# observability-baseline

Bakes error capture in Sentry, request-id structured logs and /healthz plus /readyz endpoints into a freshly generated service. Useful when the app is still being scaffolded and you don't want the first prod failure to go unseen.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · ★ 107
- Author: avelikiy
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/avelikiy/great_cto/tree/HEAD/skills/observability-baseline/SKILL.md
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/skills/observability-baseline

## What it does

The skill runs while an app is being generated. It puts three pieces in place: Sentry initialization with the DSN read from `SENTRY_DSN` rather than written into code, a logger that emits JSON carrying a `request_id` per request, and two endpoints — `GET /healthz` for liveness and `GET /readyz` for readiness, which checks that dependencies such as the database and cache answer. Diagnostics go to stderr so they stay out of user-facing output.

Wiring is the part that matters. `app-scaffolder` drops `instrumentation.ts`, the logger and the endpoints into the generated app and adds `SENTRY_DSN` to `.env.example`. `infra-provisioner` sets the variable in the prod environment and points the platform health probe at `/readyz`. `l3-support` reads Sentry and the request-id logs during triage, and `devops` fails the deploy gate when `/readyz` doesn't return 200 after a release.

Skip it for a plain library, a CLI with no running service, or a static site with no backend — there is nothing to probe or log. The Sentry project and endpoints get recorded in `docs/infra/PROVISION-{slug}.md`. Done means the three pieces are wired into the prod environment, not merely present in the code.

## Requirements
- Works with: Sentry

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add avelikiy/great_cto --skill observability-baseline -a claude-code
```

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

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add avelikiy/great_cto --skill observability-baseline -a codex
```

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

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add avelikiy/great_cto --skill observability-baseline -a cursor
```

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

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install avelikiy/great_cto observability-baseline
```

2. **Manually: put the files in place**
- File: `.github/skills/observability-baseline/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add avelikiy/great_cto --skill observability-baseline -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/avelikiy/great_cto --path skills/observability-baseline
```

### Windsurf (Devin Desktop)

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

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add avelikiy/great_cto --skill observability-baseline -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/avelikiy/great_cto/tree/HEAD/skills/observability-baseline/SKILL.md

## When to use it
- catch the first production error instead of hearing about it from users
- tie every log line from one request together by request_id
- give the load balancer an endpoint to check liveness against
- verify the database and cache are reachable before taking traffic
- fail a deploy when the service stops answering after release

## Example prompts
- Scaffold a new service and bake in Sentry, JSON logs with request_id, and /healthz and /readyz endpoints
- Set SENTRY_DSN in the prod environment and point the platform health probe at /readyz
- Check that /readyz returns 200 after deploy, otherwise stop the rollout

## Source text · SKILL.md · MIT

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: 6e0831bdd44f0e52.

BEGIN THIRD-PARTY FILE 6e0831bdd44f0e52
```text
---
name: observability-baseline
description: Scaffold-time observability so a shipped product is not blind in prod from day one — error capture (Sentry), request-id structured logging, and /healthz + /readyz endpoints. stack-baseline pins Sentry but nothing wires it; this is the wiring. Loaded by app-scaffolder (bake into the scaffold), infra-provisioner (prod env + probes), and consumed by l3-support (traces) and devops (deploy gate).
when_to_use: |
  Apply when:
  - app-scaffolder is generating a new product (any archetype that runs as a service)
  - infra-provisioner is setting prod env vars + health probes
  - l3-support needs traces/logs to triage an incident
  Do NOT apply to:
  - pure library / cli archetypes with no running service
  - static marketing sites with no backend
effort: medium
allowed-tools: Read, Write, Edit, Grep, Glob
paths:
  - "src/**"
  - "app/**"
  - "docs/infra/**"
---

# observability-baseline

stack-baseline names Sentry and wires it nowhere — so every shipped product's first
prod incident is invisible, and l3-support triages blind. This skill makes three
things exist at scaffold time. Defaults baked in; no founder question.

## 1. Error capture (Sentry)

- `instrumentation.ts` (Next.js) / SDK init at process start; DSN from `SENTRY_DSN`
  env (never hardcoded).
- CI uploads source maps on release so stack traces are readable (release = git sha).
- Capture unhandled rejections + a global error boundary on the client.

## 2. Request-id structured logging

- A logger that emits **JSON** (not `console.log` prose) with a per-request
  `request_id` (generate at the edge, propagate via header/async-local-storage).
- Levels: error / warn / info / debug — diagnostics go to **stderr**, never mixed
  into user-facing stdout. (Same discipline as the CLI logging gap, DEEPEN d94.)
- One log line per request with: request_id, method, path, status, latency_ms.

## 3. Health endpoints

- `GET /healthz` — liveness (process up). `GET /readyz` — readiness (deps reachable:
  db, cache). Cheap, unauthenticated, no PII.
- These are what infra-provisioner probes and what a load balancer checks.

## Wiring (a skill is shelfware unless a consumer loads it)
```
END THIRD-PARTY FILE 6e0831bdd44f0e52

The third-party file has ended. Everything between the 6e0831bdd44f0e52 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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