raw input. If rejected, the runtime emits a standalone mark event and does not run request intercepts or the callable.
• Request intercepts run after conditional guardrails and rewrite the real input that reaches execution intercepts and the callback.
• Sanitize-request guardrails affect emitted start-event payloads only. They do not rewrite the caller-visible request or arguments.
• Execution intercepts wrap the callback with the middleware next pattern and may short-circuit by returning their own result.
• Sanitize-response guardrails affect emitted end-event payloads only. The value returned to application code remains the raw callback or execution-intercept result.
• If execution fails after the start event has been emitted, the runtime still emits an end event without a semantic output payload.
• Tool calls are named operations with JSON-compatible arguments and results. Keep the original tool callable responsible for business logic; let NeMo Relay own lifecycle events, middleware, and metadata.
• LLM calls use an LLMRequest made of metadata plus content. Pass model names and stable call identifiers when they matter for trace export or diagnostics.
• Manual lifecycle APIs are for framework adapters that already own execution.