Anterior’s symbolic-reasoning separates gathering facts from executing deterministic rules. It compiles .srg rules, requests information from an LLM, database or person, and records a decision trace. The Apache 2.0 project supports Python 3.12 or later and stdio MCP. Although developed around medical policies, it also proposes uses in other rule-heavy domains. This is a pre-1.0 research tool whose API can change. Consistent execution does not guarantee correct inputs or rules, so consequential outputs still require review.