diff --git a/docs/turn-loop/config.md b/docs/turn-loop/config.md
index 931134d1..044bed95 100644
--- a/docs/turn-loop/config.md
+++ b/docs/turn-loop/config.md
@@ -131,8 +131,8 @@ single-host deploy, but are useful for multi-hive or custom-network
 setups.
 
 ```nix
-hyperhive.forge.url = "http://localhost:3000";   # default
-hyperhive.matrix.url = "http://localhost:8008";  # default
+hyperhive.forge.url = "http://forge.example:3000";  # default: null
+hyperhive.matrix.url = "http://localhost:8008";     # default
 ```
 
 **`hyperhive.forge.url`** — base URL of the Forgejo instance. Used by
@@ -141,7 +141,18 @@ directly from the agent's `forge-token`, so `tea` and `hive-forge`
 work without an interactive auth step. The unit is a no-op when
 `forge-token` is absent. Override when the agent should connect to a
 Forgejo on a different host or port (e.g. a swarm peer's forge).
-Validated: must be an `http://` or `https://` URL or the empty string.
+Validated: must be an `http://` or `https://` URL, or `null`.
+
+**Defaults to `null`, meaning "no forge" — not a guessed address.** A
+loopback default would only ever be correct when the forge shares the
+agent's network namespace, and inside a container `localhost` is the
+agent itself, so the default was a value that built fine and then talked
+to the wrong machine. With `null` the `tea-login` and `forge-avatar-sync`
+units are not generated at all: an absent integration rather than a
+misdirected one. You do not normally set this — hive-c0re renders the
+host's real forge URL into every agent, and refuses to write a meta
+flake without one, so `null` only survives where the agent modules are
+evaluated outside a hive.
 
 **`hyperhive.matrix.url`** — homeserver URL used by
 `hive-matrix-daemon` when connecting via the matrix-sdk. Default