Trace Coverage Ratio

Trace Coverage Ratio is the share of an agent's real production actions that leave an inspectable record: every LLM call, tool invocation, retrieval step, and handoff captured as a span. Agencies typically instrument the happy path and leave the rest dark, so the ratio sits near 20 to 40 percent while the retainer is priced as if it were 100. The gap is where disputes live, because a client asking why an agent booked the wrong slot cannot be answered from logs that never existed. Raising coverage is cheap relative to the cost of one unresolved incident: Langfuse and Arize both expose hierarchical traces that turn an opaque agent run into a replayable sequence, and Confident AI adds red-team traces for adversarial paths. Treat coverage as a contractual number, reported monthly alongside spend, and the premium for production-ready AI becomes defensible rather than asserted.