What an agentic harness is
An agentic harness is the runtime around Claude: allowed tools, memory, max steps, approvals, logging, and evals. The model reasons. The harness decides what it is allowed to do. InferentCloud ships harnesses so operators get completed work, not a chat window with no policy.
Tools before prompts
Name tools for real business actions: create ticket, update CRM, fetch order, search docs. Keep descriptions strict. Validate arguments before side effects. If a tool can spend money or change customer records, put a human gate in the harness, not in a later Slack thread.
Evals and regression
Every production harness needs a golden set: messy emails, empty CRM fields, angry tickets. Score faithfulness, task success, and unsafe tool calls when prompts or tools change. Without evals, a “small prompt tweak” is a silent product change.
Observability
Log traces: user intent, tool names, latency, and cost. Operators should inspect a run the same way they inspect a failed job. That is how agency delivery stays accountable.
Key takeaway
Claude is the reasoning core. The harness is the product. Design tools, evals, and guardrails first, then the UI.
