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+# GRASP-02: Proactive Sync v3 - Event-Driven Design
+
+## Overview
+
+This document presents v3 of the proactive sync design. Key principles:
+
+1. **Self-subscription as the only mechanism** - No database initialization at startup
+2. **Batch-based pending tracking** - Each batch confirms independently
+3. **Single action type** - AddFilters only, auto-spawn connections
+4. **Three-way state model** - RepoSyncIndex (want) → PendingSyncIndex (in-flight) → RelaySyncIndex (confirmed)
+
+---
+
+## Data Model
+
+### RepoSyncIndex (Source of Truth)
+
+```rust
+/// What we WANT to sync - derived from events received via self-subscription.
+/// Updated immediately when self-subscriber batch fires.
+/// Key: repo addressable ref ("30617:pubkey:identifier")
+pub type RepoSyncIndex = Arc<RwLock<HashMap<String, RepoSyncNeeds>>>;
+
+#[derive(Debug, Clone, Default)]
+pub struct RepoSyncNeeds {
+    /// Relay URLs listed in this repo's 30617 announcement
+    pub relays: HashSet<String>,
+    /// Root event IDs (1617/1618/1619/1621) that reference this repo
+    pub root_events: HashSet<EventId>,
+}
+```
+
+### RelaySyncIndex (Confirmed State + Connection)
+
+```rust
+/// What we've CONFIRMED syncing - includes connection state for integrated lifecycle.
+/// Key: relay URL
+pub type RelaySyncIndex = Arc<RwLock<HashMap<String, RelayState>>>;
+
+/// Connection status for a relay
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ConnectionStatus {
+    /// Not currently connected
+    Disconnected,
+    /// Connection attempt in progress
+    Connecting,
+    /// Successfully connected and subscribed
+    Connected,
+}
+
+/// Complete state for a single relay - combines sync needs with connection lifecycle
+#[derive(Debug)]
+pub struct RelayState {
+    /// Repos we've confirmed syncing from this relay
+    pub repos: HashSet<String>,
+    /// Root events we've confirmed tracking
+    pub root_events: HashSet<EventId>,
+    /// If true, never disconnect this relay
+    pub is_bootstrap: bool,
+    /// Current connection status
+    pub connection_status: ConnectionStatus,
+    /// When we last successfully connected (for since filter on reconnect)
+    pub last_connected: Option<Timestamp>,
+    /// When we disconnected (for 15-minute state retention rule)
+    pub disconnected_at: Option<Timestamp>,
+    /// The active connection (None if disconnected)
+    pub connection: Option<RelayConnection>,
+}
+
+impl RelayState {
+    /// Check if state should be cleared based on 15-minute rule
+    pub fn should_clear_state(&self) -> bool {
+        match self.disconnected_at {
+            Some(disconnected) => {
+                let now = Timestamp::now();
+                now.as_u64().saturating_sub(disconnected.as_u64()) > 900 // 15 minutes
+            }
+            None => false, // Still connected or never connected
+        }
+    }
+    
+    /// Clear repos and root_events (called when reconnect takes > 15 minutes)
+    pub fn clear_sync_state(&mut self) {
+        self.repos.clear();
+        self.root_events.clear();
+    }
+}
+```
+
+### PendingSyncIndex (In-Flight Batches)
+
+```rust
+/// Tracks batches of subscriptions that are in-flight, awaiting EOSE.
+/// Each batch has its own ID and can confirm independently.
