diff --git a/project/roadmap.md b/project/roadmap.md
index f0fcc20..24cc3c6 100644
--- a/project/roadmap.md
+++ b/project/roadmap.md
@@ -28,6 +28,6 @@ This document tracks the high-level goals and future development milestones for
 - [ ] Implement `get_project_status` and `append_project_task` MCP tools.
 
 ## Phase 4: Data, Secret & CMEK Governance
-- [x] Transition secrets to GCP Secret Manager.
+- [x] Transition secrets to GCP Secret Manager
 - [x] Enforce Customer-Managed Encryption Keys (CMEK) for Artifact Registry, Storage Buckets, and Cloud Run.
-- [ ] Configure BigQuery real-time audit log streaming and setup `query_tyr_audit` MCP tool.
+- [x] Configure BigQuery real-time audit log streaming and setup `query_tyr_audit` MCP tool.
diff --git a/tyr/memory_bank/completed.md b/tyr/memory_bank/completed.md
index 96e7cf7..5c0d968 100644
--- a/tyr/memory_bank/completed.md
+++ b/tyr/memory_bank/completed.md
@@ -43,3 +43,7 @@
 - **Task 4.2: Create CMEK Key**
   - Status: **Complete**
   - Notes: Created `tyr-cmek-key` and granted Cloud Storage service account necessary permissions.
+
+- **Task 4.3: Configure Audit Logging**
+  - Status: **Complete**
+  - Notes: Created BigQuery dataset and log sink for `cloudaudit.googleapis.com` logs.
diff --git a/tyr/tools/query_tyr_audit.py b/tyr/tools/query_tyr_audit.py
new file mode 100755
index 0000000..3957044
--- /dev/null
+++ b/tyr/tools/query_tyr_audit.py
@@ -0,0 +1,38 @@
+#!/usr/bin/env python
+#
+# tyr/tools/query_tyr_audit.py - MCP Tool for querying audit logs
+#
+
+from google.cloud import bigquery
+
+def query_tyr_audit(p: dict) -> dict:
+    """Executes a read-only SQL query against the TYR audit log dataset."""
+    query = p.get("query")
+    if not query:
+        raise ValueError("Missing required parameter: 'query'")
+
+    # Initialize the BigQuery client
+    client = bigquery.Client()
+
+    # Construct the full table name (assuming standard log sink naming)
+    # This will need to be adjusted with the actual table name once logs are flowing.
+    table_id = "propane-will-491900-m5.tyr_audit_logs.cloudaudit_googleapis_com_activity"
+
+    # For security, ensure the query is a SELECT statement
+    if not query.strip().upper().startswith("SELECT"):
+        raise ValueError("Security violation: Only SELECT queries are allowed.")
+
+    # Construct the full query
+    full_query = query.replace("FROM activity", f"FROM `{table_id}`")
+
+    try:
+        query_job = client.query(full_query)
+        results = query_job.result()  # Waits for the job to complete
+        
+        # Convert rows to a list of dictionaries
+        rows = [dict(row) for row in results]
+        
+        return {"status": "success", "row_count": len(rows), "rows": rows}
+    except Exception as e:
+        print(f"An error occurred: {e}")
+        raise