Custom agents in Markdown now support YAML frontmatter and H1-delimited system prompts, with fields for agent type, subagent inheritance, visibility, and command execution policy. The /copy command accepts an optional index argument, and /codesearch streams results progressively. Dynamically defined subagents automatically write in Markdown format for external builds. Default read access to the system temporary directory is now available, alongside stability fixes for the terminal UI, artifact viewer, and sandbox.