Tag: mcp

Claude Code, Cursor, and the GitHub Copilot coding agent all ship host allowlists for outbound traffic, and all three default to something looser than you want. The exact settings keys, a policy you can copy, and the four surfaces the allowlist does not cover.

The legacy HTTP+SSE transport used two endpoints and a sticky connection. Streamable HTTP uses one. Here is the step-by-step migration for the TypeScript and Python SDKs, the client configs you have to repoint, and the proxy buffering gotcha that makes the new endpoint look broken.

Claude Code compacts, then a single oversized file read or tool result immediately refills the window and it compacts again. Drop the item with /clear, read files in slices, and force big output to disk.

An MCP server on Node 16 warns EBADENGINE at install, then dies with 'fetch is not defined' on the first tool call. Upgrade to Node 18+ (20+ for the 2.x SDK) or polyfill the web globals.

Claude Code logs every MCP server stderr line at [ERROR] and marks working servers as failed. If your tools still run, it is cosmetic. Here is how to confirm it and quiet the noise.

One trailing comma or unescaped Windows path in your MCP config makes every server vanish, not just the broken one. Validate the JSON, fix the five usual suspects, restart.

Commit .cursor/mcp.json for the IDE, register shared servers under Dashboard > Integrations & MCP for cloud agents, and keep secrets out of git with ${env:...}. The full two-surface setup for Cursor 3.11 (July 2026), including why the repo file alone does not reach cloud agents.

A step-by-step checklist for lifting a hand-rolled Anthropic tool-calling loop onto a standalone MCP server. The tool bodies move almost verbatim; what changes is where the schema comes from, how results are wrapped, and how errors cross the process boundary.

A step-by-step checklist for moving an existing LangChain agent off inline @tool functions onto a standalone MCP server that any client can call. Covers extracting tools into FastMCP, re-wiring the agent with langchain-mcp-adapters MultiServerMCPClient, the sync-to-async switch, transports, and the gotchas that bite mid-cutover.

Build a skill to change how Claude works, a subagent to protect your context window, and an MCP server to reach a system Claude cannot otherwise touch. They solve three different problems, not one. Here is the decision, the mechanics, and the config for each.