Nexa

Write, compile, run, test, and debug Nexa programs. Nexa is the first Harness Native Agent Language — compile .nx scripts to Python via `nexa build`, then execute with full autonomous agent capabilities including tool calling, semantic control flow, and Harness Native Runtime (E,T,C,S,L,V). Use this skill when asked to create or modify .nx files, install Nexa, run `nexa build` or `nexa run`, declare agents/tools/flows, write @tool functions, use autoloop/with_context/ snapshot/verify/reflect primitives, or build any AI agent application with Nexa syntax — even if the user doesn't mention Nexa by name but describes "building an AI agent with a DSL that compiles to Python." Also covers v2.2.1 Context-as-Structure (context { } block), v2.3.1 Terminal UI (std.ui DSL), and @tool edit_file for diff-style edits.