docs: remove SSH environment forwarding guidance

content/manuals/ai/sandboxes/integrations/_index.md

@@ -80,6 +80,8 @@ For example, if you mount `/Users/bob/src/my-project`, select
 
 ## How SSH connections work
 
+### Managed SSH configuration
+
 `sbx setup ssh` writes a managed block to your SSH config: `~/.ssh/config` on
 macOS and Linux, or `%USERPROFILE%\.ssh\config` on Windows. The block is similar
 to the following:
@@ -97,24 +99,18 @@ Host *.sbx
     UserKnownHostsFile "~/.ssh/sbx_known_hosts"
     KnownHostsCommand "sbx" ssh known-hosts %H
     StrictHostKeyChecking yes
-    SendEnv *
 # <<< docker sandboxes (managed) <<<
 ```
 
-You don't edit this block by hand. The `User _default_user_` sentinel tells the
-daemon to log you in as the sandbox image's default user, so your host username
-is never sent.
+You don't edit this block by hand. Its key entries work as follows:
 
-`SendEnv *` offers host environment variables to the daemon, but the daemon
-accepts only variables in its `ssh.acceptEnv` allowlist. Execution-sensitive
-variables such as `PATH`, `LD_*`, and `NODE_OPTIONS` are always blocked, even
-if added to the allowlist. Accepted values apply only to the SSH session and
-aren't stored in the sandbox configuration.
+- `Host *.sbx` maps sandbox hostnames to the sandbox daemon. Application host
+  pickers don't discover individual sandbox names from this wildcard, so enter
+  the hostname, such as `demo.sbx`, manually when you configure an integration.
+- `User _default_user_` tells the daemon to use the sandbox image's default
+  user, so your host username is never sent.
 
-The `*.sbx` wildcard maps sandbox hostnames to the sandbox daemon, but it
-doesn't add individual sandbox names to application host pickers. Enter the
-sandbox hostname, such as `demo.sbx`, manually when you configure an
-integration.
+### Connection and authentication
 
 Connections don't use a network port or an SSH key:
 
@@ -128,3 +124,24 @@ Connections don't use a network port or an SSH key:
 Because SSH terminates at the daemon, no SSH server runs inside the sandbox.
 The sandbox must already be created. If it is stopped, connecting to
 `<name>.sbx` starts it automatically.
+
+### Environment variables
+
+SSH connections don't forward client environment variables into the sandbox.
+The daemon acknowledges SSH environment requests for compatibility but ignores
+their names and values.
+
+### Port forwarding
+
+SSH clients can use local port forwarding to make a service listening on the
+sandbox's loopback interface available on the host. For example, a remote
+development client can map `127.0.0.1:4321` in the sandbox to
+`127.0.0.1:55565` on the host, choosing an available host port automatically.
+Traffic passes through the SSH connection instead of a published Docker port.
+
+The sandbox daemon accepts forwarded connections only to loopback addresses in
+the sandbox, including `localhost`, `127.0.0.0/8`, and `::1`. The SSH client
+chooses the bind address for the listener on the host. A listener bound to
+`127.0.0.1` or `::1` is reachable only from the host. A client configured to
+bind to a non-loopback address can make the forwarded service reachable from
+other machines, subject to the host's network and firewall configuration.