<skill_overview>
<purpose>Produce logs that are searchable, consistent, and safe</purpose>
<triggers>
<trigger>Adding log statements</trigger>
<trigger>Choosing log levels</trigger>
<trigger>Designing structured log fields</trigger>
<trigger>Handling sensitive data in logs</trigger>
</triggers>
<sources>
<source url="https://signoz.io/guides/pino-logger/">Structured Logging Practices (Pino guide)</source>
</sources>
</skill_overview>
<log_levels>
<level name="trace">
<use_for>Very detailed diagnostics and internal state</use_for>
<production>Disabled</production>
</level>
<level name="debug">
<use_for>Development debugging, transient details</use_for>
<production>Rarely enabled</production>
</level>
<level name="info">
<use_for>Key business events and normal flow</use_for>
<production>Default</production>
<example>order.created</example>
</level>
<level name="warn">
<use_for>Recoverable issues and retries</use_for>
<production>Always enabled</production>
</level>
<level name="error">
<use_for>Failures requiring investigation</use_for>
<production>Always enabled</production>
</level>
<level name="fatal">
<use_for>Process-critical failures</use_for>
<production>Always enabled + alerts</production>
</level>
</log_levels>
<structured_logging>
<principles>
<rule>Log JSON objects, not interpolated strings</rule>
<rule>Use stable field names for queries</rule>
<rule>Keep message short and event-oriented</rule>
</principles>
<correct>
<code>
logger.info(
{ event: "order.created", orderId, userId, totalCents, durationMs },
"Order created"
);
</code>
</correct>
<incorrect>
<code>
logger.info(Order ${orderId} created for ${userId} in ${durationMs}ms);
</code>
</incorrect>
</structured_logging>
<context_fields>
<recommended>
<field>event</field>
<field>requestId</field>
<field>traceId</field>
<field>userId</field>
<field>component</field>
<field>durationMs</field>
</recommended>
</context_fields>
<sensitive_data>
<never_log>
<item>Passwords and secrets</item>
<item>Tokens, API keys, session IDs</item>
<item>Credit card numbers and CVV</item>
<item>Personal identifiers unless required</item>
</never_log>
<redaction>
<code>
function redactEmail(email: string) {
const [name, domain] = email.split("@");
return ${name.slice(0, 3)}***@${domain};
}
</code>
</redaction>
</sensitive_data>
<correlation_ids>
<rules>
<rule>Propagate requestId or traceId across async boundaries</rule>
<rule>Include correlation IDs in every log line for a request</rule>
</rules>
</correlation_ids>
<performance>
<rules>
<rule>Avoid heavy serialization for disabled levels</rule>
<rule>Do not log inside tight loops at info level</rule>
<rule>Prefer structured fields over string concatenation</rule>
</rules>
</performance>
<anti_patterns>
<avoid name="string_interpolation_only">Using only interpolated strings</avoid>
<avoid name="log_sensitive">Logging secrets or PII</avoid>
<avoid name="too_chatty">Info logs for every small operation</avoid>
</anti_patterns>
coder-typescript-logging
TypeScript/JavaScript 日志记录的最佳实践：结构化日志、日志级别、上下文信息，以及日志脱敏处理。在添加或审查日志代码时使用。
SKILL.md
--- frontmattername: coder-typescript-logging description: TypeScript/JavaScript logging best practices: structured logs, levels, context, and redaction. Use when adding or reviewing logging code.