Prism is a small, compositional metalanguage for specifying the behaviour of tool-using software agents. Rather than introducing ad hoc control constructs, Prism is built around a fixed core context, Core1, which provides a minimal background grammar of categories numbers, strings, user prompts, tools together with abstract combinators for booleans, predicates, pairs, and lists. Agent policies are written as ordinary expressions using a single abstraction operator so that conditionals appear as selections between alternatives instead of imperative if-else blocks. Domains extend the core by defining their own context-mini-grammars that introduce new categories, predicates, and external tools while reusing the same compositional machinery. We illustrate this with worked examples from thermostat control, home security, e-commerce recommendation, and medical monitoring, showing how natural language decision rules can be mapped to inspectable, executable policies. From a linguistic perspective, Prism enforces a clear separation between a reusable grammar-like core and domain specific lexicons and treats tools as bridges between internal policy representations and the external world. From an engineering perspective, it offers a compact interface language for agent control, making the space of possible actions explicit and amenable to analysis, verification, and safety constraints.

翻译：Prism是一种用于指定工具使用软件智能体行为的小型组合元语言。它并非引入临时控制结构，而是围绕一个固定的核心上下文Core1构建，该核心提供了由数字、字符串、用户提示、工具等类别构成的最小化背景语法，并包含布尔值、谓词、对偶和列表的抽象组合子。智能体策略通过单一抽象算子以普通表达式形式编写，使得条件判断呈现为备选方案间的选择，而非命令式的if-else块。领域通过定义自身的上下文微型语法来扩展核心，引入新类别、谓词和外部工具，同时复用相同的组合机制。我们通过恒温器控制、家庭安防、电子商务推荐和医疗监测等实例进行演示，说明如何将自然语言决策规则映射为可检查、可执行的策略。从语言学视角看，Prism强制实现了可复用类语法核心与领域特定词汇间的清晰分离，并将工具视为内部策略表示与外部世界间的桥梁。从工程学视角看，它提供了一种紧凑的智能体控制接口语言，使可能动作空间显式化，便于分析、验证及安全约束的施加。