+/// Key: relay URL
+pub type PendingSyncIndex = Arc<RwLock<HashMap<String, Vec<PendingBatch>>>>;
+
+#[derive(Debug, Clone)]
+pub struct PendingBatch {
+    /// Unique ID for this batch (for debugging/logging)
+    pub batch_id: u64,
+    /// The items this batch is syncing
+    pub items: PendingItems,
+    /// Subscription IDs that must ALL receive EOSE before confirming
+    pub outstanding_subs: HashSet<SubscriptionId>,
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct PendingItems {
+    pub repos: HashSet<String>,
+    pub root_events: HashSet<EventId>,
+}
+```
+
+---
+
+## State Flow
+
+```mermaid
+flowchart TB
+    subgraph Input
+        SS[SelfSubscriber]
+        OWN[Own Relay]
+    end
+    
+    subgraph RepoSyncIndex - Want
+        RSI[HashMap of Repo to Relays+Events]
+    end
+    
+    subgraph Derived Target
+        DT[derive_relay_targets fn]
+        TGT[Per-relay: repos + events we should sync]
+    end
+    
+    subgraph PendingSyncIndex - In Flight
+        PSI[Vec of PendingBatch per relay]
+    end
+    
+    subgraph RelaySyncIndex - State + Connection
+        RLI[RelayState per relay]
+        CONN[connection: Option of RelayConnection]
+        STATUS[connection_status: Connected/Disconnected/Connecting]
+        REPOS[repos + root_events]
+    end
+    
+    SS -->|subscribe| OWN
+    OWN -->|events| SS
+    SS -->|batch fires| RSI
+    RSI --> DT
+    DT --> TGT
+    TGT -->|diff: target - pending - confirmed| DIFF[Compute new items]
+    PSI --> DIFF
+    RLI --> DIFF
+    DIFF -->|skip if disconnected| CHECK{Connected?}
+    CHECK -->|yes| AF[AddFilters]
+    CHECK -->|no| QUEUE[Queued in RelayState.repos]
+    AF -->|subscribe| CONN
+    AF -->|create batch| PSI
+    CONN -->|EOSE| PSI
+    PSI -->|batch complete| REPOS
+    CONN -->|disconnect event| DISC[Mark Disconnected + set disconnected_at]
+    DISC -->|reconnect| RECONN[On Reconnect]
+    RECONN -->|check 15min rule| RULE{disconnected > 15min?}
+    RULE -->|yes| CLEAR[Clear repos/root_events]
+    RULE -->|no| RETAIN[Keep retained state]
+    CLEAR --> REGEN[Regenerate AddFilters from RepoSyncIndex]
+    RETAIN --> RESUB[Resubscribe with since filter]
+```
+
+### Connection Lifecycle Integration
+
+The `RelayState` struct now owns both the connection and sync state:
+
+```rust
+// On disconnect (detected via RelayPoolNotification::Shutdown or handle_notifications returning)
+fn handle_disconnect(&mut self, relay_url: &str) {
+    if let Some(state) = self.relay_sync_index.write().await.get_mut(relay_url) {
+        state.connection_status = ConnectionStatus::Disconnected;
+        state.disconnected_at = Some(Timestamp::now());
+        state.connection = None;
+        
+        // Clear any pending batches for this relay
+        self.pending_sync_index.write().await.remove(relay_url);
+    }
+}
+
+// On reconnect
+async fn handle_reconnect(&mut self, relay_url: &str) -> Result<(), Error> {
+    let mut index = self.relay_sync_index.write().await;
+    let state = index.get_mut(relay_url).ok_or("Relay not in index")?;
+    
+    // Apply 15-minute state retention rule
+    if state.should_clear_state() {
+        tracing::info!("Reconnect after >15min for {}, clearing state", relay_url);
+        state.clear_sync_state();
+    }
+    
+    // Create new connection
+    state.connection_status = ConnectionStatus::Connecting;
+    let connection = RelayConnection::new(relay_url.to_string());
+    
+    // Connect with since filter if we have last_connected
+    let since = state.last_connected.map(|ts| {
+        Timestamp::from(ts.as_u64().saturating_sub(900)) // -15 min buffer
+    });
+    
+    connection.connect_and_subscribe_with_since(since).await?;
+    
+    state.connection = Some(connection);
+    state.connection_status = ConnectionStatus::Connected;
+    state.last_connected = Some(Timestamp::now());
+    state.disconnected_at = None;
+    
+    drop(index); // Release lock
+    
+    // Regenerate AddFilters from current state (either retained or fresh from RepoSyncIndex)
+    self.regenerate_filters_for_relay(relay_url).await;
+    
+    Ok(())
+}
+
+/// Regenerate AddFilters for a relay after reconnection
+async fn regenerate_filters_for_relay(&mut self, relay_url: &str) {
+    let repo_index = self.repo_sync_index.read().await;
+    let targets = derive_relay_targets(&repo_index);
+    
+    if let Some(target) = targets.get(relay_url) {
+        // Build filters for everything this relay should sync
+        let filters = build_filters(&target.repos, &target.root_events);
+        
+        // Create and process AddFilters action
+        let action = AddFilters {
+            relay_url: relay_url.to_string(),
+            repos: target.repos.clone(),
+            root_events: target.root_events.clone(),
+            filters,
+        };
+        
+        self.handle_add_filters(action).await;
+    }
+}
+```
+
+---
+
+## Action Type
+
+```rust
+/// Action sent from SelfSubscriber to SyncManager.
