feat(ecc2): persist file activity patch previews

ecc2/src/session/mod.rs

@@ -135,6 +135,7 @@ pub struct FileActivityEntry {
     pub path: String,
     pub summary: String,
     pub diff_preview: Option<String>,
+    pub patch_preview: Option<String>,
     pub timestamp: DateTime<Utc>,
 }
 

ecc2/src/session/store.rs

@@ -761,6 +761,8 @@ impl StateStore {
             action: String,
             #[serde(default)]
             diff_preview: Option<String>,
+            #[serde(default)]
+            patch_preview: Option<String>,
         }
 
         let file = File::open(metrics_path)
@@ -803,6 +805,7 @@ impl StateStore {
                         path,
                         action: infer_file_activity_action(&row.tool_name),
                         diff_preview: None,
+                        patch_preview: None,
                     })
                     .collect()
             } else {
@@ -818,6 +821,7 @@ impl StateStore {
                             action: parse_file_activity_action(&event.action)
                                 .unwrap_or_else(|| infer_file_activity_action(&row.tool_name)),
                             diff_preview: normalize_optional_string(event.diff_preview),
+                            patch_preview: normalize_optional_string(event.patch_preview),
                         })
                     })
                     .collect()
@@ -1599,6 +1603,7 @@ impl StateStore {
                             path,
                             action: infer_file_activity_action(&tool_name),
                             diff_preview: None,
+                            patch_preview: None,
                         })
                     })
                     .collect()
@@ -1611,6 +1616,7 @@ impl StateStore {
                     path: event.path,
                     summary: summary.clone(),
                     diff_preview: event.diff_preview,
+                    patch_preview: event.patch_preview,
                     timestamp: occurred_at,
                 });
                 if events.len() >= limit {
@@ -1629,6 +1635,8 @@ struct PersistedFileEvent {
     action: FileActivityAction,
     #[serde(default, skip_serializing_if = "Option::is_none")]
     diff_preview: Option<String>,
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    patch_preview: Option<String>,
 }
 
 fn parse_persisted_file_events(value: &str) -> Option<Vec<PersistedFileEvent>> {
@@ -1644,6 +1652,7 @@ fn parse_persisted_file_events(value: &str) -> Option<Vec<PersistedFileEvent>> {
                 path,
                 action: event.action,
                 diff_preview: normalize_optional_string(event.diff_preview),
+                patch_preview: normalize_optional_string(event.patch_preview),
             })
         })
         .collect();
@@ -1959,7 +1968,7 @@ mod tests {
     }
 
     #[test]
-    fn list_file_activity_preserves_diff_previews() -> Result<()> {
+    fn list_file_activity_preserves_diff_and_patch_previews() -> Result<()> {
         let tempdir = TestDir::new("store-file-activity-diffs")?;
         let db = StateStore::open(&tempdir.path().join("state.db"))?;
         let now = Utc::now();
@@ -1984,7 +1993,7 @@ mod tests {
         fs::write(
             &metrics_path,
             concat!(
-                "{\"id\":\"evt-1\",\"session_id\":\"session-1\",\"tool_name\":\"Edit\",\"input_summary\":\"Edit src/config.ts\",\"output_summary\":\"updated config\",\"file_paths\":[\"src/config.ts\"],\"file_events\":[{\"path\":\"src/config.ts\",\"action\":\"modify\",\"diff_preview\":\"API_URL=http://localhost:3000 -> API_URL=https://api.example.com\"}],\"timestamp\":\"2026-04-09T00:00:00Z\"}\n"
+                "{\"id\":\"evt-1\",\"session_id\":\"session-1\",\"tool_name\":\"Edit\",\"input_summary\":\"Edit src/config.ts\",\"output_summary\":\"updated config\",\"file_paths\":[\"src/config.ts\"],\"file_events\":[{\"path\":\"src/config.ts\",\"action\":\"modify\",\"diff_preview\":\"API_URL=http://localhost:3000 -> API_URL=https://api.example.com\",\"patch_preview\":\"@@\\n- API_URL=http://localhost:3000\\n+ API_URL=https://api.example.com\"}],\"timestamp\":\"2026-04-09T00:00:00Z\"}\n"
             ),
         )?;
 
