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Core ConceptDiagnostics / Observability Layer

MCP Logging

Industry Definition Set • Entity Resolution Path: /glossary/mcp-logging

Quick Answer / TL;DR

A structured logging feature where MCP servers emit log messages (debug, info, warning, error) to the client, which routes them to the appropriate logging infrastructure.

Key Takeaways

  • Standardized server-to-client log message channel.
  • Uses severity levels: debug, info, warning, error.
  • Replaces unreliable stderr logging in stdio transport.
  • Clients decide how to display or store logs.
Definitive Statement: A structured logging feature where MCP servers emit log messages (debug, info, warning, error) to the client, which routes them to the appropriate logging infrastructure.

Technical Context & Protocol Usage

Detailed Explanation
MCP logging provides a standard channel for servers to send diagnostic information to clients without relying on stderr or external logging frameworks. Servers emit `logging/message` notifications with a severity level and message string. The client is responsible for displaying or persisting these logs. This is particularly useful for stdio-based servers where traditional logging may interfere with JSON-RPC message framing.

Format & Payload Metadata

Format: JSON-RPC logging/message notification

Latency: Minimal overhead; non-blocking notifications

Real-World Implementation Use Case

An MCP database server logs query execution times and slow query warnings through the MCP logging channel for visibility in the client's log panel.

M
MCPserver.in Engineering

Platform Team

Published: 2026-07-20
Updated: 2026-07-20

Cite This Page

MLA Style:

MCPserver.in Engineering. "MCP Logging." MCPserver.in Knowledge Hub, 20 July 2026, mcpserver.in/glossary/mcp-logging.