# opencode setup

Canonical OpenCode config + Phoenix bridge plugin for the localgenai
stack. `install.sh` deploys it to `~/.config/opencode/` on a Mac.

## What's wired up

- **Local model**: `framework/qwen3-coder:30b` served by Ollama on the
  Framework Desktop, reachable over Tailscale.
- **Playwright MCP** ([@playwright/mcp](https://github.com/microsoft/playwright-mcp)) —
  browser automation. The model can navigate pages, click, fill forms,
  read DOM snapshots. Closes the agentic-browsing gap.
- **SearXNG MCP** ([mcp-searxng](https://github.com/ihor-sokoliuk/mcp-searxng)) —
  web search via your self-hosted instance at <https://searxng.n0n.io>.
  No external API keys, no rate-limit roulette.
- **Phoenix bridge plugin** (`.opencode/plugin/phoenix-bridge.js`) —
  exports OpenTelemetry spans for every LLM call, tool call, and
  subagent invocation to the Phoenix container running on the Framework
  Desktop. Per-prompt waterfall / flamegraph viz at
  <http://framework:6006>.

## Setup

```sh
./install.sh
```

Idempotent — re-run after editing `opencode.json` or pulling changes to
the plugin. Each step checks before doing work. Specifically:

1. Verifies Homebrew is present (won't install it for you)
2. `brew install node uv jq sst/tap/opencode` (skips if already at latest)
3. Pre-caches Playwright's chromium so the first MCP call is instant
4. `npm install` in `.opencode/plugin/` for the Phoenix bridge OTel deps
5. Generates `~/.config/opencode/opencode.json` from the repo's
   `opencode.json`, rewriting relative plugin paths to absolute so
   OpenCode loads the plugin regardless of which directory it's launched
   from

Step 5 is the reason the deployed config isn't a plain symlink. The
repo's `opencode.json` uses a relative plugin path (`./...`) so it stays
valid in place; the deployed copy is generated with that path resolved
to an absolute one. Edits to the repo's `opencode.json` need a re-run
of `./install.sh` to take effect.

## Verify

```sh
# Local model reachable
curl -s http://framework:11434/v1/models | jq '.data[].id'

# SearXNG instance answers JSON
curl -s 'https://searxng.n0n.io/search?q=test&format=json' | jq '.results | length'
```

Then in opencode:

```
opencode
> /mcp        # should list playwright and searxng as connected
> search the web for "qwen3-coder benchmarks"
> open https://example.com and tell me the H1
```

## Phoenix tracing

The plugin at `.opencode/plugin/phoenix-bridge.js` boots an OpenTelemetry
SDK on OpenCode startup and ships every span to Phoenix on the Framework
Desktop. With `experimental.openTelemetry: true` (already set in
`opencode.json`), OpenCode emits Vercel AI SDK spans that Phoenix renders
as a per-turn waterfall: user prompt → main agent's `ai.streamText` →
each tool call (built-in + MCP) with token counts and latencies inline.

The plugin uses `@opentelemetry/exporter-trace-otlp-proto` (not `-http`)
because Phoenix's OTLP receiver only speaks protobuf — the JSON variant
returns 415.

Spans go to Phoenix only. Earlier versions of this plugin dual-exported
to OpenLIT as well, but OpenLIT's container doesn't currently host an
OTLP receiver — the failing exporter cascaded into OpenCode's tool-call
parsing pipeline and broke tool use. Re-enable once `openlit.yml` adds
an `otel-collector` sidecar.

Defaults can be overridden via env vars (set before launching opencode):

| Variable | Default | Purpose |
|---|---|---|
| `PHOENIX_OTLP_ENDPOINT` | `http://framework:6006/v1/traces` | Phoenix HTTP target |
| `PHOENIX_SERVICE_NAME` | `opencode` | Phoenix project name |
| `PHOENIX_OTEL_DEBUG` | unset | `1` to surface OTel internal logs |

### Verifying

```sh
: > /tmp/phoenix-bridge.log    # truncate prior runs
opencode                       # any directory; CWD doesn't matter
tail -f /tmp/phoenix-bridge.log
```

Healthy startup looks like:
```
plugin function entered
endpoint=http://framework:6006/v1/traces serviceName=opencode
OTel imports resolved
sdk.start() returned
tracer obtained
boot span emitted (will flush within ~5s)
```

Then open <http://framework:6006/projects> — an `opencode` project should
appear with at least one `phoenix-bridge.boot` span. Send a prompt in
OpenCode and real LLM-call traces follow.

If the plugin's deps aren't installed, OpenCode logs a warning and the
plugin no-ops — the rest of OpenCode still works fine.

### Known limitations

- **Subagent nesting is best-effort.** The plugin opens a parent span
  per session and tries to stitch child sessions (Task-tool subagents)
  under their parent, but Vercel AI SDK spans live in their own OTel
  trace context. Until [sst/opencode#6142](https://github.com/sst/opencode/issues/6142)
  exposes `sessionID` in the `chat.system.transform` hook, child-session
  spans may show as separate traces in Phoenix.
- **Console output from plugins is swallowed by OpenCode's TUI.** That's
  why init progress goes to `/tmp/phoenix-bridge.log` rather than stdout.

## Notes

- **SearXNG JSON output** must be enabled on the instance for the MCP
  server to work. If `format=json` returns HTML or 403, edit
  `settings.yml` on the SearXNG box: `search.formats: [html, json]`,
  restart.
- **Playwright first-run** downloads ~200 MB of browser binaries into
  `~/Library/Caches/ms-playwright/`. Subsequent runs are instant.
- **Tool-calling reliability** with Qwen3-Coder is decent but not
  Claude-grade. If a tool call hangs or returns malformed JSON, the
  model is the culprit, not the MCP. Worth trying the same prompt
  against a hosted Claude or GPT-5 to confirm before debugging the
  server.
- **Adding more MCP servers**: drop another entry under the `mcp` key
  using the same `type/command/enabled` shape. The
  [official MCP registry](https://registry.modelcontextprotocol.io/)
  and [Awesome MCP Servers](https://mcpservers.org/) catalog options.