+/// SyncManager auto-spawns relay connections if they don't exist.
+pub struct AddFilters {
+    pub relay_url: String,
+    /// Items this action covers (for pending tracking)
+    pub repos: HashSet<String>,
+    pub root_events: HashSet<EventId>,
+    /// Pre-batched filters (each with <= 100 tags)
+    pub filters: Vec<Filter>,
+}
+```
+
+---
+
+## Core Algorithms
+
+### 1. derive_relay_targets
+
+Transform RepoSyncIndex into per-relay sync targets:
+
+```rust
+fn derive_relay_targets(
+    repo_index: &HashMap<String, RepoSyncNeeds>
+) -> HashMap<String, RelaySyncNeeds> {
+    let mut targets: HashMap<String, RelaySyncNeeds> = HashMap::new();
+    
+    for (repo_ref, needs) in repo_index {
+        for relay_url in &needs.relays {
+            let target = targets.entry(relay_url.clone()).or_default();
+            target.repos.insert(repo_ref.clone());
+            target.root_events.extend(needs.root_events.iter().cloned());
+        }
+    }
+    
+    targets
+}
+```
+
+### 2. compute_actions (Three-Way Diff)
+
+```rust
+fn compute_actions(
+    targets: &HashMap<String, RelaySyncNeeds>,
+    pending: &HashMap<String, Vec<PendingBatch>>,
+    confirmed: &HashMap<String, RelayState>,
+) -> Vec<AddFilters> {
+    let mut actions = Vec::new();
+    
+    for (relay_url, target) in targets {
+        // Skip disconnected relays - they'll get AddFilters on reconnect
+        if let Some(state) = confirmed.get(relay_url) {
+            if state.connection_status != ConnectionStatus::Connected {
+                continue;
+            }
+        }
+        
+        // Collect all pending items for this relay
+        let pending_repos: HashSet<_> = pending.get(relay_url)
+            .map(|batches| batches.iter()
+                .flat_map(|b| b.items.repos.iter().cloned())
+                .collect())
+            .unwrap_or_default();
+        let pending_events: HashSet<_> = pending.get(relay_url)
+            .map(|batches| batches.iter()
+                .flat_map(|b| b.items.root_events.iter().cloned())
+                .collect())
+            .unwrap_or_default();
+        
+        // Collect confirmed items for this relay
+        let confirmed_repos = confirmed.get(relay_url)
+            .map(|c| &c.repos)
+            .unwrap_or(&HashSet::new());
+        let confirmed_events = confirmed.get(relay_url)
+            .map(|c| &c.root_events)
+            .unwrap_or(&HashSet::new());
+        
+        // New = target - pending - confirmed
+        let new_repos: HashSet<_> = target.repos.iter()
+            .filter(|r| !pending_repos.contains(*r) && !confirmed_repos.contains(*r))
+            .cloned()
+            .collect();
+        let new_events: HashSet<_> = target.root_events.iter()
+            .filter(|e| !pending_events.contains(*e) && !confirmed_events.contains(*e))
+            .cloned()
+            .collect();
+        
+        if !new_repos.is_empty() || !new_events.is_empty() {
+            let filters = build_filters(&new_repos, &new_events);
+            actions.push(AddFilters {
+                relay_url: relay_url.clone(),
+                repos: new_repos,
+                root_events: new_events,
+                filters,
+            });
+        }
+    }
+    
+    actions
+}
+```
+
+### 3. handle_add_filters (SyncManager)
+
+```rust
+impl SyncManager {
+    async fn handle_add_filters(&mut self, action: AddFilters) {
+        let AddFilters { relay_url, repos, root_events, filters } = action;
+        
+        // Auto-spawn connection if needed
+        if !self.connections.contains_key(&relay_url) {
+            self.spawn_connection(&relay_url).await;
+        }
+        
+        let conn = self.connections.get(&relay_url).unwrap();
+        
+        // Subscribe and collect subscription IDs
+        // nostr-sdk 0.44: subscribe returns Output<Vec<SubscriptionId>>
+        // since we're only subscribed to one relay per connection
+        let mut sub_ids = HashSet::new();
+        for filter in filters {
+            // cloned filter for each subscription call
+            match conn.client.subscribe(filter, None).await {
+                Ok(output) => {
+                    // Output contains subscription IDs for each relay
+                    for sub_id in output.val {
+                        sub_ids.insert(sub_id);
+                    }
+                }
+                Err(e) => {
+                    tracing::warn!("Failed to subscribe: {}", e);
+                }
+            }