@@ -1998,6 +2007,10 @@ mod tests {
             activity[0].diff_preview.as_deref(),
             Some("API_URL=http://localhost:3000 -> API_URL=https://api.example.com")
         );
+        assert_eq!(
+            activity[0].patch_preview.as_deref(),
+            Some("@@\n- API_URL=http://localhost:3000\n+ API_URL=https://api.example.com")
+        );
 
         Ok(())
     }

ecc2/src/tui/dashboard.rs

@@ -34,6 +34,7 @@ const PANE_RESIZE_STEP_PERCENT: u16 = 5;
 const MAX_LOG_ENTRIES: u64 = 12;
 const MAX_DIFF_PREVIEW_LINES: usize = 6;
 const MAX_DIFF_PATCH_LINES: usize = 80;
+const MAX_FILE_ACTIVITY_PATCH_LINES: usize = 3;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 struct WorktreeDiffColumns {
@@ -203,6 +204,7 @@ struct TimelineEvent {
     session_id: String,
     event_type: TimelineEventType,
     summary: String,
+    detail_lines: Vec<String>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -3410,19 +3412,26 @@ impl Dashboard {
             .into_iter()
             .filter(|event| self.timeline_event_filter.matches(event.event_type))
             .filter(|event| self.output_time_filter.matches_timestamp(event.occurred_at))
-            .map(|event| {
+            .flat_map(|event| {
                 let prefix = if show_session_label {
                     format!("{} ", format_session_id(&event.session_id))
                 } else {
                     String::new()
                 };
-                Line::from(format!(
+                let mut lines = vec![Line::from(format!(
                     "[{}] {}{:<11} {}",
                     event.occurred_at.format("%H:%M:%S"),
                     prefix,
                     event.event_type.label(),
                     event.summary
-                ))
+                ))];
+                lines.extend(
+                    event
+                        .detail_lines
+                        .into_iter()
+                        .map(|line| Line::from(format!("               {}", line))),
+                );
+                lines
             })
             .collect()
     }
@@ -3459,6 +3468,7 @@ impl Dashboard {
                 session.agent_type,
                 truncate_for_dashboard(&session.task, 64)
             ),
+            detail_lines: Vec::new(),
         }];
 
         if session.updated_at > session.created_at {
@@ -3467,6 +3477,7 @@ impl Dashboard {
                 session_id: session.id.clone(),
                 event_type: TimelineEventType::Lifecycle,
                 summary: format!("state {} | updated session metadata", session.state),
+                detail_lines: Vec::new(),
             });
         }
 
@@ -3479,6 +3490,7 @@ impl Dashboard {
                     "attached worktree {} from {}",
                     worktree.branch, worktree.base_branch
                 ),
+                detail_lines: Vec::new(),
             });
         }
 
@@ -3492,6 +3504,7 @@ impl Dashboard {
                 session_id: session.id.clone(),
                 event_type: TimelineEventType::FileChange,
                 summary: format!("files touched {}", session.metrics.files_changed),
+                detail_lines: Vec::new(),
             });
         } else {
             events.extend(file_activity.into_iter().map(|entry| TimelineEvent {
@@ -3499,6 +3512,7 @@ impl Dashboard {
                 session_id: session.id.clone(),
                 event_type: TimelineEventType::FileChange,
                 summary: file_activity_summary(&entry),
+                detail_lines: file_activity_patch_lines(&entry, MAX_FILE_ACTIVITY_PATCH_LINES),
             }));
         }
 
@@ -3525,6 +3539,7 @@ impl Dashboard {
                         64
                     )
                 ),
+                detail_lines: Vec::new(),
             }
         }));
 
@@ -3544,6 +3559,7 @@ impl Dashboard {
                     entry.duration_ms,
                     truncate_for_dashboard(&entry.input_summary, 56)
                 ),
+                detail_lines: Vec::new(),
             })
         }));
         events
@@ -4148,6 +4164,9 @@ impl Dashboard {
                         self.short_timestamp(&entry.timestamp.to_rfc3339()),
                         file_activity_summary(&entry)
                     ));
+                    for detail in file_activity_patch_lines(&entry, 2) {
+                        lines.push(format!("  {}", detail));
+                    }
                 }
             }
             lines.push(format!(
@@ -5412,6 +5431,22 @@ fn file_activity_summary(entry: &FileActivityEntry) -> String {
     summary
 }
 
