agentcore-harness-builder

# AWS Bedrock AgentCore Harness Builder ## Overview A **Harness** is AWS Bedrock AgentCore's declarative, fully-managed way to run an agent. You hand AWS a JSON configuration — model, system prompt, tools, memory, skills, limits — and AWS runs the agent loop (Strands under the hood) inside a per-session Firecracker microVM with its own filesystem and shell. No container to build, no agent loop to write. You change behavior by changing config, not redeploying code, and you can override model/prompt per invocation. This skill builds a **complete, best-practice Harness use case** that exercises every AgentCore capability the user needs, wired correctly the first time. Harness is **generally available** (~16 regions; only Payments remains preview), but it is still fast-moving and the real API shapes often differ from the published docs — this skill encodes the hard-won facts so you don't rediscover them through validation errors. ### The two-plane mental model (internalize this first) AgentCore has two distinct API surfaces. Confusing them is the #1 source of wasted time. | Plane | What it is | How you call it | |---|---|---| | **Control plane** | Create/configure/inspect resources (harness, memory, runtimes) | `boto3.client("bedrock-agentcore-control")` — `create_harness`, `update_harness`, `create_memory`, … | | **Data plane** | Invoke a running harness | `boto3.client("bedrock-agentcore")` — `invoke_harness` | The agent-side SDK (`pip install bedrock-agentcore`) is a *t...