+        }
+        
+        // Create pending batch
+        let batch = PendingBatch {
+            batch_id: self.next_batch_id(),
+            items: PendingItems { repos, root_events },
+            outstanding_subs: sub_ids,
+        };
+        
+        // Add to pending index
+        self.pending_sync_index.write().await
+            .entry(relay_url)
+            .or_default()
+            .push(batch);
+    }
+}
+```
+
+### 4. handle_eose (Batch Completion)
+
+```rust
+impl SyncManager {
+    async fn handle_eose(&mut self, relay_url: &str, sub_id: SubscriptionId) {
+        let mut pending = self.pending_sync_index.write().await;
+        
+        if let Some(batches) = pending.get_mut(relay_url) {
+            // Find which batch this subscription belongs to
+            for batch in batches.iter_mut() {
+                if batch.outstanding_subs.remove(&sub_id) {
+                    // Check if batch is now complete
+                    if batch.outstanding_subs.is_empty() {
+                        // Move items to confirmed
+                        let items = batch.items.clone();
+                        drop(pending); // Release lock before acquiring another
+                        
+                        let mut confirmed = self.relay_sync_index.write().await;
+                        let relay_confirmed = confirmed
+                            .entry(relay_url.to_string())
+                            .or_default();
+                        relay_confirmed.repos.extend(items.repos);
+                        relay_confirmed.root_events.extend(items.root_events);
+                        
+                        tracing::info!(
+                            "Batch {} complete for {} - confirmed {} repos, {} events",
+                            batch.batch_id, relay_url,
+                            items.repos.len(), items.root_events.len()
+                        );
+                    }
+                    break;
+                }
+            }
+            
+            // Clean up completed batches
+            if let Some(batches) = pending.get_mut(relay_url) {
+                batches.retain(|b| !b.outstanding_subs.is_empty());
+            }
+        }
+    }
+}
+```
+
+---
+
+## Self-Subscriber Flow
+
+### State Tracking
+
+```rust
+pub struct SelfSubscriber {
+    own_relay_url: String,
+    relay_domain: String,
+    repo_sync_index: RepoSyncIndex,
+    pending_sync_index: PendingSyncIndex,
+    relay_sync_index: RelaySyncIndex,
+    action_tx: mpsc::Sender<AddFilters>,
+    /// Timestamp of last successful connection - used for since filter on reconnection
+    last_connected: Option<Timestamp>,
+    /// Is this the first connection attempt since startup?
+    is_initial_connect: bool,
+}
+```
+
+### On Startup
+
+```rust
+impl SelfSubscriber {
+    async fn run(mut self) {
+        // Connect to own relay
+        let client = Client::new(Keys::generate());
+        client.add_relay(&self.own_relay_url).await?;
+        client.connect().await;
+        
+        // Track connection time
+        self.last_connected = Some(Timestamp::now());
+        
+        // Subscribe WITHOUT since filter (get all historical) on first connect
+        let filter = Filter::new().kinds([
+            Kind::Custom(30617),  // Repository announcements
+            Kind::GitPatch,       // 1617
+            Kind::Custom(1618),   // PRs
+            Kind::Custom(1619),   // PR updates
+            Kind::GitIssue,       // 1621
+        ]);
+        
+        client.subscribe(filter, None).await?;
+        self.is_initial_connect = false;
+        
+        // Run event loop with batching
+        self.event_loop(&client).await;
+    }
+}
+```
+
+### On Reconnection
+
+```rust
+impl SelfSubscriber {
+    async fn reconnect(&mut self, client: &Client) -> Result<(), Error> {
+        // Reconnect to own relay
+        client.connect().await;
+        
+        // On reconnection ONLY, use since filter based on last_connected
+        let since = match self.last_connected {
+            Some(ts) => Timestamp::from(ts.as_u64().saturating_sub(900)), // -15 minutes buffer
+            None => Timestamp::from(0), // Shouldn't happen, but fall back to full sync
+        };
+        
+        // Update last_connected AFTER computing since
+        self.last_connected = Some(Timestamp::now());
+        
+        let filter = Filter::new()
+            .kinds([
+                Kind::Custom(30617),
+                Kind::GitPatch,
