Records a design session on MCP server deployment as a standalone
amendment, ahead of folding it into the spec:
- Every agent gets its own VM, justified by inter-agent isolation and
per-agent credential attribution; Docker-in-Docker stays as an extra
Dev Agent reason rather than the rule's foundation
- Egress is a declared, per-agent-instance default-deny allowlist,
covering what MCP servers reach on the agent's behalf, with the
tailnet's 100.64.0.0/10 called out as outside RFC1918
- MCP servers run per agent VM, one instance per (service, site,
privilege), with site in the server identity rather than a tool
argument
- Third-party MCP images are digest-pinned and excluded from Watchtower
- Routed meta-tools rejected; stateful-server relocation parked
Two consequences settled with the operator while drafting: each MCP
server instance gets its own Vaultwarden machine account (A7), and any
write, reversible or not, requires an approved plan (C2).
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
dongarandClaude Opus 5.5
31bef59151