Originally published on fakecloud.dev . Bedrock Guardrails are one of the better pieces of AWS infrastructure in the last year. You define a policy — filter out hate, block PII leakage, deny certain topics, enforce contextual grounding on RAG outputs — and either apply it to an entire model invocation via guardrailIdentifier , or call ApplyGuardrail directly on arbitrary text. Useful, sharp, limited-in-scope. The problem is testing. A serious guardrail config is an iterative thing — you tune filter strengths, add denied topics, tweak word filters, and test each change. Each test-cycle turn against real AWS costs tokens and time. And if the thing you're trying to guard against is LLM output, you're paying for the model call and the guardrail evaluation. fakecloud runs the full Bedrock Guardrails surface locally. CreateGuardrail , versioning, UpdateGuardrail , DeleteGuardrail , ApplyGuardrail , ListGuardrails — the whole thing. More interestingly, the data plane actually evaluates content. PII detection works.…