Bug: Antigravity IDE cannot be intercepted on macOS Sequoia 15.6 (Intel) although MITM is fully configured

[nophagundol-git]

Environment
OS: macOS Sequoia 15.6
Architecture: Intel x86_64
9Router: v0.5.15
Antigravity IDE: v1.107.0
Installation: Official release
Browser: Brave (only used for accessing the dashboard)
Problem

9Router starts normally and all setup steps appear successful:

MITM Server: ✅ Running
Certificate: ✅ Trusted
Hosts entries: ✅ Added
API endpoint: ✅ Working (localhost:20128)
Models endpoint: ✅ Working

However, Antigravity IDE never routes its traffic through 9Router.

The dashboard keeps showing:

DNS antigravity: inactive

and no requests ever reach the MITM server.

Verified Configuration
API is working
curl http://localhost:20128/v1/models

returns:

{
"object":"list",
"data":[
{
"id":"combo"
}
]
}
Hosts file
127.0.0.1 cloudcode-pa.googleapis.com
127.0.0.1 daily-cloudcode-pa.googleapis.com
Ping
ping cloudcode-pa.googleapis.com

returns

127.0.0.1
DNS cache
dscacheutil -q host -a name cloudcode-pa.googleapis.com

returns both

127.0.0.1

and

2001:4860:....
MITM

Dashboard shows

Certificate : Trusted
MITM Server : Running
Port check
sudo lsof -iTCP:443

shows

node (9router) LISTEN *:443
Actual Behavior

Antigravity IDE still connects directly to Google.

Example:

language_server_macos_x64
-> 34.xx.xx.xx:443

Antigravity IDE
-> 151.xx.xx.xx:443

instead of

Antigravity
-> 127.0.0.1:443

No request appears in 9Router logs.

Additional Findings

PF is disabled.

sudo pfctl -s info

returns

Status: Disabled

No redirect rules exist.

sudo pfctl -sr

returns only Apple's default anchors.

Expected Behavior

Once

hosts entries exist,
certificate is trusted,
MITM server is running,

Antigravity should connect through the local MITM proxy and requests should appear in 9Router.

Possible Cause

This seems to be related to Electron/Chromium on macOS Sequoia.

Although /etc/hosts resolves correctly, Antigravity still establishes HTTPS connections directly to Google's IP addresses.

It looks like Electron may be bypassing /etc/hosts (possibly via Async DNS / Happy Eyeballs / IPv6).

Because of that:

DNS status remains inactive
MITM never receives requests
Antigravity communicates directly with Google
Suggestion

It may help to:

verify DNS using dns.lookup() instead of only checking /etc/hosts
add a fallback for Electron's internal DNS resolver
verify IPv6 interception
automatically detect when Chromium bypasses /etc/hosts
investigate whether PF/network redirection should be enabled on macOS Sequoia
Reproducibility

Occurs 100% consistently on:

macOS Sequoia 15.6
Intel Mac
Antigravity IDE 1.107.0
9Router 0.5.15

I can provide:

Console logs
MITM logs
lsof
pfctl
/etc/hosts
DNS resolution outputs
Screen recordings

if needed for debugging.