Manage Opencode Tracing

Setup opencode Tracing

Configure OpenInference tracing for opencode terminal coding sessions to Arize AX (cloud) or Phoenix (self-hosted). Unlike the other harnesses in this repo, opencode loads its extensions in-process inside its Bun runtime — there is no per-event subprocess. The integration ships as a small TypeScript plugin shim that pulls snapshots via the opencode SDK and spawns a Python reconciler (arize-hook-opencode) which emits spans. Spans are sent directly to the backend from the reconciler — no separate buffer/collector service is required.

How to Use This Skill

This skill follows a decision tree workflow. Start by asking the user where they are in the setup process:

1. Is the harness already installed?

   • Check ~/.config/opencode/plugin/arize-tracing.ts for the Arize plugin shim
   • Check ~/.arize/harness/config.json for the harnesses.opencode block
   • If both are present -> Jump to Validate or Troubleshoot

2. Do they already have credentials?

   • Yes -> Jump to Configure Settings
   • No -> Continue to step 3

3. Which backend do they want to use?

   • Phoenix (self-hosted) -> Go to Set Up Phoenix
   • Arize AX (cloud) -> Go to Set Up Arize AX

4. Are they troubleshooting?

   • Yes -> Jump to Troubleshoot

Important: Only follow the relevant path for the user's needs. Don't go through all sections.

Set Up Phoenix

Phoenix is self-hosted. No Python dependencies are needed for tracing -- spans are sent directly via send_span() using stdlib urllib.

Install Phoenix

Ask if they already have Phoenix running. If not, walk through:

# Option A: pip
pip install arize-phoenix && phoenix serve

# Option B: Docker
docker run -p 6006:6006 arizephoenix/phoenix:latest

Phoenix UI will be available at http://localhost:6006. Confirm it's running:

curl -sf http://localhost:6006/v1/traces >/dev/null && echo "Phoenix is running" || echo "Phoenix not reachable"

Then proceed to Configure Settings with the Phoenix endpoint.

Set Up Arize AX

Arize AX is available as a SaaS platform or as an on-prem deployment. Users need an account, a space, and an API key.

First, ask the user: "Are you using the Arize SaaS platform or an on-prem instance?"

• SaaS -> Uses the default endpoint (otlp.arize.com:443). Continue below.
• On-prem -> The user will need to provide their custom OTLP endpoint (e.g., otlp.mycompany.arize.com:443). Ask for it and note it for the Configure Settings step.

1. Create an account

If the user doesn't have an Arize account:

• SaaS: Sign up at https://app.arize.com/auth/join
• On-prem: Contact their administrator for access to the on-prem instance

2. Get Space ID and API key

Walk the user through finding their credentials:

1. Log in to their Arize instance (https://app.arize.com for SaaS, or their on-prem URL)
2. Click Settings (gear icon) in the left sidebar
3. The Space ID is shown on the Space Settings page
4. Go to the API Keys tab
5. Click Create API Key or copy an existing one

Both api_key and space_id are required for the shared config.

No Python dependencies are needed. Both Phoenix and Arize AX use HTTP/JSON -- no additional Python dependencies are needed.

Then proceed to Configure Settings. If the user is on an on-prem instance, remind them to provide their custom endpoint.

Configure Settings

Important: Users must run this setup before tracing will work. The send_span() function requires ~/.arize/harness/config.json to exist for backend credential resolution.

Ask the user for:

1. Backend choice: Phoenix or Arize AX
2. Credentials (only if no existing config):
   • Phoenix: endpoint URL (default: http://localhost:6006), optional API key
   • Arize AX: API key and Space ID
3. OTLP Endpoint (Arize AX only, optional): For hosted Arize instances using a custom endpoint. Defaults to otlp.arize.com:443.
4. Project name (optional): defaults to "opencode", stored under harnesses.opencode.project_name
5. User ID (optional): Set ARIZE_USER_ID env var to identify spans by user (useful for teams)

Write the config

The config file at ~/.arize/harness/config.json is the single source of truth for backend credentials and per-harness settings. Create the directory structure if needed: mkdir -p ~/.arize/harness/{bin,run,logs,state/opencode}

Important: read-merge-write. If ~/.arize/harness/config.json already exists, read it first, then merge in the new or updated fields (e.g., add/update the harnesses.opencode entry) while preserving existing backend credentials. Only prompt for backend credentials if no existing config is found.

