Observability

FrontMCP has native observability built in. Enable it with a single config line and get automatic distributed tracing, structured JSON logging, and per-request log collection across your entire server — every tool call, resource read, prompt invocation, auth flow, and transport session.

Capability	What It Does
OpenTelemetry tracing	Automatic spans for all 33 SDK flows with parent-child hierarchy
Structured logging	JSON log entries with trace correlation, sent to any backend
Request log collection	Per-request aggregated view of all events during a request lifecycle
`this.telemetry` API	Developer-facing API for custom spans, events, and attributes in tools
Vendor integrations	OTLP, Coralogix, Datadog, Logz.io, Grafana, winston, pino

How It Works

@FrontMcp({
  observability: true, // That's it
})

When enabled:

Zero config — 103+ hooks register automatically on every flow
Single trace ID — all spans in a request share the same W3C trace ID
Privacy-safe session ID — a truncated SHA-256 hash, never the real session ID
Zero overhead when unused — without a TracerProvider, all OTel calls are no-ops
MCP-interoperable — uses rpc.system = "mcp" and mcp.* attributes for cross-framework tracing

What Gets Instrumented

Every flow in the SDK is automatically traced:

Category	Flows
HTTP & Transport	HTTP requests, SSE sessions, Streamable HTTP, Stateless HTTP
Tools	call-tool (every stage), list-tools
Resources	read-resource, list-resources, list-templates, subscribe, unsubscribe
Prompts	get-prompt, list-prompts
Agents	call-agent (with nested tool call tracking)
Auth	auth:verify, session:verify
OAuth	token, authorize, callback, provider-callback, register
Skills	search, load, llm-txt, llm-full-txt, API
Elicitation	request, result
Other	completion, well-known endpoints, logging/set-level

Logging vs Tracing

They’re complementary, not competing:

	Logging	Tracing
What	Event stream — discrete log lines	Request lifecycle — spans with timing
Purpose	Debug, audit, error forensics	Performance analysis, dependency mapping
Export to	Stdout, winston, pino, OTLP	OTLP, Jaeger, Zipkin
Connection	`trace_id` on every log line	Native parent-child span tree

A log line says “what happened.” A span says “how long it took.” When both share the same trace_id, platforms like Coralogix or Datadog show logs inline within a trace waterfall.

Learn More

Setup Guide

Step-by-step: install, configure backends, use this.telemetry

Telemetry API Reference

Full API for TelemetryAccessor, TelemetrySpan, and testing utilities

OpenTelemetry

OpenTelemetry documentation

Plugin System

How plugins hook into the request lifecycle

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Guides

How It Works

What Gets Instrumented

Logging vs Tracing

Learn More

Setup Guide

Telemetry API Reference

OpenTelemetry

Plugin System

​How It Works

​What Gets Instrumented

​Logging vs Tracing

​Learn More

Setup Guide

Telemetry API Reference

OpenTelemetry

Plugin System

How It Works

What Gets Instrumented

Logging vs Tracing

Learn More