Observability

What it does

When your agent uses it

• Reviewing logging
• Tracing in an application
• A production problem cant be diagnosed from the signals that exist today

Example prompts

• “t be diagnosed from the signals that exist today. Triggers: user says”
• “tracing”
• “metrics”
• “/observability”

Requirements

• Node.js

Workflow steps

8 steps, taken from the first numbered list in SKILL.md.

1. 1Use the project's existing logger and conventions; find how a neighbouring
2. 2Log structured events, not sentences: a stable event name plus fields
3. 3Levels mean something: error needs a human, warn is degraded but
4. 4Correlate: carry a request or trace id through async boundaries
5. 5Never log secrets, tokens, credentials, or personal data. Configure redaction
6. 6Log an error once, where it is handled, with the error object and context —
7. 7Metrics use bounded label values. User ids, raw URLs, and error messages as
8. 8Trace the I/O: spans around outbound HTTP, database, queue, and cache calls,

What it can do on your machine

Read from SKILL.md and the folder at commit 57f6018. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are typescript).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Observability loads about 1.2k tokens when it runs. Until then it costs about 95 tokens; SKILL.md has 450 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~95

When it runs · the whole SKILL.md, loaded when a task matches

~1.2k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from WrongStack/WrongStack at commit 57f6018, republished under its MIT licence (© WrongStack). 450 words, ~1,222 tokens.

name

observability

description

Use this skill when adding or reviewing logging, metrics, or tracing in an application, or when a production problem can't be diagnosed from the signals that exist today. Triggers: user says "logging", "logs", "trace", "tracing", "metrics", "observability", "instrument", "OpenTelemetry", "structured logging", "log level", "correlation id", "monitoring", "alert".

version

2.0.0

required-capabilities

filesystem.read, filesystem.write

optional-capabilities

code.inspect

// Redaction configured once, at the logger.
const logger = pino({
  level: process.env.LOG_LEVEL ?? 'info',
  redact: ['req.headers.authorization', 'req.headers.cookie', '*.password', '*.token'],
});

// One structured event, with correlation and the error object.
try {
  await chargeCard(order);
  logger.info({ orderId: order.id, durationMs: Date.now() - started }, 'order.charged');
} catch (err) {
  logger.error({ err, orderId: order.id, traceId: currentTraceId() }, 'order.charge_failed');
  throw new PaymentError('charge failed', { cause: err });
}

// A span around an outbound dependency.
const tracer = trace.getTracer('checkout');

export async function reserveStock(sku: string, qty: number): Promise<void> {
  await tracer.startActiveSpan('inventory.reserve', async (span) => {
    span.setAttributes({ 'inventory.sku': sku, 'inventory.qty': qty });
    try {
      await inventoryClient.reserve(sku, qty);
    } catch (err) {
      span.recordException(err as Error);
      span.setStatus({ code: SpanStatusCode.ERROR });
      throw err;
    } finally {
      span.end();
    }
  });
}

© WrongStack, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file in packages/core/skills/observability of WrongStack/WrongStack.

• SKILL.md
• SKILL.save.md

Open the folder on GitHubat commit 57f6018