MCPcat – A free open-source library for MCP server monitoring
Hey everyone! We've been working with several MCP server maintainers and we noticed some difficulties getting drop-in logging and identity attribution working out of the box with existing vendors. A couple of challenges we hoped to solve were: - Baseline piping of tool calls to traditional vendors - How to tie tool calls to a “user session” - Understanding the context behind tool calls made by agents So we built something. :) The MCPcat library is completely free to use, MIT licensed, and provides a one-line solution for adding logging and observability to any vendor that supports…
MCPcat – A free open-source library for MCP server monitoring launched on August 28, 2025 with 14 votes, #881 of 8,530 launches that month and more than 75% of that year's launches. The site was still online in September 2026, 1 year on.
In plain words
MCPcat is a free, MIT-licensed library that adds logging and observability to MCP servers with a single line of code. It captures tool calls, tracks user sessions, and provides context for agent actions, then pipes this data to monitoring vendors via OpenTelemetry. The library includes built-in support for Datadog and Sentry, making it easy for MCP server maintainers to implement drop-in observability without complex setup.
written from the facts on this page · September 2026
From the sources
AgentCat is an analytics platform for MCP server owners 🐱. - agentcathq/agentcat-typescript-sdk
In the maker’s words, at launch
Hey everyone! We've been working with several MCP server maintainers and we noticed some difficulties getting drop-in logging and identity attribution working out of the box with existing vendors. A couple of challenges we hoped to solve were: - Baseline piping of tool calls to traditional vendors - How to tie tool…
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MCP Server for OpenTelemetryNov 2025 · github.com · ▲13Hey HN, Gal, Nir and Doron here. Over the past 2 years, we've helped teams debug everything from prompt issues to production outages. We kept running into the same problem: Jumping between our IDEs and our observability dashboards. So, we built an open-source MCP server that connects any OpenTelemetry backend (Grafana, Jaeger, Datadog, Dynatrace, Traceloop) to our dev environment using an MCP. While there are many MCP servers built for specific providers (like Datadog’s - https://docs.datadoghq.com/bits_ai/mcp_server), they’re closed source (so we can’t easily extend…
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Source: Show HN post ↗ · launch text quoted in part
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