别用提示词约束 Agent，用确定性测试代替文字规则
写代码 Agent 工作流的都该看看：与其在提示词里念叨规则，不如给每个检查点配上对应测试，省 token 还更稳。
Santiago 提出观点：能用测试自动检查的内容，就不该写进给 Agent 的文字指令里。他给出对应关系：行为用单元测试和集成测试、格式用 Formatter 和 Linter、类型用静态类型检查、API 契约用 Schema 校验、回归用回归测试、安全用静态分析和安全扫描。核心逻辑是确定性测试比写在提示词里的规则更可靠，还能省下 token。
Deterministic tests > Written instructions
Anything that should be checked automatically should have a test case:
• Checking behavior → Unit and integration tests • Checking formatting → Formatters and linters • Checking types → Static type checkers • Checking API contracts → Schema validation • Checking edge cases → Targeted tests • Checking regressions → Regression tests • Checking security → Static analysis and security scans
Don't waste tokens telling an agent to follow rules you could enforce with deterministic tests.
