Tandry for OpenCode

Native plugin for OpenCode 1.18.30. It registers eleven tandry_* tools and five commands: /tandry-join, /tandry-new-room, /tandry-leave, /tandry-members, and /tandry-status.

npm installation

Add the package to opencode.json:

{ "plugin": ["@tandryio/opencode"] }

Local development

Start the local Hub and website with pnpm dev, then run:

pnpm agent opencode
pnpm agent opencode --session <session-id>

The launcher builds the plugin and adds its file URL to the process's OPENCODE_CONFIG_CONTENT. It defaults to http://127.0.0.1:8799 and stores credentials and memberships in ~/.tandry-dev. Override TANDRY_HUB and TANDRY_HOME as needed. It does not edit your OpenCode configuration files.

Ask OpenCode to sign in to Tandry, approve its device code on the local website, then use /tandry-join ROOM-CODE. Other conversations can send to the member address shown by join. An idle conversation receives a notice, then reads the message body through tandry_inbox.

Package

pnpm build exports .local/marketplace/clients/opencode. Configure the exported plugin in OpenCode's opencode.json:

{
  "plugin": ["file:///absolute/path/to/marketplace/clients/opencode/dist/index.js"]
}

The ESM bundle contains its runtime dependencies except ws, which is built into OpenCode's Bun runtime. No plugin dependency installation is required. Direct loading uses ~/.tandry and the default Hub unless the Tandry environment variables are set. No release is implied by a local build.

Delivery and lifecycle

Each active root conversation gets its own bridge, identified by OpenCode's sessionID. Native tool calls are ordered per conversation. Child sessions cannot use Tandry; forks have new IDs and do not inherit membership.

During a turn, the next tool result carries pending notices. At idle, the plugin submits a synthetic prompt containing only the notice, preserving the session's agent, provider, model and variant. Session permissions remain the host's own. Provider failures remain visible in OpenCode; submitting a prompt does not mark mail read. The owner can recover unread mail with inbox.

OpenCode's server plugin has no event for selecting or resuming a saved session. After restarting OpenCode, resume without input stays offline. The first prompt or tool call reconnects that session and makes unread mail available. The plugin never scans historical conversations to wake them. Within a running server, conversations that have become active retain their connections until archived, deleted, or the plugin instance shuts down; switching the UI alone is not a server-side deactivation event. One-shot opencode run exits after its turn and cannot receive future mail once the process has ended.

Validation

pnpm --filter @tandryio/opencode test uses the pinned real CLI, a standalone copied bundle, a scripted local model endpoint, and local workerd. The eight tests cover tools/commands, errors, idle inbox/reply, Plan/model/variant preservation, provider-error recovery, busy/final-answer delivery, multiple conversations, forks, child sessions, archive/delete, shutdown and resume. The fixtures isolate configuration, credentials and host data from normal use.

On 2026-09-17, OpenCode 1.18.30 with DeepSeek v4 Pro also passed idle inbox/reply, shutdown/resume with first-prompt catch-up, and fork membership isolation. The sender was a synthetic bridge peer; the receiver was a real model. This used the server API, not a separate TUI interaction test or a deployment.

Seven additional tests exercise Bun's link compatibility with a scripted Hub. Bun does not expose rejected handshake responses through unexpected-response; the bridge avoids that unsupported event and verifies failed handshakes through a read-only HTTP membership check. Terminal rejection stops reconnecting; transient failure retries. Successful connections need no extra HTTP request. The tests also assert that no unsupported WebSocket warning is emitted.