diff --git a/webui/src/components/pages/dashboard/Dashboard.tsx b/webui/src/components/pages/dashboard/Dashboard.tsx
index b97ba9d..053ffe7 100644
--- a/webui/src/components/pages/dashboard/Dashboard.tsx
+++ b/webui/src/components/pages/dashboard/Dashboard.tsx
@@ -67,8 +67,55 @@ export function Dashboard() {
           {/* Two equal columns: CryoEM Facilities and SmartEM Application */}
           <Box sx={{ display: 'flex', flexDirection: 'row', flex: 1, gap: 3 }}>
             {/* CryoEM Facilities */}
-            <Box sx={{ flex: 1, display: 'flex', flexDirection: 'column', gap: 1 }}>
+            <Box sx={{ flex: 1, display: 'flex', flexDirection: 'column', gap: 2.5 }}>
               <MicroscopeGrid />
+              <Box
+                data-connection-id="dls-keycloak"
+                sx={{ display: 'flex', flexDirection: 'column' }}
+              >
+                <SystemComponentContainer heading="DLS Keycloak">
+                  <Box sx={{ ...itemBoxSx, display: 'flex', flexDirection: 'column', gap: 0.5 }}>
+                    <Typography variant="caption" sx={{ color: '#333', fontWeight: 500 }}>
+                      Realm: dls
+                    </Typography>
+                    <Typography
+                      variant="caption"
+                      component="div"
+                      sx={{ color: '#555', fontSize: '0.65rem', fontFamily: 'monospace' }}
+                    >
+                      Production:{' '}
+                      <Link href="https://identity.diamond.ac.uk" target="_blank" rel="noopener">
+                        https://identity.diamond.ac.uk
+                      </Link>
+                      <br />
+                      Test:{' '}
+                      <Link
+                        href="https://identity-test.diamond.ac.uk"
+                        target="_blank"
+                        rel="noopener"
+                      >
+                        https://identity-test.diamond.ac.uk
+                      </Link>
+                    </Typography>
+
+                    <Typography variant="caption" sx={{ color: '#333', fontWeight: 500, mt: 1 }}>
+                      Clients
+                    </Typography>
+                    <Typography
+                      variant="caption"
+                      component="div"
+                      sx={{ color: '#555', fontSize: '0.65rem', fontFamily: 'monospace' }}
+                    >
+                      - SmartEM_User (public, OIDC authorization code + PKCE)
+                      <br />- SmartEM_Agent (confidential, OAuth 2.0 client_credentials)
+                      <br />
+                      Backend validates Bearer tokens against JWKS.
+                      <br />
+                      See ADR 0018 for the agent auth design.
+                    </Typography>
+                  </Box>
+                </SystemComponentContainer>
+              </Box>
             </Box>
 
             {/* SmartEM Application */}
diff --git a/webui/src/components/pages/dashboard/components/ConnectionsOverlay.tsx b/webui/src/components/pages/dashboard/components/ConnectionsOverlay.tsx
index 0ee736f..a4f963d 100644
--- a/webui/src/components/pages/dashboard/components/ConnectionsOverlay.tsx
+++ b/webui/src/components/pages/dashboard/components/ConnectionsOverlay.tsx
@@ -241,6 +241,7 @@ export function ConnectionsOverlay({ connections, containerRef }: ConnectionsOve
               d={pathD}
               stroke={conn.color}
               strokeWidth={2}
+              strokeDasharray={conn.strokeDasharray}
               fill="none"
               style={{ pointerEvents: 'none' }}
             />
diff --git a/webui/src/components/pages/dashboard/components/MicroscopeGrid.tsx b/webui/src/components/pages/dashboard/components/MicroscopeGrid.tsx
index b29c7db..650f2fc 100644
--- a/webui/src/components/pages/dashboard/components/MicroscopeGrid.tsx
+++ b/webui/src/components/pages/dashboard/components/MicroscopeGrid.tsx
@@ -16,7 +16,6 @@ export function MicroscopeGrid() {
         display: 'flex',
         flexDirection: 'column',
         gap: 7,
-        flex: 1,
       }}
     >
       {detailed.map((instrument) => (
diff --git a/webui/src/components/pages/dashboard/components/connectionConfig.ts b/webui/src/components/pages/dashboard/components/connectionConfig.ts
index 9220335..d88e8a4 100644
--- a/webui/src/components/pages/dashboard/components/connectionConfig.ts
+++ b/webui/src/components/pages/dashboard/components/connectionConfig.ts
@@ -10,6 +10,9 @@ export interface Connection {
   sourceDotOffset?: number // Offset along the edge for source dot (positive = right/down)
   targetDotOffset?: number // Offset along the edge for target dot (positive = right/down)
   arrow?: 'source' | 'target' | 'both' | 'none' // Arrow direction (default: 'none')
+  // Trust/identity edges (e.g. auth flows) use a dashed stroke so they read
+  // as a different kind of edge from data/RPC paths.
+  strokeDasharray?: string
 }
 
