HTTP (streamable) transport ignores httpHeaders config

[jimmynail]

Bug

The http (streamable HTTP) transport does not pass httpHeaders from the config to the MCP client. This causes authentication failures when connecting to MCP servers that require Bearer token auth (e.g., Omni).

Root Cause

In internal/mcp/client.go, the SSE transport correctly passes headers:

case "sse":
    hdr := make(http.Header)
    for k, v := range resolvedHeaders {
        hdr.Set(k, v)
    }
    mcpClient, err = NewSSEMCPClientWithRetry(addressOrCommand, hdr, mcpLogger)

But the HTTP transport ignores them:

case "http":
    mcpClient, err = client.NewStreamableHttpClient(addressOrCommand)

Fix

The mcp-go library (v0.43.1) already supports WithHeaders:

case "http":
    headers := make(map[string]string)
    for k, v := range resolvedHeaders {
        headers[k] = v
    }
    mcpClient, err = client.NewStreamableHttpClient(addressOrCommand, transport.WithHeaders(headers))

Config

{
  "mcpServers": {
    "omni": {
      "transport": "http",
      "url": "https://example.com/mcp/https",
      "httpHeaders": {
        "Authorization": "Bearer ${API_KEY}"
      }
    }
  }
}

This config works for SSE but not HTTP transport.