Environment
- Node.js: v26.0.0
- OS: macOS Tahoe (arm64)
- MCP client: OpenClaw
Error
Running npx -y @superhuman/mcp-mail fails with:
[12162] Connecting to remote server: https://mcp.mail.superhuman.com/mcp
[12162] Using transport strategy: http-first
[12162] Connection error: SyntaxError: Unexpected token 'e', "e0�i��"... is not valid JSON
at JSON.parse (<anonymous>)
at parseJSONFromBytes (node:internal/deps/undici/undici:4227:19)
Analysis
The error suggests the HTTP client is receiving a compressed (gzip) response but attempting to parse it as raw JSON. The binary prefix e0�i�� looks like gzip-compressed data.
This may be a compatibility issue with Node 26's undici changes, or the MCP client needs to explicitly handle Accept-Encoding/Content-Encoding headers.
Reproduction
npx -y @superhuman/mcp-mail
Server discovery works, but connection to https://mcp.mail.superhuman.com/mcp fails.
Environment
Error
Running
npx -y @superhuman/mcp-mailfails with:Analysis
The error suggests the HTTP client is receiving a compressed (gzip) response but attempting to parse it as raw JSON. The binary prefix
e0�i��looks like gzip-compressed data.This may be a compatibility issue with Node 26's undici changes, or the MCP client needs to explicitly handle Accept-Encoding/Content-Encoding headers.
Reproduction
Server discovery works, but connection to
https://mcp.mail.superhuman.com/mcpfails.