shadow-testandClaude Opus 5
3bd3caa101
The toggle grants CAP_NET_ADMIN and /dev/net/tun and stops there, which users reasonably read as "turn the VPN on" — the gap between the two is the reported bug that the default network does not route through a VPN. Close it by giving the container an agent-usable way to build the tunnel, rather than leaving each project to rediscover it. container/skills/ is baked to /opt/triple-c-skills and installed into ~/.claude/skills/ by entrypoint.sh from VPN_SUPPORT_ENABLED, mirroring how Mission Control installs its own. Staged under /opt because ~/.claude is a volume mount that would mask an image copy from first start. Three details that are not incidental: - The variable is sent as 0 rather than omitted when off, because ~/.claude persists: entrypoint has to be *told* to remove a skill left by an earlier run with the toggle on, and an absent variable cannot say that. A stale skill is worse than none, since it instructs an agent to use a capability the container no longer has. - It is reserved in RESERVED_ENV_EXACT alongside MISSION_CONTROL_ENABLED, or a custom env var of the same name could claim the skill without the capability behind it. Covered by a test. - The skill is re-copied on every start, rm -rf'd first, so fixes reach existing projects and files dropped from a later version do not linger. The skill itself carries the three things that are easy to get wrong: that a full tunnel captures the Docker resolver and takes DNS down with it, that an IP-literal health check cannot see a dead resolver, and that no tunnel survives a restart while /run state riding the snapshot makes it look as though one did. It also states what it deliberately does not do — no killswitch, no autostart — so an agent proposes those as decisions rather than improvising them. pia-wg.sh preflights CAP_NET_ADMIN by capability bit rather than letting the first `ip` call fail with a bare EPERM that points nowhere near the setting that needs changing. Credentials stay in a file (~/pia-creds, PIA_CREDS to override) rather than the environment, where docker inspect and every process in the container would see them. Tested: install/refresh/remove/no-op paths of install_feature_skill against the real function; preflight with and without the capability; and a full up --full / down round trip, confirming DNS via PIA's resolvers, api.anthropic.com reachable through the exit, and routes and resolv.conf restored on teardown. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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name, description
| name | description |
|---|---|
| pia-vpn | Connect this container's traffic through a PIA VPN tunnel over WireGuard, or diagnose one that is not working. Use when asked to enable, route through, check, or tear down a VPN, when traffic needs to leave from a different location, or when DNS or connectivity broke after a VPN was brought up. |
PIA VPN
Bring this container's traffic out through Private Internet Access over WireGuard, using the API PIA documents for headless use.
Run sudo ~/.claude/skills/pia-vpn/pia-wg.sh with up, up --full, down or
status. Read the rest of this page before the first up --full — two of the
behaviours below are actively misleading if you meet them without warning.
Before anything else: what the toggle does not do
Triple-C's VPN support setting grants three things — CAP_NET_ADMIN, the
/dev/net/tun device, and the net.ipv4.conf.all.src_valid_mark sysctl — and
stops there. It starts no client, builds no tunnel and changes no route.
So "the VPN is enabled but traffic isn't going through it" is normally not a
fault. It means the capability is present and nothing has used it yet. Check
with status before assuming something is broken.
If the toggle is off, the script says so and names the setting. It cannot be
turned on from inside the container; the user changes it in Config → Runtime,
and it recreates the container on the next start (home and .claude volumes
are preserved — it is not a Reset).
Two modes
| routes | use when | |
|---|---|---|
up |
only 1.1.1.1/32 |
verifying the tunnel works without disturbing anything |
up --full |
all public traffic | you actually want traffic leaving via PIA |
Prefer up first. It proves the handshake, credentials and region are good
while your own connectivity is untouched, so a failure is cheap.
up --full routes Claude Code's own API traffic through PIA. If the tunnel
drops, that traffic stops until it recovers or you run down. Say so before
running it — the user may be mid-session, and they will experience the failure
as Claude going away, not as a VPN problem.
Trap 1: a full tunnel takes DNS with it
The container resolves through an address on the Docker network — under Docker
Desktop, 192.168.65.7 — which sits outside the container's own subnet. A
default route of 0.0.0.0/0, or the 0.0.0.0/1 + 128.0.0.0/1 pair, captures
it and posts every lookup into a tunnel that cannot carry private traffic.
Nothing resolves after that. The visible symptom is Claude Code reporting it
cannot connect, because api.anthropic.com no longer resolves:
$ curl https://api.anthropic.com/v1/messages
* Could not resolve host: api.anthropic.com (rc=6)
pia-wg.sh already handles this: it routes 10.0.0.0/8, 172.16.0.0/12,
192.168.0.0/16 and 169.254.0.0/16 back via the original gateway, then pins
PIA's own resolvers through the tunnel with /32 routes that outrank the
10/8 exclusion. If you ever route traffic by hand, you owe both halves — the
exclusions and a resolver reachable from wherever you pointed the default.
Trap 2: an IP-literal health check cannot see a dead resolver
curl https://1.1.1.1/cdn-cgi/trace needs no DNS, so it returns a cheerful
PIA exit address while name resolution is entirely broken. A tunnel verified
that way looks perfect and works for nothing.
status resolves a real name for this reason. Trust its DNS: line, and if
you check by hand, resolve a name rather than fetching an address.
Trap 3: no tunnel survives a restart, and it fails open
The network namespace is rebuilt every time the container starts, and nothing inside reconnects anything. After a stop/start, Reset or any config change that recreates the container, the interface and its routes are gone.
State under /run/pia-wg rides the snapshot and persists, so leftover files
make it look as though the tunnel is still configured. It is not. Traffic goes
out the real address with no error and nothing visibly different.
Never infer from /run/pia-wg that a tunnel is up. Run status — if the
handshake line is missing, there is no tunnel. Re-run up after every start.
Credentials
Two lines in ~/pia-creds — username, then password:
p1234567
your-password
Set PIA_CREDS to use a different path. Treat the contents as secret: never
print the file, never echo the values, and never include them in a commit, a
log or a message. The script reads it directly and does not echo it.
Regions
Defaults to us_chicago. Override with PIA_REGION:
sudo PIA_REGION=uk_london ~/.claude/skills/pia-vpn/pia-wg.sh up --full
List the ids:
curl -s https://serverlist.piaservers.net/vpninfo/servers/v6 \
| head -1 | jq -r '.regions[].id'
Verifying
status prints three things — handshake, DNS, and the public address:
latest handshake: 2 seconds ago
transfer: 92 B received, 180 B sent
DNS: ok (via 10.0.0.243 10.0.0.242)
public IP: 64.113.5.244
All three matter. A handshake with DNS: BROKEN is trap 1. A handshake with an
unchanged public address means routing did not take — you are probably in up
rather than up --full.
Tearing down
down restores resolv.conf from its backup and removes exactly the routes
that were added, in reverse order, then deletes the interface. It is safe to
run when nothing is up. Confirm afterwards that the public address is back to
the container's own.
What this deliberately does not do
- No killswitch. Blocking non-tunnel egress needs
iptables, which is not in the image, and would cut Claude Code's API traffic whenever the tunnel is down. If the user needs guaranteed egress rather than convenient egress, say so plainly rather than improvising one — it is a real design decision. - No autostart. There is no service manager in the container and Triple-C has no start hook, so nothing can re-establish the tunnel automatically.
- Not PIA's desktop client.
pia-daemonandpiactlare installable but cannot work headless: the daemon never accepts a client connection without the GUI, andpiactl --helpstates that connecting requires it. If you find one installed, it is not a working alternative to this script.