rugged-gemini: Skill for Claude Code

Logging and Observability Principles

⚠️ All operations MUST be logged per Logging and Observability Mandate GEMINI.md § Logging and Observability Mandate.

Log Levels

Level	When	Examples
TRACE	Extremely detailed diagnostics	Fn entry/exit, var states (dev only)
DEBUG	Detailed flow for debugging	Query exec, cache hits, state transitions
INFO	General informational	Request started, task created, login
WARN	Potentially harmful	Deprecated API, fallback, retry
ERROR	Error, app continues	Request failed, API timeout, validation
FATAL	Severe, causes shutdown	DB unreachable, critical config missing

Rules

1. Every operation logs start + success/error:

log.Info("creating task",
"correlationId", correlationID,
"userId", userID,
"title", task.Title,
)

log.Info("task created successfully",
"correlationId", correlationID,
"taskId", task.ID,
"duration", time.Since(start),
)

log.Error("failed to create task",
"correlationId", correlationID,
"error", err,
"userId", userID,
)

2. Context fields: correlationId (UUID), userId, duration (ms), error.

3. Structured only:

// ✅ Structured
log.Info("user login", "userId", userID, "ip", clientIP)

// ❌ String formatting
log.Info(fmt.Sprintf("User %s logged in from %s", userID, clientIP))

4. Never log: passwords, API keys, tokens, credit cards, PII (sanitize if needed), full req/res bodies.

5. Never log in hot paths: tight loops, per-item batch processing, latency-critical sync paths. Use logger middleware redaction (pino-redact, zap masking).

Language Implementations

Go (slog):

import "log/slog"

logger := slog.New(slog.NewJSONHandler(os.Stdout, &slog.HandlerOptions{
  Level: slog.LevelInfo,
}))

logger.Info("operation started",
  "correlationId", correlationID,
  "userId", userID,
)

TypeScript (pino):

import pino from 'pino';

const logger = pino({
  level: process.env.LOG_LEVEL || 'info',
});

logger.info({
  correlationId,
  userId,
  duration: Date.now() - startTime,
}, 'task created successfully');