OpenCode

Install

nah hook opencode install

OpenCode installation is not supported on Windows. Install and uninstall return runtime-platform-unsupported before writing, and status reports not configured.

To deny explicit evaluation failures and bounded analysis refusals, install with --fail-closed. Ordinary unknown or opaque calls still delegate. --fail-open restores the default; flagless reinstall preserves a recognized mode. The guarantee requires the loaded nah process to return a response; missing hooks/binaries, runtime timeout, process termination, bypass, and broken output pipes remain outside it.

Restart OpenCode. Remove only nah's plugin with:

nah hook opencode uninstall

The installer writes one dependency-free ESM plugin at ~/.config/opencode/plugins/nah.js. OpenCode 2.x loads it as plugin ID nah, and its execute.before tool hook invokes nah without a shell.

nah hook opencode status checks only this file, not whether OpenCode loaded it. opencode plugin list --builtin lists nah once loaded (it starts OpenCode's background service); load errors log failed to load plugin.

Nah supports OpenCode 2.x only; 2.0.18 was live-verified on 2026-09-27. OpenCode 1.x rejects the plugin, so 1.x sessions run without nah even though status reports current wiring. Upgrade to 2.x (@opencode/cli, which installs opencode and opencode2), then reinstall; an older nah plugin reports reinstall required.

Behavior

Shell, read, write, edit, patch, glob, and grep calls use the shared policy. A shell call's workdir is resolved against its session directory. A glob with hidden: true is analyzed but reported incomplete, because nah treats a leading * as skipping hidden entries; --fail-closed therefore blocks it. Other built-in, MCP, and custom tools remain opaque to nah and delegate. Blocks throw a nah-branded error before OpenCode's permission check. Every other call delegates to OpenCode's native allow/ask/deny flow. --auto and the TUI's auto-approve mode automatically approve calls that would otherwise ask, but do not disable plugins or explicit deny rules. Delegated calls can therefore execute without another prompt in auto mode.

Boundaries

OpenCode loads global plugins when its server starts and reloads them when watched plugin files change. Config files that disable the nah plugin ID (a "-nah" or "-*" entry in a project opencode.json(c) or an OPENCODE_CONFIG file), servers started without the plugin (including remote servers), plugin load failures, and trusted plugins that act directly remain outside nah. OpenCode runs hook handlers sequentially; later plugins see and can mutate a call after nah delegates it. Plugin hook errors abort the tool, but the nah plugin catches adapter failure in the default mode and delegates without notice: OpenCode 2.x gives server plugins no notification API.

A nonstandard XDG_CONFIG_HOME is rejected because the installer owns only the standard plugin path. Other plugin lifecycle and configuration remain runtime-owned.

While active, this adapter blocks visible lifecycle commands and direct mutations to its nah-owned plugin. Visible opencode and opencode2 launches, including npx/bunx/bun x @opencode/cli, with an alternate XDG_CONFIG_HOME or OPENCODE_CONFIG_DIR, or with OPENCODE_CONFIG_CONTENT that mentions plugins or contains a \u escape, also block. Other runtime configuration remains user-owned. The agent is told not to retry protected changes; an operator can use nah nap from another terminal.

This integration is best effort: runtime APIs and hook behavior can change. After upgrades, verify the latest official upstream documentation linked below, inspect the loaded hook, and test it before relying on nah. See OpenCode's plugin documentation, permission documentation, and the V1 plugin migration guide.