+                Kind::Custom(1618),
+                Kind::Custom(1619),
+                Kind::GitIssue,
+            ])
+            .since(since);
+        
+        client.subscribe(filter, None).await?;
+        Ok(())
+    }
+}
+```
+
+### Batching Logic
+
+```rust
+impl SelfSubscriber {
+    async fn event_loop(&self, client: &Client) {
+        let mut pending_events: Vec<Event> = Vec::new();
+        let mut batch_timer: Option<Instant> = None;
+        let batch_window = Duration::from_secs(5);
+        
+        loop {
+            let timeout = batch_timer
+                .map(|t| batch_window.saturating_sub(t.elapsed()))
+                .unwrap_or(Duration::from_secs(60));
+            
+            tokio::select! {
+                notification = client.notifications().recv() => {
+                    if let Ok(RelayPoolNotification::Event { event, .. }) = notification {
+                        pending_events.push(*event);
+                        
+                        // Start timer on first event (does NOT reset)
+                        if batch_timer.is_none() {
+                            batch_timer = Some(Instant::now());
+                        }
+                    }
+                }
+                _ = tokio::time::sleep(timeout), if batch_timer.is_some() => {
+                    // Batch window elapsed
+                    self.process_batch(pending_events.drain(..).collect()).await;
+                    batch_timer = None;
+                }
+            }
+        }
+    }
+    
+    async fn process_batch(&self, events: Vec<Event>) {
+        // 1. Update RepoSyncIndex
+        for event in events {
+            match event.kind.as_u16() {
+                30617 => self.handle_announcement(&event).await,
+                1617 | 1618 | 1619 | 1621 => self.handle_root_event(&event).await,
+                _ => {}
+            }
+        }
+        
+        // 2. Derive targets and compute actions
+        let repo_index = self.repo_sync_index.read().await;
+        let targets = derive_relay_targets(&repo_index);
+        
+        let pending = self.pending_sync_index.read().await;
+        let confirmed = self.relay_sync_index.read().await;
+        
+        let actions = compute_actions(&targets, &pending, &confirmed);
+        
+        drop(repo_index);
+        drop(pending);
+        drop(confirmed);
+        
+        // 3. Send actions to SyncManager
+        for action in actions {
+            let _ = self.action_tx.send(action).await;
+        }
+    }
+}
+```
+
+---
+
+## Bootstrap Relay
+
+```rust
+impl SyncManager {
+    async fn initialize_bootstrap(&mut self) {
+        if let Some(url) = &self.config.bootstrap_relay_url {
+            // Pre-mark as bootstrap (never removed)
+            self.relay_sync_index.write().await.insert(
+                url.clone(),
+                RelaySyncNeeds {
+                    repos: HashSet::new(),
+                    root_events: HashSet::new(),
+                    is_bootstrap: true,
+                }
+            );
+            
+            // Send Layer 1 filter
+            let filters = vec![
+                Filter::new().kinds([Kind::Custom(30617), Kind::Custom(30618)])
+            ];
+            
+            self.handle_add_filters(AddFilters {
+                relay_url: url.clone(),
+                repos: HashSet::new(),  // Layer 1 doesn't track specific repos
+                root_events: HashSet::new(),
+                filters,
+            }).await;
+        }
+    }
+}
+```
+
+---
+
+## Disconnect Handling
+
+Direct in SyncManager (not via action):
+
+```rust
+impl SyncManager {
+    async fn check_disconnects(&mut self) {
+        let confirmed = self.relay_sync_index.read().await;
+        
+        for (relay_url, state) in confirmed.iter() {
+            if state.is_bootstrap {
+                continue; // Never disconnect bootstrap
+            }
+            
+            if state.repos.is_empty() && state.root_events.is_empty() {
+                // No repos - disconnect
+                self.disconnect_relay(relay_url).await;
+            }
+        }
+    }
+    
+    async fn disconnect_relay(&mut self, relay_url: &str) {
+        self.relay_sync_index.write().await.remove(relay_url);
+        self.pending_sync_index.write().await.remove(relay_url);
+        
+        if let Some(conn) = self.connections.remove(relay_url) {
+            conn.disconnect().await;
+        }
+    }
+}
+```
+
+---
+
