diff --git a/server/src/bridge/types.rs b/server/src/bridge/types.rs
index 7395e0505..5eb9272c7 100644
--- a/server/src/bridge/types.rs
+++ b/server/src/bridge/types.rs
@@ -32,7 +32,7 @@ pub const PROTOCOL_VERSION: u8 = 10;
 /// Future fields: ambient sound events, HUD state (D-020 expansion).
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct ObserverSnapshot {
-    /// Protocol version for forward compatibility. Current: 9.
+    /// Protocol version for forward compatibility. Current: 10.
     pub version: u8,
     /// Simulation tick when this snapshot was produced
     pub tick: u64,
diff --git a/server/src/perception/anomaly.rs b/server/src/perception/anomaly.rs
index bea13b139..415e05fb7 100644
--- a/server/src/perception/anomaly.rs
+++ b/server/src/perception/anomaly.rs
@@ -40,6 +40,7 @@ pub fn clear_anomaly_markers(mut commands: Commands, markers: Query<Entity, With
 /// OR KG.state == Contradicted. Skips the player entity.
 ///
 /// System ordering: after clear_anomaly_markers, before emit_observation_events.
+#[tracing::instrument(level = "debug", skip_all)]
 pub fn detect_anomalies(
     mut commands: Commands,
     observer_query: Query<(Entity, &KnowledgeGraph), With<PlayerCharacter>>,
diff --git a/server/src/perception/cognitive_delay.rs b/server/src/perception/cognitive_delay.rs
index 14517ca7b..faaba4fc9 100644
--- a/server/src/perception/cognitive_delay.rs
+++ b/server/src/perception/cognitive_delay.rs
@@ -148,6 +148,7 @@ impl CognitiveDelay {
 /// Expired recognitions are converted to DirectObservation KnowledgeEvents.
 ///
 /// System ordering: after emit_observation_events, before process_knowledge_events.
+#[tracing::instrument(level = "debug", skip_all)]
 pub fn process_cognitive_delay(
     time: Res<SimulationTime>,
     mut query: Query<(Entity, &mut CognitiveDelay)>,
diff --git a/server/src/perception/observer/mod.rs b/server/src/perception/observer/mod.rs
index 55c9d7bf8..b41e652e4 100644
--- a/server/src/perception/observer/mod.rs
+++ b/server/src/perception/observer/mod.rs
@@ -29,6 +29,7 @@ use crate::simulation::time::SimulationTime;
 /// Stage 1 of the observer pipeline: FOV + vision cone → VisibilityGeometry.
 ///
 /// System ordering: after validate_movement, before compute_observer_snapshot.
+#[tracing::instrument(level = "debug", skip_all)]
 pub fn compute_visibility_geometry(
     walkability: Res<WalkabilityMap>,
     mode: Res<ActivePerceptionMode>,
@@ -52,6 +53,7 @@ pub fn compute_visibility_geometry(
 ///
 /// System ordering: after compute_visibility_geometry + compute_nearby_interactions,
 /// before advance_tick.
+#[tracing::instrument(level = "debug", skip_all)]
 #[allow(clippy::type_complexity, clippy::too_many_arguments)]
 pub fn compute_observer_snapshot(
     time: Res<SimulationTime>,
diff --git a/server/src/simulation/dialogue.rs b/server/src/simulation/dialogue.rs
index c9b9366d3..ff3603fe1 100644
--- a/server/src/simulation/dialogue.rs
+++ b/server/src/simulation/dialogue.rs
@@ -337,6 +337,7 @@ pub fn select_dialogue_line<'a>(
 /// line to DialogueResponseBuffer.
 ///
 /// System ordering: after process_player_input, before compute_observer_snapshot.
+#[tracing::instrument(level = "debug", skip_all)]
 #[allow(clippy::type_complexity, clippy::too_many_arguments)]
 pub fn process_talk_interaction(
     mut commands: Commands,
diff --git a/server/src/simulation/interaction.rs b/server/src/simulation/interaction.rs
index 5c0025256..1116c8ca7 100644
--- a/server/src/simulation/interaction.rs
+++ b/server/src/simulation/interaction.rs
@@ -164,6 +164,7 @@ impl ObjectType {
 /// priority adjustment (e.g. POI -> Observe first) is applied by the observer
 /// system after taking the buffer. This keeps the simulation phase free of
 /// knowledge graph dependencies (D-010 phase boundary).
+#[tracing::instrument(level = "debug", skip_all)]
 #[allow(clippy::type_complexity)]
 pub fn compute_nearby_interactions(
     mut player_query: Query<
diff --git a/server/src/simulation/movement.rs b/server/src/simulation/movement.rs
index a0c38aa68..4bfa456f5 100644
--- a/server/src/simulation/movement.rs
+++ b/server/src/simulation/movement.rs
@@ -273,6 +273,7 @@ pub struct MoveIntent {
 /// entities without intents, then resolve movers in order — first valid claim
 /// to a layer slot wins.
 /// Always removes MoveIntent component after processing.
+#[tracing::instrument(level = "debug", skip_all)]
 pub fn validate_movement(
     mut commands: Commands,
     walkability: Option<Res<WalkabilityMap>>,
diff --git a/server/src/simulation/path_follow.rs b/server/src/simulation/path_follow.rs
index 64a11c3fe..560110540 100644
--- a/server/src/simulation/path_follow.rs
+++ b/server/src/simulation/path_follow.rs
@@ -48,6 +48,7 @@ impl MovementSpeed {
 
 /// System: NPC entities with ComputedPath advance along their path.
 /// Creates MoveIntent for the next step. Removes ComputedPath when complete.
+#[tracing::instrument(level = "debug", skip_all)]
 pub fn follow_paths(
     mut commands: Commands,
     mut query: Query<(Entity, &mut ComputedPath, Option<&mut MovementSpeed>), With<Npc>>,
diff --git a/server/src/simulation/pathfinding.rs b/server/src/simulation/pathfinding.rs
index cc1b1a365..51cd71ab6 100644
--- a/server/src/simulation/pathfinding.rs
+++ b/server/src/simulation/pathfinding.rs
@@ -58,6 +58,7 @@ pub struct PathBlocked;
 /// Cardinal-only is a deliberate v0.1 simplification: diagonal movement
 /// would require √2 cost handling and diagonal wall-clipping checks.
 /// Removes PathRequest and inserts ComputedPath or PathBlocked.
+#[tracing::instrument(level = "debug", skip_all)]
 pub fn compute_paths(
     mut commands: Commands,
     walkability: Option<Res<WalkabilityMap>>,