Build, debug, and publish pi (the agent harness from earendil-works, @earendil-works/pi-coding-agent) extensions — the default-export factory, lifecycle event hooks, custom tools, slash commands, shortcuts, CLI flags, custom model/OAuth providers, and full TUI. Use when working in a pi extension repo or anytime the task touches @earendil-works/pi-coding-agent, a `.pi/` or `~/.pi/agent/` extensions dir, or `pi -e`. Use when: "block rm -rf before it runs" (tool_call → {block}), "add a tool the model can call" (registerTool + typebox), "confirm before a destructive command" (ctx.ui.confirm), "add a /command" (registerCommand), "inject context on every prompt" (before_agent_start), "register a custom model provider / proxy / OAuth login" (registerProvider), "persist a todo list across restarts" (appendEntry + reconstruct), "spawn a subagent" (subprocess tool), "draw a status line / widget / footer" (ctx.ui), "my extension's hook never fires", or "publish my extension as a pi package". Covers the `~/.pi/agent/exte
Build, debug, and publish opencode plugins with the @opencode-ai/plugin SDK — hooks, custom tools, auth/model providers, and event handling. Use when working in an opencode plugin repo or anytime the task touches @opencode-ai/plugin or @opencode-ai/sdk. Use when: "create a plugin to block dangerous bash commands" (tool.execute.before), "add a custom tool the agent can call" (tool() helper), "show a toast on file edit" (event hook + tui), "build a custom auth/OAuth provider" (auth hook), "inject context on the first message of a session" (chat.message), "override temperature for the build agent" (chat.params), "run code when a session finishes" (session.idle event), "my plugin loads but the hook never fires", "console.log breaks the TUI", or "publish my plugin to npm". Covers the plural .opencode/plugins/ layout and opencode.json plugin array.