+## Relay Connection Lifecycle
+
+### State Machine for External Relays
+
+```mermaid
+stateDiagram-v2
+    [*] --> Connecting: spawn_connection
+    Connecting --> Connected: success
+    Connecting --> Backoff: failure
+    Connected --> Disconnected: connection lost
+    Connected --> [*]: intentional disconnect
+    Disconnected --> Backoff: record_failure
+    Backoff --> Connecting: backoff elapsed
+    Backoff --> Dead: 24h continuous failures
+    Dead --> Connecting: daily retry
+```
+
+### Health Integration
+
+Uses `RelayHealthTracker` from [`src/sync/health.rs`](../../src/sync/health.rs):
+
+```rust
+impl SyncManager {
+    /// Spawn a connection with health tracking
+    async fn spawn_connection(&mut self, relay_url: &str) {
+        // Check if we should attempt connection
+        if !self.health_tracker.should_attempt_connection(relay_url) {
+            let remaining = self.health_tracker.get_remaining_backoff(relay_url);
+            tracing::debug!(
+                "Skipping connection to {} - backoff {:?}",
+                relay_url,
+                remaining
+            );
+            return;
+        }
+        
+        match self.try_connect(relay_url).await {
+            Ok(conn) => {
+                self.health_tracker.record_success(relay_url);
+                self.connections.insert(relay_url.to_string(), conn);
+            }
+            Err(e) => {
+                self.health_tracker.record_failure(relay_url);
+                tracing::warn!("Connection to {} failed: {}", relay_url, e);
+            }
+        }
+    }
+}
+```
+
+### Reconnection Loop
+
+Each relay connection runs its own reconnection loop:
+
+```rust
+impl RelayConnection {
+    async fn run_with_reconnection(
+        mut self,
+        health_tracker: Arc<RelayHealthTracker>,
+        event_tx: mpsc::Sender<RelayEvent>,
+    ) {
+        loop {
+            // Check backoff before attempting
+            if !health_tracker.should_attempt_connection(&self.url) {
+                if let Some(remaining) = health_tracker.get_remaining_backoff(&self.url) {
+                    tokio::time::sleep(remaining).await;
+                    continue;
+                }
+            }
+            
+            // Attempt connection
+            match self.connect_and_subscribe().await {
+                Ok(()) => {
+                    health_tracker.record_success(&self.url);
+                    
+                    // Track when we connected for since filter on reconnect
+                    let connected_at = Timestamp::now();
+                    
+                    // Run event loop until disconnection
+                    self.run_event_loop(&event_tx).await;
+                    
+                    // Connection lost - will reconnect with since filter
+                    health_tracker.record_failure(&self.url);
+                    
+                    // On reconnect, use since = connected_at - 15 minutes
+                    self.set_reconnect_since(connected_at);
+                }
+                Err(e) => {
+                    health_tracker.record_failure(&self.url);
+                    tracing::warn!("Connection to {} failed: {}", self.url, e);
+                }
+            }
+            
+            // Get backoff duration and wait
+            let state = health_tracker.get_state(&self.url);
+            if state == HealthState::Dead {
+                // Dead relays retry once per 24 hours
+                tokio::time::sleep(Duration::from_secs(24 * 3600)).await;
+            }
+            // Otherwise, loop will check should_attempt_connection
+        }
+    }
+}
+```
+
+### Backoff Configuration
+
+From existing [`RelayHealthTracker`](../../src/sync/health.rs:91):
+
+| Parameter | Value | Notes |
+|-----------|-------|-------|
+| Base backoff | 5 seconds | First failure |
+| Backoff multiplier | 2x | Exponential increase |
+| Max backoff | 1 hour (configurable) | `sync_max_backoff_secs` |
+| Dead threshold | 24 hours | Continuous failures |
+| Dead retry interval | 24 hours | Once per day |
+
+---
+
+## Consolidation
+
+### Threshold-Based (70 filters)
+
+```rust
+impl SyncManager {
+    async fn maybe_consolidate(&mut self, relay_url: &str) {
+        let filter_count = self.get_filter_count(relay_url).await;
+        
+        if filter_count > 70 {
+            self.consolidate(relay_url).await;
+        }
+    }
+    
+    async fn consolidate(&mut self, relay_url: &str) {
+        // 1. Wait for all pending batches to complete
