diff --git a/docs/observability.md b/docs/observability.md
index 5a3fbea0..5e4f5b01 100644
--- a/docs/observability.md
+++ b/docs/observability.md
@@ -16,8 +16,11 @@ services.hyperhive.otel = {
 };
 ```
 
-`enable` is the single gate. `endpoint` (required when enabled) is where
-telemetry ultimately goes.
+`enable` is the single gate. `endpoint` is where telemetry goes upstream —
+required when enabled *unless* this host runs the swarm's own metrics store
+(`swarm.victoriametrics.enable`), which is a destination in its own right. With
+both, telemetry goes to both. See
+[`swarm/services.md`](swarm/services.md#metrics-victoriametrics--grafana).
 
 **There is exactly one way telemetry leaves a hive: through the collector that
 `enable` starts on the host.** Agents never talk to `endpoint` themselves —
@@ -58,11 +61,16 @@ closed by this design, and nothing here should be read as closing it.
 
 Master switch. When true, all other options below take effect.
 
-### `services.hyperhive.otel.endpoint` — string, required when enabled
+### `services.hyperhive.otel.endpoint` — string, required when enabled unless the swarm store runs here
 
-OTLP collector endpoint URL. Set as `OTEL_EXPORTER_OTLP_ENDPOINT` for every
+Upstream OTLP endpoint URL. Set as `OTEL_EXPORTER_OTLP_ENDPOINT` for every
 agent. Example: `"https://collector.example.com/otel"`.
 
+Leave it empty **only** on a host running `swarm.victoriametrics.enable` — the
+local store is then the destination and the collector writes there instead.
+With neither, `enable` is refused at eval: telemetry with nowhere to go is a
+misconfiguration, not a quiet no-op.
+
 ### `services.hyperhive.otel.protocol` — enum, default `"http/protobuf"`
 
 OTLP wire protocol, passed as `OTEL_EXPORTER_OTLP_PROTOCOL`. Accepted values:
@@ -142,12 +150,16 @@ protects it from other containers, not from the agent itself. As long as the
 direct path stays *selectable*, that hole stays selectable; an option that can
 reintroduce it is a hole with extra steps.
 
-**`endpoint` keeps meaning "where telemetry ultimately goes."** The collector
+**`endpoint` keeps meaning "where telemetry goes upstream."** The collector
 does not redefine it — the agent-facing value is *derived*
 (`http://<bridgeIp>:<collector.port>`), so an existing deployment's `endpoint`
 keeps working unchanged. The bridge port is contributed to `exposeHostPorts`
 automatically; there is nothing to open by hand.
 
+What the collector *added* is a second destination: on a host running the
+swarm's metrics store it writes there too, so `endpoint` is no longer the only
+place telemetry can land — and no longer the only way to have one.
+
 ### `services.hyperhive.otel.collector.port` — port, default `4318`
 
 The OTLP/HTTP port the collector listens on, bound to the bridge IP only.
diff --git a/nix/host-modules/otel.nix b/nix/host-modules/otel.nix
index ca159c84..7d67d5aa 100644
--- a/nix/host-modules/otel.nix
+++ b/nix/host-modules/otel.nix
@@ -36,8 +36,15 @@
       default = "";
       example = "https://collector.example.com/otel";
       description = ''
-        OTLP collector endpoint, set as `OTEL_EXPORTER_OTLP_ENDPOINT`
-        for every agent. Required when `enable` is true.
+        Upstream OTLP endpoint, set as `OTEL_EXPORTER_OTLP_ENDPOINT` for
+        every agent.
+
+        Required when `enable` is true, **unless** this host runs the
+        swarm's metrics store
+        ({option}`services.hyperhive.swarm.victoriametrics.enable`) — that
+        store is a destination in its own right, and with both configured
+        telemetry goes to both. With neither, `enable` is refused rather
+        than silently exporting nowhere.
       '';
     };