MCP Is Not Good Yet — David Cramer, Sentry
Jul 3, 2025 · 16:41
David Cramer, founder and engineer at Sentry, argues that the Model Context Protocol (MCP) is a pluggable architecture for agents, not a simple API overlay, and that it is not yet good but worth experimenting with. He stresses that exposing existing OpenAPI endpoints as MCP tools yields terrible results; instead, developers must design context specifically for agents, returning Markdown rather than raw JSON to improve model reasoning. Cramer details Sentry's MCP server, built in two days using Cloudflare Workers for OAuth 2.1, and notes that remote OAuth is essential for B2B SaaS, while standard I/O introduces security risks. He highlights the need for careful token and cost management—citing a single request that produced 20 API calls to Sentry—and advocates for building dedicated agents (like Sentry's root cause analysis tool) that wrap MCP, giving the provider control over prompts, models, and error handling. Despite ongoing issues like lack of streaming responses and unstable client support, Cramer concludes that MCP's core concepts (plug-ins, agents, tools) are just familiar software patterns with new names.