+fn file_activity_patch_lines(entry: &FileActivityEntry, max_lines: usize) -> Vec<String> {
+    entry
+        .patch_preview
+        .as_deref()
+        .map(|patch| {
+            patch
+                .lines()
+                .map(str::trim)
+                .filter(|line| !line.is_empty() && *line != "@@" && *line != "+" && *line != "-")
+                .take(max_lines)
+                .map(|line| truncate_for_dashboard(line, 72))
+                .collect()
+        })
+        .unwrap_or_default()
+}
+
 fn file_activity_verb(action: crate::session::FileActivityAction) -> &'static str {
     match action {
         crate::session::FileActivityAction::Read => "read",
@@ -6092,7 +6127,7 @@ mod tests {
             &metrics_path,
             concat!(
                 "{\"id\":\"evt-1\",\"session_id\":\"focus-12345678\",\"tool_name\":\"Read\",\"input_summary\":\"Read src/lib.rs\",\"output_summary\":\"ok\",\"file_paths\":[\"src/lib.rs\"],\"timestamp\":\"2026-04-09T00:00:00Z\"}\n",
-                "{\"id\":\"evt-2\",\"session_id\":\"focus-12345678\",\"tool_name\":\"Write\",\"input_summary\":\"Write README.md\",\"output_summary\":\"updated readme\",\"file_paths\":[\"README.md\"],\"file_events\":[{\"path\":\"README.md\",\"action\":\"create\",\"diff_preview\":\"+ # ECC 2.0\"}],\"timestamp\":\"2026-04-09T00:01:00Z\"}\n"
+                "{\"id\":\"evt-2\",\"session_id\":\"focus-12345678\",\"tool_name\":\"Write\",\"input_summary\":\"Write README.md\",\"output_summary\":\"updated readme\",\"file_paths\":[\"README.md\"],\"file_events\":[{\"path\":\"README.md\",\"action\":\"create\",\"diff_preview\":\"+ # ECC 2.0\",\"patch_preview\":\"+ # ECC 2.0\\n+ \\n+ A richer dashboard\"}],\"timestamp\":\"2026-04-09T00:01:00Z\"}\n"
             ),
         )?;
         dashboard.db.sync_tool_activity_metrics(&metrics_path)?;
@@ -6103,12 +6138,14 @@ mod tests {
         assert!(rendered.contains("read src/lib.rs"));
         assert!(rendered.contains("create README.md"));
         assert!(rendered.contains("+ # ECC 2.0"));
+        assert!(rendered.contains("+ A richer dashboard"));
         assert!(!rendered.contains("files touched 2"));
 
         let metrics_text = dashboard.selected_session_metrics_text();
         assert!(metrics_text.contains("Recent file activity"));
         assert!(metrics_text.contains("create README.md"));
         assert!(metrics_text.contains("+ # ECC 2.0"));
+        assert!(metrics_text.contains("+ A richer dashboard"));
         assert!(metrics_text.contains("read src/lib.rs"));
 
         let _ = fs::remove_dir_all(root);

scripts/hooks/session-activity-tracker.js

@@ -62,7 +62,7 @@ function pushPathCandidate(paths, value) {
   }
 }
 
-function pushFileEvent(events, value, action, diffPreview) {
+function pushFileEvent(events, value, action, diffPreview, patchPreview) {
   const candidate = String(value || '').trim();
   if (!candidate) {
     return;
@@ -73,15 +73,22 @@ function pushFileEvent(events, value, action, diffPreview) {
   const normalizedDiffPreview = typeof diffPreview === 'string' && diffPreview.trim()
     ? diffPreview.trim()
     : undefined;
+  const normalizedPatchPreview = typeof patchPreview === 'string' && patchPreview.trim()
+    ? patchPreview.trim()
+    : undefined;
   if (!events.some(event =>
     event.path === candidate
       && event.action === action
       && (event.diff_preview || undefined) === normalizedDiffPreview
+      && (event.patch_preview || undefined) === normalizedPatchPreview
   )) {
     const event = { path: candidate, action };
     if (normalizedDiffPreview) {
       event.diff_preview = normalizedDiffPreview;
     }
+    if (normalizedPatchPreview) {
+      event.patch_preview = normalizedPatchPreview;
+    }
     events.push(event);
   }
 }
@@ -93,6 +100,19 @@ function sanitizeDiffText(value, maxLength = 96) {
   return truncateSummary(value, maxLength);
 }
 
