Instrument Existing Agent With Prefactor SDK

Instrument a working agent that was built without Prefactor.

Core principle: instrument boundaries, not business logic.

Quick Start

1. Bootstrap Prefactor credentials with skills/bootstrap-existing-agent-with-prefactor-cli/SKILL.md (prefactor setup or prefactor setup --create).
2. Inspect the project and install the matching Prefactor adapter with the project's existing package manager (bun, npm, pnpm, or yarn).
3. Identify runtime path: built-in adapter (@prefactor/langchain, @prefactor/ai, @prefactor/openclaw, @prefactor/claude) or custom @prefactor/core adapter.
4. Add one top-level run span and child spans around LLM/tool boundaries.
5. Preserve context propagation and package-prefixed span types.
6. Record error metadata and rethrow original errors.
7. Finish spans on success, error, cancel, and stream terminal paths.
8. Verify in your project's build/test/typecheck flow, then confirm traces with prefactor agent_instances list --agent_id <agent_id> and prefactor agent_instances agent_context <instance_id>.

Prerequisite