Julia package development

Work on a warm Julia session and verify each edit as you make it. The cost of a fresh process is time-to-first-execution paid once per session, so keep one alive and check every change against it. An agent that verifies per step writes better Julia: genuinely non-allocating where asked, and more likely to get the task right first time.

Warm session

Start one session and reuse it. Under Claude Code the AgentREPL.jl plugin gives a warm MCP session over STDIO, with no open port. Its eval tool is synchronous, so a call returns when evaluation finishes. A PostToolUse hook nudges you to reload after editing a .jl file.