A connection that cannot point at the machine it is running on

"Nothing runs on the LLeMbas host" is the sentence the absent sandbox and the
absent local MCP rest on, and an SSH profile aimed at 127.0.0.1 walked straight
past it -- through a real login, with every gate in policy.py still applying,
onto the machine holding the database and the Fernet key. From the SSH layer
down it is indistinguishable from a container on the network, so nothing here
could have noticed.

One switch, three positions: never, one named port, anywhere. The middle one is
the one with a real use -- a container that published its SSH port on the
loopback interface is genuinely somewhere else -- and port 22 is refused even
there, because that one is this host's own sshd.

Enforced in five places, because a row can predate a setting: saving a profile,
`session.resolve` (the control every agent tool, the terminal and the canvas go
through), the composer's picker, browsing, and the draft the panels open against
before a chat exists. Check refuses before it opens its socket rather than after.

And the recognition never resolves a name on the request path. `refusal` runs
several times per page render; the first version of this looked names up inline
and the suite went from two minutes to not finishing. Literal forms are decided
from the string, a name is settled where a network call is already expected, and
the answer lives on the row. The gap that leaves is written down rather than
discovered.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/lembas/db/models/agent.py

@@ -53,6 +53,20 @@ class SshProfile(UUIDPrimaryKey, Timestamps, Base):
     port: Mapped[int] = mapped_column(Integer, default=22, nullable=False)
     username: Mapped[str] = mapped_column(String(120), nullable=False)
 
+    # Whether `host` resolved to loopback the last time anybody looked. Written
+    # where a network call is already happening -- saving this connection, and
+    # Check -- and read on every request that asks whether this connection may
+    # be used at all. A column rather than a lookup because that question is
+    # asked several times per page render, and `getaddrinfo` on the request path
+    # makes an agent page wait out a DNS timeout for a host nobody is talking
+    # to. A literal `127.0.0.1` needs none of this and is decided from the
+    # string. See services/agent/hosts.py.
+    #
+    # False on every row an upgrade brings in, which is correct for the literal
+    # case (decided from the string anyway) and optimistic for a *name* until it
+    # is next saved or checked.
+    resolves_here: Mapped[bool] = mapped_column(Boolean, default=False, nullable=False)
+
     auth: Mapped[str] = mapped_column(String(16), default=AUTH_KEY, nullable=False)
     password_encrypted: Mapped[str] = mapped_column(Text, default="")
     private_key_encrypted: Mapped[str] = mapped_column(Text, default="")