+        self.wait_pending_complete(relay_url).await;
+        
+        // 2. Close all subscriptions
+        self.close_all_subs(relay_url).await;
+        
+        // 3. Rebuild filters from confirmed state
+        let confirmed = self.relay_sync_index.read().await;
+        let state = confirmed.get(relay_url)?;
+        let filters = build_filters(&state.repos, &state.root_events);
+        
+        // 4. Resubscribe with since = now - 15 minutes
+        let since = Timestamp::now() - 900;
+        for filter in filters {
+            self.subscribe(relay_url, filter.since(since)).await;
+        }
+    }
+}
+```
+
+### Daily Timer (23-25h Random)
+
+```rust
+impl SyncManager {
+    async fn run_daily_consolidation(&self) {
+        loop {
+            let hours = 23 + rand::random::<f64>() * 2.0;
+            tokio::time::sleep(Duration::from_secs_f64(hours * 3600.0)).await;
+            
+            for relay_url in self.connections.keys() {
+                self.consolidate(relay_url).await;
+            }
+        }
+    }
+}
+```
+
+---
+
+## Key Design Decisions
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Startup mechanism | Self-subscription only | Single code path, fresh DB behaves same as reconnect |
+| Since filter | Only on reconnection | Initial subscribe gets full history |
+| Pending tracking | Per-batch with batch ID | Independent confirmation, no blocking |
+| EOSE requirement | All subs in batch must complete | Single repo may need multiple filter subs |
+| Action type | Struct not enum | Only one action type needed |
+| Relay spawning | Auto-spawn on AddFilters | Simplifies action logic |
+| Disconnect | Direct in SyncManager | Not worth an action type |
+| Consolidation | 70 filters + daily timer | Threshold for growth, timer for staleness |
+| Timestamps | In-memory only | Not critical for correctness |
+| Health tracking | Reuse existing RelayHealthTracker | Already implements exponential backoff, dead relay detection |
+| Reconnection backoff | Exponential to 1h max | Prevents hammering failed relays |
+| Dead relay policy | 24h threshold, daily retry | Balance between giving up and resource waste |
+| last_connected tracking | Per-connection in-memory | Enables 15-minute buffer on reconnect |
+| Connection ownership | Inside RelayState | Ties connection lifecycle to sync state, simpler than separate maps |
+| State retention rule | Clear if disconnected >15min | Matches since filter buffer, prevents stale subscriptions |
+| Skip disconnected | compute_actions skips disconnected | Prevents queuing AddFilters for offline relays |
+| Reconnect triggers | handle_notifications returns or Shutdown | nostr-sdk signals disconnect via event loop exit |
+| On-reconnect flow | Regenerate AddFilters from RepoSyncIndex | Fresh subscriptions for what we actually need |
+
+---
+
+## Module Structure
+
+```
+src/sync/
+├── mod.rs              # SyncManager, main loop
+├── state.rs            # RepoSyncIndex, RelaySyncIndex, PendingSyncIndex types
+├── actions.rs          # AddFilters struct, compute_actions
+├── self_subscriber.rs  # SelfSubscriber, batching logic
+├── relay_connection.rs # Per-relay WebSocket connection
+├── consolidation.rs    # Consolidation logic, daily timer
+├── health.rs           # Health tracking (reuse from v2)
+└── metrics.rs          # Prometheus metrics (reuse from v2)
\ No newline at end of file
diff --git a/docs/explanation/grasp-02-proactive-sync-v4.md b/docs/explanation/grasp-02-proactive-sync-v4.md
new file mode 100644
index 0000000..aba88a5
--- /dev/null
+++ b/docs/explanation/grasp-02-proactive-sync-v4.md
@@ -0,0 +1,1229 @@
+# GRASP-02: Proactive Sync v4 - Health & Reconnection Design
+
+## Overview
+
+This document presents v4 of the proactive sync design, refining the connection lifecycle and reconnection patterns. Key principles:
+
+1. **Self-subscription as the only mechanism** - No database initialization at startup
+2. **compute_actions as single decision point** - Determines what NEW subscriptions to create
+3. **Two subscription paths on reconnect** - Catch-up (retained, with since) vs new items (via compute_actions)
+4. **Blank state = fresh sync** - Empty confirmed state triggers full historical fetch
+5. **Clear on disconnect, not reconnect** - PendingSyncIndex cleared at event boundary
+
+---
+
+## Data Model
+
+### RepoSyncIndex (Source of Truth)
+
+```rust
+/// What we WANT to sync - derived from events received via self-subscription.
