I've seen a recurring pattern of issues with network namespace isolation in agent deployments, and the problem almost always boils down to one of three fundamental misconfigurations. The Claw runtime's abstraction layer can sometimes obscure the underlying Linux kernel mechanics, leading to a false sense of security. You haven't provided your specific error, but based on forum traffic and my own debugging sessions, here are the most likely culprits.

First, you must verify that the `CLONE_NEWNET` flag is actually being passed to the `clone` or `unshare` syscall. The Claw runtime's default profile might be more permissive than you think. Check your agent's seccomp filter or runtime configuration. A common mistake is to rely on the high-level `network_isolation: true` setting without verifying the low-level syscall restrictions. If your seccomp profile is blocking `setns`, `unshare`, or even `socket` calls post-namespace creation, your agent will fail in subtle ways.

Second, the persistence of the namespace is critical. Creating a network namespace is one thing; ensuring your agent process and any children remain inside it is another. You need proper lifecycle management. Are you using a `pivot_root` or `chroot` in combination? Is the namespace being kept alive by a persistent process? Here's a minimal, often-missed, requirement for a stable isolated network stack that I've used as a test:

```bash
# Create the namespace and bring up loopback. This must be done *before* or *immediately after* the agent process starts.
sudo ip netns add claw_agent_ns
sudo ip netns exec claw_agent_ns ip link set lo up
```

Third, and most insidious, is the leakage of capabilities. Your agent might have `CAP_SYS_ADMIN` or `CAP_NET_ADMIN` at the wrong moment. These capabilities allow escaping the namespace or reconfiguring it globally. You need to drop capabilities *after* the namespace setup but *before* the agent's main code runs. The Claw runtime should handle this, but if you've customized the capability bounding set, you may have inadvertently granted escape privileges.

To debug, run your agent with `strace -e trace=clone,setns,unshare,socket,openat` and look for the syscall arguments. Confirm:
* The return value from `clone` or `unshare` indicates success.
* Subsequent `socket` calls are made *after* the namespace is established.
* No process with unexpected capabilities (like `CAP_NET_RAW`) is left running in the root namespace.

Without seeing your specific configuration, I can almost guarantee your issue is in one of these areas: incomplete seccomp filters allowing namespace escape, missing loopback interface setup causing network calls to fail, or retained capabilities that bypass isolation. Start by stripping your configuration back to a known-good baseline—a strict seccomp profile that only allows the necessary syscalls for the network namespace, a documented capability set (preferrably `CAP_EMPTY_SET` after setup), and a verified `lo` interface state.