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OpenCode 1 → OpenCode 2: What Actually Changed, and How to Work Differently

Research report, compiled 2026-10-05. Covers OpenCode V2 stable releases 2.0.0 (2026-09-11) through 2.0.23 (2026-10-05) versus the V1 line (1.18.x).

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How to read this document

Every claim is tagged with where it comes from, because the quality of the evidence varies a lot:

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Plugin Output in opencode: Server Commands vs TUI Commands

A technical note for developers writing opencode plugins. It describes how plugin slash-command output works, what the relevant upstream code does, and the observable effect on plugins that try to display output without invoking the model. It sticks to verifiable behavior and cites the upstream commits/PRs; it does not speculate about anyone's intent.

TL;DR

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Developer Tooling Setup

macOS 26.3.1 (Apple Silicon) workstation configuration. Everything is installed via Homebrew 5.1.0 unless noted otherwise.

Tools at a Glance

The default macOS command-line tools were designed decades ago and show their age. They produce dense, uncolored output, ignore modern conventions like .gitignore, and lack features developers now take for granted (syntax highlighting, git awareness, fuzzy search). This setup replaces them with modern alternatives — mostly written in Rust — that are faster, produce more readable output, and work the way you'd expect in a git-centric workflow. Every replacement is aliased to the original command name so muscle memory carries over.

Tool	Replaces	Why

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OpenCode Prompt Construction

This document explains how OpenCode assembles everything the LLM sees: system prompt, tool definitions, agent configuration, and instruction files. It focuses on what's dynamic and why.

All paths are relative to the repo root.

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How the System Prompt is Built

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--- policy.json 2013-05-22 04:29:47.939198317 +0000
+++ policy.json.dpkg-dist       2013-05-20 05:02:36.000000000 +0000
@@ -1,5 +1,9 @@
 {
     "admin_required": [["role:admin"], ["is_admin:1"]],
+    "owner" : [["user_id:%(user_id)s"]],
+    "admin_or_owner": [["rule:admin_required"], ["rule:owner"]],
+
+    "default": [["rule:admin_required"]],

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#!/usr/bin/python

import libvirt
import os
import sys
import time
import uuid

try:
    instance_name = sys.argv[1]