 // Color palette for connections
@@ -21,6 +24,7 @@ const colors = {
   purple: '#9c27b0', // C3: Agent -> Athena API (microscope control)
   teal: '#009688', // C4: ARIA Connector flows
   pink: '#e91e63', // C5: Web UI -> Backend API
+  gold: '#b8860b', // Auth: Keycloak trust/identity edges (rendered dashed)
 }
 
 export const dashboardConnections: Connection[] = [
@@ -125,4 +129,52 @@ export const dashboardConnections: Connection[] = [
     curveOffset: 90, // More curvature for pink connection
     arrow: 'source', // Arrow pointing to Web UI (data flows from API to UI)
   },
+  // C6: Auth — SmartEM Web UI -> DLS Keycloak (OIDC authorization code + PKCE)
+  // Keycloak sits in the left column under the microscope grid; UI is in the
+  // middle column, so the edge runs leftward.
+  {
+    id: 'webui-to-keycloak',
+    sourceId: 'smartem-webui',
+    targetId: 'dls-keycloak',
+    sourceAnchor: 'left',
+    targetAnchor: 'right',
+    color: colors.gold,
+    tooltip:
+      'SmartEM Web UI authenticates users against DLS Keycloak via OIDC authorization code flow with PKCE (SmartEM_User client)',
+    strokeDasharray: '6 4',
+    sourceDotOffset: -10,
+    arrow: 'target',
+  },
+  // C6: Auth — SmartEM Agent -> DLS Keycloak (client_credentials grant)
+  // Both live in the left column with Keycloak below the microscope grid.
+  // Endpoints are nudged right of column-centre so the line runs alongside
+  // the "+N more microscopes" stack without overlapping its centred text+icon.
+  {
+    id: 'agent-to-keycloak',
+    sourceId: 'smartem-agent',
+    targetId: 'dls-keycloak',
+    sourceAnchor: 'bottom',
+    targetAnchor: 'top',
+    color: colors.gold,
+    tooltip:
+      'SmartEM Agent obtains service-account tokens from DLS Keycloak via OAuth 2.0 client_credentials grant (SmartEM_Agent client). See ADR 0018.',
+    strokeDasharray: '6 4',
+    sourceDotOffset: 60,
+    targetDotOffset: 130,
+    arrow: 'target',
+  },
+  // C6: Auth — SmartEM Backend API -> DLS Keycloak (JWKS for Bearer-token validation)
+  {
+    id: 'backend-to-keycloak',
+    sourceId: 'smartem-backend-api',
+    targetId: 'dls-keycloak',
+    sourceAnchor: 'left',
+    targetAnchor: 'right',
+    color: colors.gold,
+    tooltip:
+      'SmartEM Backend validates incoming Bearer tokens (from Web UI and Agent) against the DLS Keycloak JWKS endpoint',
+    strokeDasharray: '6 4',
+    sourceDotOffset: -10,
+    arrow: 'target',
+  },
 ]