+function sanitizePatchLines(value, maxLines = 4, maxLineLength = 120) {
+  if (typeof value !== 'string' || !value.trim()) {
+    return [];
+  }
+
+  return stripAnsi(redactSecrets(value))
+    .split(/\r?\n/)
+    .map(line => line.trim())
+    .filter(Boolean)
+    .slice(0, maxLines)
+    .map(line => line.length <= maxLineLength ? line : `${line.slice(0, maxLineLength - 3)}...`);
+}
+
 function buildReplacementPreview(oldValue, newValue) {
   const before = sanitizeDiffText(oldValue);
   const after = sanitizeDiffText(newValue);
@@ -116,6 +136,31 @@ function buildCreationPreview(content) {
   return `+ ${normalized}`;
 }
 
+function buildPatchPreviewFromReplacement(oldValue, newValue) {
+  const beforeLines = sanitizePatchLines(oldValue);
+  const afterLines = sanitizePatchLines(newValue);
+  if (beforeLines.length === 0 && afterLines.length === 0) {
+    return undefined;
+  }
+
+  const lines = ['@@'];
+  for (const line of beforeLines) {
+    lines.push(`- ${line}`);
+  }
+  for (const line of afterLines) {
+    lines.push(`+ ${line}`);
+  }
+  return lines.join('\n');
+}
+
+function buildPatchPreviewFromContent(content, prefix) {
+  const lines = sanitizePatchLines(content);
+  if (lines.length === 0) {
+    return undefined;
+  }
+  return lines.map(line => `${prefix} ${line}`).join('\n');
+}
+
 function inferDefaultFileAction(toolName) {
   const normalized = String(toolName || '').trim().toLowerCase();
   if (normalized.includes('read')) {
@@ -204,6 +249,26 @@ function fileEventDiffPreview(toolName, value, action) {
   return undefined;
 }
 
+function fileEventPatchPreview(value, action) {
+  if (!value || typeof value !== 'object' || Array.isArray(value)) {
+    return undefined;
+  }
+
+  if (typeof value.old_string === 'string' || typeof value.new_string === 'string') {
+    return buildPatchPreviewFromReplacement(value.old_string, value.new_string);
+  }
+
+  if (action === 'create') {
+    return buildPatchPreviewFromContent(value.content || value.file_text || value.text, '+');
+  }
+
+  if (action === 'delete') {
+    return buildPatchPreviewFromContent(value.content || value.old_string || value.file_text, '-');
+  }
+
+  return undefined;
+}
+
 function collectFileEvents(toolName, value, events, key = null, parentValue = null) {
   if (!value) {
     return;
@@ -219,7 +284,13 @@ function collectFileEvents(toolName, value, events, key = null, parentValue = nu
   if (typeof value === 'string') {
     if (key && FILE_PATH_KEYS.has(key)) {
       const action = actionForFileKey(toolName, key);
-      pushFileEvent(events, value, action, fileEventDiffPreview(toolName, parentValue, action));
+      pushFileEvent(
+        events,
+        value,
+        action,
+        fileEventDiffPreview(toolName, parentValue, action),
+        fileEventPatchPreview(parentValue, action)
+      );
     }
     return;
   }

tests/hooks/session-activity-tracker.test.js

@@ -155,6 +155,7 @@ function runTests() {
         path: 'src/config.ts',
         action: 'modify',
         diff_preview: 'API_URL=http://localhost:3000 -> API_URL=https://api.example.com',
+        patch_preview: '@@\n- API_URL=http://localhost:3000\n+ API_URL=https://api.example.com',
       },
     ]);
 
@@ -196,11 +197,13 @@ function runTests() {
         path: 'src/a.ts',
         action: 'modify',
         diff_preview: 'const a = 1; -> const a = 2;',
+        patch_preview: '@@\n- const a = 1;\n+ const a = 2;',
       },
       {
         path: 'src/b.ts',
         action: 'modify',
         diff_preview: 'old name -> new name',
+        patch_preview: '@@\n- old name\n+ new name',
       },
     ]);