MCP standardizes how tools and context are exposed to models, but reliable agent systems still depend on orchestration, policy, durability, observability, and approval-driven runtime design.
A practical reference blueprint for an agent harness, grounded in the live harness-engineering repo and updated with a real blueprint export instead of an imaginary architecture diagram.
Why agent performance engineering lives in the harness, with a real repo update that adds per-step timing and workload estimates to trace summaries and run summaries.
A practical look at what security actually means in an agent harness after adding a checked-in policy config, provider env handling, and verification surfaces to the live demo repo.
A practical look at small multi-agent systems after adding explicit planner→executor→reviewer handoffs to the live harness-engineering demo.
A practical look at harness-level sandboxing and isolation after adding explicit action categories, policy checks, and write-path enforcement to the live harness-engineering demo.
A practical look at tracing, operator-facing observability, and trace-aware evals in the live harness-engineering demo after adding persisted trace summaries and lightweight eval fixtures.
A practical look at human-in-the-loop design in the live harness-engineering demo: approval as explicit workflow state, not a chat courtesy, plus a new pending-action inspection surface for operators.
A practical look at memory architecture in the live harness-engineering demo: separating working context, durable session state, and retrieval memory instead of calling everything memory.
Checkpointing, approval-safe pause/resume, and replay-friendly run history are what turn an agent demo into an operational system. A practical look at the live harness-engineering repo after adding persisted run …
