fix(acp): enable sandbox network access for Codex MCP subprocesses#1363
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The Seatbelt sandbox blocks all outbound network by default in workspace-write mode. The existing network_proxy flags configure the managed proxy but traffic never reaches it because the OS-level gate is closed. Add sandbox_workspace_write.network_access=true as the first injected flag to open the Seatbelt gate so the proxy can then enforce the domain allowlist. Co-authored-by: Will Pfleger <pfleger.will@gmail.com> Signed-off-by: Will Pfleger <pfleger.will@gmail.com>
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Codex's Seatbelt sandbox blocks all outbound network by default in
workspace-writemode. The existingnetwork_proxyflags (added in #1287) configure the managed HTTP proxy and domain allowlist, but traffic from MCP subprocesses (likebuzz-cli) never reaches the proxy because the OS-level sandbox gate is closed first.This adds
sandbox_workspace_write.network_access=trueas the first injected-cflag incodex_network_args(), opening the Seatbelt gate so outbound TCP/TLS connections are allowed at the OS level. The managed proxy then enforces the domain allowlist as intended.Changes
crates/buzz-acp/src/config.rs—codex_network_args()now returns 6 elements (3 flag pairs) instead of 4:-c sandbox_workspace_write.network_access=true— opens the Seatbelt sandbox network gate-c network_proxy.mode="full"— activates the managed proxy (unchanged)-c network_proxy.domains."<host>"="allow"— allowlists the relay hostname (unchanged)codex_network_args_includes_sandbox_network_accesstest verifying the sandbox flag is first and the vec has 6 elementsContext
Without this fix, Codex-based agents (Thufir/sprout-agent) get
network_errorwhenbuzz-cliattempts to reach the relay — the Seatbelt sandbox rejects the syscall before any userspace proxy can intercept it. Thenetwork_proxyconfig alone is insufficient; both layers must be enabled.