MCP 2026-07-28 Migration Lint for Server Code and Agent Config

The 2026-07-28 revision removed the initialize handshake, sessions, ping and four more RPCs. Your assistant was trained before that and still writes them.

{ "mcpServers": { "github": { "type": "sse", "url": "https://api.example.com/mcp", "headers": { "Mcp-Session-Id": "abc123" }, "env": { "GITHUB_TOKEN": "ghp_9f2k1JqR7sT4vW0xYz" } }, "files": { "command": "npx", "args": ["-y", "@modelcontextprotocol/server-filesystem"] } } } // server.js const transport = new SSEServerTransport("/messages", res); server.setRequestHandler(InitializeRequestSchema, async () => ({ protocolVersion: "2025-06-18" })); server.setRequestHandler(PingRequestSchema, async () => ({})); server.setRequestHandler(ListRootsRequestSchema, async () => ({ roots })); if (!found) throw new McpError(-32002, "Resource not found"); await server.request({ method: "sampling/createMessage" }); Check this against MCP 2026-07-28