Phoenix:

{
  "harnesses": {
    "opencode": {
      "project_name": "opencode",
      "target": "phoenix",
      "endpoint": "<endpoint>",
      "api_key": ""
    }
  }
}

If Phoenix requires authentication (e.g. Phoenix Cloud), set the API key here under api_key, or export PHOENIX_API_KEY in the environment — it is sent as a Authorization: Bearer <key> header. The env var takes precedence over the config value. Leave api_key: "" for an unauthenticated local Phoenix.

Arize AX:

{
  "harnesses": {
    "opencode": {
      "project_name": "opencode",
      "target": "arize",
      "endpoint": "otlp.arize.com:443",
      "api_key": "<key>",
      "space_id": "<id>"
    }
  }
}

If the user has a custom OTLP endpoint, set it in harnesses.opencode.endpoint.

Activate the opencode plugin

opencode auto-discovers plugins under ~/.config/opencode/plugin/ (config docs) — there is no opencode.json edit and no host settings file to register. The installer drops the Arize plugin shim at ~/.config/opencode/plugin/arize-tracing.ts; opencode picks it up on next launch.

Install or reinstall via the installer:

./install.sh opencode

To uninstall:

./install.sh uninstall opencode

Uninstall deletes the plugin file at ~/.config/opencode/plugin/arize-tracing.ts (only if it carries the Arize header marker — the installer never touches the user's own plugins) and removes the harnesses.opencode block from ~/.arize/harness/config.json.

Validate

1. Config exists: Run cat ~/.arize/harness/config.json to verify the config file exists and has correct backend credentials under harnesses.opencode.
2. Phoenix (if applicable): Run curl -sf <endpoint>/v1/traces >/dev/null to check connectivity.
3. Plugin installed: Verify ~/.config/opencode/plugin/arize-tracing.ts exists and starts with the Arize header marker.
4. Reconciler entry point: Verify the reconciler binary exists at ~/.arize/harness/venv/bin/arize-hook-opencode (or ~/.arize/harness/venv/Scripts/arize-hook-opencode.exe on Windows). The shim spawns this binary by absolute path — it does not rely on PATH resolution. install.sh installs it as a venv entry point.

Confirm

Tell the user:

• Config saved to ~/.arize/harness/config.json
• opencode plugin shim installed at ~/.config/opencode/plugin/arize-tracing.ts
• opencode auto-discovers the plugin on next launch — no opencode.json edit required
• Spans are sent directly to the backend from the reconciler — no background process needed
• After saving, open a new opencode session and traces will appear in their Phoenix UI or Arize AX dashboard under the project name
• Mention ARIZE_DRY_RUN=true to test without sending data (set as env var before launching opencode)
• Mention ARIZE_VERBOSE=true for debug output
• Errors and reconciler stderr are always written to ~/.arize/harness/logs/opencode.log (the adapter redirects Python stderr there via ARIZE_LOG_FILE); set ARIZE_VERBOSE=true in the shell before launching opencode to also capture routine reconciler activity (snapshot ingest, span emits, dedup hits)
• Toggle tracing on/off via ARIZE_TRACE_ENABLED env var (must be exported in the user's shell before launching opencode — the shim and reconciler inherit host env vars)
• Tail the log file at ~/.arize/harness/logs/opencode.log for real-time debugging
• Mention ARIZE_TRACE_DEBUG=true to dump raw snapshot payloads under ~/.arize/harness/state/debug/ (files are named opencode_reconcile_<ts>.json / opencode_close_<ts>.json) for inspection

Architecture (How spans are produced)

opencode is fundamentally different from every other harness in this repo: extensions are plugins loaded in-process inside opencode's Bun runtime. The Arize integration is split into two pieces:

1. TypeScript plugin bridge at ~/.config/opencode/plugin/arize-tracing.ts. On message.updated (assistant completed) and session.idle it pulls the authoritative root snapshot via client.session.messages({ path: { id } }) (see the opencode SDK docs), follows completed task metadata to fetch authoritative child-session snapshots, validates session ownership, then spawns arize-hook-opencode detached and pipes the combined snapshot to stdin.
2. Python snapshot reconciler (arize-hook-opencode). Reads the snapshot, reconstructs Turn → LLM → TOOL → AGENT → child LLM/TOOL, and emits only new spans deduped by message ID, tool callID, and child session ID. opencode's AssistantMessage already carries final, cumulative tokens and cost, so no per-delta coalescing is needed.

Span tree

Each trace covers one turn (one user prompt → the assistant's response → session.idle) and preserves the requesting-message and subagent hierarchy:

Timestamps come from opencode's own message and tool clocks rather than tracing-process wall time.

Troubleshoot

Common issues and fixes for opencode: