diff --git a/Cargo.lock b/Cargo.lock
index cbc5687..3b60d22 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -139,8 +139,8 @@ dependencies = [
 
 [[package]]
 name = "echo-system-types"
-version = "0.2.0"
-source = "git+https://github.com/dnacenta/echo-system-types?tag=v0.2.0#acbadc847e4af646025d67b968330c07083a0d96"
+version = "0.3.0"
+source = "git+https://github.com/dnacenta/echo-system-types?tag=v0.3.0#ad901031f50fe6f0bef5a9476bbc97a778d00124"
 dependencies = [
  "serde",
  "serde_json",
@@ -505,7 +505,7 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
 [[package]]
 name = "vigil-echo"
-version = "0.2.0"
+version = "0.3.0"
 dependencies = [
  "clap",
  "dirs",
diff --git a/Cargo.toml b/Cargo.toml
index 5d91968..e35963a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "vigil-echo"
-version = "0.2.0"
+version = "0.3.0"
 edition = "2021"
 description = "Metacognitive monitoring for AI self-evolution"
 license = "AGPL-3.0-only"
@@ -10,7 +10,7 @@ categories = ["command-line-utilities"]
 authors = ["dnacenta"]
 
 [dependencies]
-echo-system-types = { git = "https://github.com/dnacenta/echo-system-types", tag = "v0.2.0" }
+echo-system-types = { git = "https://github.com/dnacenta/echo-system-types", tag = "v0.3.0" }
 clap = { version = "4", features = ["derive"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
diff --git a/src/runtime.rs b/src/runtime.rs
index f43a49c..b5ffce2 100644
--- a/src/runtime.rs
+++ b/src/runtime.rs
@@ -403,6 +403,148 @@ where
     calc_float_trend(frames, |f| if extractor(f) { 1.0 } else { 0.0 })
 }
 
+// ---------------------------------------------------------------------------
+// Trait implementation: CognitiveMonitor
+// ---------------------------------------------------------------------------
+
+use echo_system_types::monitoring as shared;
+
+/// Concrete implementation of the CognitiveMonitor trait.
+///
+/// pulse-null core creates this and stores it as `Arc<dyn CognitiveMonitor>`.
+/// All existing functions are preserved for standalone CLI use.
+pub struct VigilMonitor;
+
+impl VigilMonitor {
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Default for VigilMonitor {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+// --- Internal ↔ Shared type conversions ---
+
+fn shared_status(s: &CognitiveStatus) -> shared::CognitiveStatus {
+    match s {
+        CognitiveStatus::Healthy => shared::CognitiveStatus::Healthy,
+        CognitiveStatus::Watch => shared::CognitiveStatus::Watch,
+        CognitiveStatus::Concern => shared::CognitiveStatus::Concern,
+        CognitiveStatus::Alert => shared::CognitiveStatus::Alert,
+    }
+}
+
+fn shared_trend(t: &Trend) -> shared::Trend {
+    match t {
+        Trend::Improving => shared::Trend::Improving,
+        Trend::Stable => shared::Trend::Stable,
+        Trend::Declining => shared::Trend::Declining,
+    }
+}
+
+fn shared_cognitive_health(h: &CognitiveHealth) -> shared::CognitiveHealth {
+    shared::CognitiveHealth {
+        status: shared_status(&h.status),
+        vocabulary_trend: shared_trend(&h.vocabulary_trend),
+        question_trend: shared_trend(&h.question_trend),
+        evidence_trend: shared_trend(&h.evidence_trend),
+        progress_trend: shared_trend(&h.progress_trend),
+        suggestions: h.suggestions.clone(),
+        sufficient_data: h.sufficient_data,
+    }
+}
+
+fn internal_cognitive_health(h: &shared::CognitiveHealth) -> CognitiveHealth {
+    CognitiveHealth {
+        status: match h.status {
+            shared::CognitiveStatus::Healthy => CognitiveStatus::Healthy,
+            shared::CognitiveStatus::Watch => CognitiveStatus::Watch,
+            shared::CognitiveStatus::Concern => CognitiveStatus::Concern,
+            shared::CognitiveStatus::Alert => CognitiveStatus::Alert,
+        },
+        vocabulary_trend: match h.vocabulary_trend {
+            shared::Trend::Improving => Trend::Improving,
+            shared::Trend::Stable => Trend::Stable,
+            shared::Trend::Declining => Trend::Declining,
+        },
+        question_trend: match h.question_trend {
+            shared::Trend::Improving => Trend::Improving,
+            shared::Trend::Stable => Trend::Stable,
+            shared::Trend::Declining => Trend::Declining,
+        },
+        evidence_trend: match h.evidence_trend {
+            shared::Trend::Improving => Trend::Improving,
+            shared::Trend::Stable => Trend::Stable,
+            shared::Trend::Declining => Trend::Declining,
+        },
+        progress_trend: match h.progress_trend {
+            shared::Trend::Improving => Trend::Improving,
+            shared::Trend::Stable => Trend::Stable,
+            shared::Trend::Declining => Trend::Declining,
+        },
+        suggestions: h.suggestions.clone(),
+        sufficient_data: h.sufficient_data,
+    }
+}
+
+fn shared_signal_frame(f: &SignalFrame) -> shared::SignalFrame {
+    shared::SignalFrame {
+        timestamp: f.timestamp.clone(),
+        task_id: f.task_id.clone(),
+        vocabulary_diversity: f.vocabulary_diversity,
+        question_count: f.question_count,
+        evidence_references: f.evidence_references,
+        thought_progress: f.thought_progress,
+    }
+}
+
+fn internal_signal_frame(f: &shared::SignalFrame) -> SignalFrame {
+    SignalFrame {
+        timestamp: f.timestamp.clone(),
+        task_id: f.task_id.clone(),
+        vocabulary_diversity: f.vocabulary_diversity,
+        question_count: f.question_count,
+        evidence_references: f.evidence_references,
+        thought_progress: f.thought_progress,
+    }
+}
+
+impl shared::CognitiveMonitor for VigilMonitor {
+    fn assess(
+        &self,
+        root_dir: &Path,
+        window_size: usize,
+        min_samples: usize,
+    ) -> shared::CognitiveHealth {
+        let health = assess(root_dir, window_size, min_samples);
+        shared_cognitive_health(&health)
+    }
+
+    fn render_for_prompt(&self, health: &shared::CognitiveHealth) -> String {
+        let internal = internal_cognitive_health(health);
+        render(&internal)
+    }
+
+    fn extract(&self, content: &str, task_id: &str) -> shared::SignalFrame {
+        let frame = extract(content, task_id);
+        shared_signal_frame(&frame)
+    }
+
+    fn record(
+        &self,
+        root_dir: &Path,
+        frame: shared::SignalFrame,
+        window_size: usize,
+    ) -> Result<(), Box<dyn std::error::Error>> {
+        let internal = internal_signal_frame(&frame);
+        record(root_dir, internal, window_size)
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Tests
 // ---------------------------------------------------------------------------