# launchdarkly-metric-instrument

Instruments LaunchDarkly metric events by adding track() calls across client or server code and verifies incoming events.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 3200 installs · ★ 28
- Author: launchdarkly
- License: Apache-2.0 · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/launchdarkly/ai-tooling/tree/HEAD/skills/metrics/launchdarkly-metric-instrument/SKILL.md
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/skills/launchdarkly-metric-instrument

## What it does

The skill checks whether a LaunchDarkly SDK is present and determines its runtime type. Server-side SDKs (Node.js, Python, Go, Java, Ruby, .NET) require passing a context object into every `track()` call. In client-side setups such as React, the context is configured once during client initialization.

When no SDK exists, the agent inspects lockfiles like `package-lock.json` or `poetry.lock` to install the package and set up initialization. It reuses existing context objects rather than creating new ones inline, keeping experiment targeting intact. Numeric values like latency or revenue pass through the optional `metricValue` argument.

A remotely hosted LaunchDarkly MCP server with `list-metric-events` is strictly required. Without that tool running in your setup, the agent cannot verify whether the event actually reaches LaunchDarkly.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add launchdarkly/ai-tooling --skill launchdarkly-metric-instrument -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/launchdarkly-metric-instrument/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/launchdarkly-metric-instrument/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add launchdarkly/ai-tooling --skill launchdarkly-metric-instrument -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/launchdarkly-metric-instrument/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add launchdarkly/ai-tooling --skill launchdarkly-metric-instrument -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/launchdarkly-metric-instrument/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install launchdarkly/ai-tooling launchdarkly-metric-instrument
```

2. **Manually: put the files in place**
- File: `.github/skills/launchdarkly-metric-instrument/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add launchdarkly/ai-tooling --skill launchdarkly-metric-instrument -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/launchdarkly/ai-tooling --path skills/metrics/launchdarkly-metric-instrument
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/launchdarkly-metric-instrument/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add launchdarkly/ai-tooling --skill launchdarkly-metric-instrument -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/launchdarkly/ai-tooling/tree/HEAD/skills/metrics/launchdarkly-metric-instrument/SKILL.md

## When to use it
- insert a `track()` call into an action or event handler
- detect LaunchDarkly SDK configuration and call signatures
- set up and initialize the appropriate SDK if missing
- verify event delivery in LaunchDarkly using MCP tools

## Example prompts
- Add a LaunchDarkly track call to the checkout submit handler.
- Instrument latency tracking for this backend API endpoint.
- Confirm whether `purchase-completed` events are reaching LaunchDarkly.

## Source text · SKILL.md · Apache-2.0

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 9b50fe2615a44b2a.

BEGIN THIRD-PARTY FILE 9b50fe2615a44b2a
```text
---
name: launchdarkly-metric-instrument
description: "Instrument a LaunchDarkly metric event in a codebase by adding a track() call. Use when the user wants to wire up an event, instrument an action for a metric, add tracking to a feature, or confirm that an event is flowing to LaunchDarkly."
license: Apache-2.0
compatibility: Requires the remotely hosted LaunchDarkly MCP server
metadata:
  author: launchdarkly
  version: "1.0.0-experimental"
---

# LaunchDarkly Metric Instrument

You're using a skill that will guide you through adding a `track()` call to a codebase so a LaunchDarkly metric can measure it. Your job is to detect the SDK in use, find the right place in code to add the call, write it correctly, and verify that events are reaching LaunchDarkly.

## Prerequisites

This skill requires the remotely hosted LaunchDarkly MCP server to be configured in your environment.

**Required MCP tools:**
- `list-metric-events` — verify events are flowing after instrumentation

**Optional MCP tools (enhance workflow):**
- `get-project` — retrieve the SDK key for the right environment when SDK initialization is needed

## Workflow

### Step 1: Detect the SDK

Before writing any code, understand the LaunchDarkly setup already in this codebase.

1. **Search for existing `track()` calls.** This is the fastest signal:
   - Look for `ldClient.track(`, `.track(`, `ld.track(`
   - If any exist, they tell you the SDK type, call signature, and context pattern in one shot — mirror those exactly.

2. **Search for SDK imports and initialization** if no `track()` calls exist:
   - Check `package.json`, `requirements.txt`, `go.mod`, `Gemfile`, `*.csproj` for an LD SDK dependency
   - Look for `LDClient`, `ldclient`, `launchdarkly-server-sdk`, `launchdarkly-node-server-sdk`, `launchdarkly-react-client-sdk`, etc.
   - Find the initialization block to understand how the client is accessed across the codebase

3. **Determine client-side or server-side.** This is the most critical distinction — it determines the `track()` signature:

   | SDK type | `track()` signature | Notes |
   |----------|---------------------|-------|
   | Server-side (Node, Python, Go, Java, Ruby, .NET) | `ldClient.track(eventKey, context, data?, metricValue?)` | Context required per call |
   | Client-side (React, browser JS) | `ldClient.track(eventKey, data?, metricValue?)` | Context set at init, not per call |

   See [SDK Track Patterns](references/sdk-track-patterns.md) for full examples by language.

### Step 2: Install & Initialize (if SDK not present)

Skip this step if the SDK is already in the codebase.
```
END THIRD-PARTY FILE 9b50fe2615a44b2a

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First 2618 of 8326 bytes. © launchdarkly · Apache-2.0 · https://github.com/launchdarkly/ai-tooling/tree/HEAD/skills/metrics/launchdarkly-metric-instrument/SKILL.md

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