+/// Updated immediately when self-subscriber batch fires.
+/// Key: repo addressable ref - 30617:pubkey:identifier
+pub type RepoSyncIndex = Arc<RwLock<HashMap<String, RepoSyncNeeds>>>;
+
+#[derive(Debug, Clone, Default)]
+pub struct RepoSyncNeeds {
+    /// Relay URLs listed in this repo's 30617 announcement
+    pub relays: HashSet<String>,
+    /// Root event IDs - 1617/1618/1619/1621 - that reference this repo
+    pub root_events: HashSet<EventId>,
+}
+```
+
+### RelaySyncIndex (Confirmed State + Connection)
+
+```rust
+/// What we have CONFIRMED syncing - includes connection state for integrated lifecycle.
+/// Key: relay URL
+pub type RelaySyncIndex = Arc<RwLock<HashMap<String, RelayState>>>;
+
+/// Connection status for a relay
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ConnectionStatus {
+    /// Not currently connected
+    Disconnected,
+    /// Connection attempt in progress
+    Connecting,
+    /// Successfully connected and subscribed
+    Connected,
+}
+
+/// Complete state for a single relay - combines sync needs with connection lifecycle
+#[derive(Debug)]
+pub struct RelayState {
+    /// Repos we have confirmed syncing from this relay
+    pub repos: HashSet<String>,
+    /// Root events we have confirmed tracking
+    pub root_events: HashSet<EventId>,
+    /// If true, never disconnect this relay
+    pub is_bootstrap: bool,
+    /// Current connection status
+    pub connection_status: ConnectionStatus,
+    /// When we last successfully connected - used for since filter on reconnect
+    pub last_connected: Option<Timestamp>,
+    /// When we disconnected - for 15-minute state retention rule
+    pub disconnected_at: Option<Timestamp>,
+    /// The active connection - None if disconnected
+    pub connection: Option<RelayConnection>,
+}
+
+impl RelayState {
+    /// Check if state should be cleared based on 15-minute rule
+    pub fn should_clear_state(&self) -> bool {
+        match self.disconnected_at {
+            Some(disconnected) => {
+                let now = Timestamp::now();
+                now.as_u64().saturating_sub(disconnected.as_u64()) > 900 // 15 minutes
+            }
+            None => false, // Still connected or never connected
+        }
+    }
+    
+    /// Clear repos and root_events - called when reconnect takes > 15 minutes
+    pub fn clear_sync_state(&mut self) {
+        self.repos.clear();
+        self.root_events.clear();
+    }
+}
+```
+
+### PendingSyncIndex (In-Flight Batches)
+
+```rust
+/// Tracks batches of subscriptions that are in-flight, awaiting EOSE.
+/// Each batch has its own ID and can confirm independently.
+/// Key: relay URL
+pub type PendingSyncIndex = Arc<RwLock<HashMap<String, Vec<PendingBatch>>>>;
+
+#[derive(Debug, Clone)]
+pub struct PendingBatch {
+    /// Unique ID for this batch - for debugging/logging
+    pub batch_id: u64,
+    /// The items this batch is syncing
+    pub items: PendingItems,
+    /// Subscription IDs that must ALL receive EOSE before confirming
+    pub outstanding_subs: HashSet<SubscriptionId>,
+}
+
+#[derive(Debug, Clone, Default)]
+pub struct PendingItems {
+    pub repos: HashSet<String>,
+    pub root_events: HashSet<EventId>,
+}
+```
+
+---
+
+## Connection Lifecycle State Machine
+
+```mermaid
+stateDiagram-v2
+    [*] --> Disconnected: discover relay via RepoSyncIndex
+    Disconnected --> Connecting: AddFilters triggers spawn_connection
+    Connecting --> Connected: success
+    Connecting --> Disconnected: failure + record in health tracker
+    Connected --> Disconnected: connection lost
+    Connected --> [*]: intentional disconnect via check_disconnects
+    
+    note right of Disconnected: disconnected_at set for 15min rule
+    note right of Connected: last_connected tracked for since filter
+```
+
+---
+
+## Flow Scenarios
+
+### Scenario 1: Initial Connect via handle_connect_or_reconnect
+
+```mermaid
+flowchart TB
+    START[Startup] --> SS[Self-subscribe to own relay]
+    SS --> |no since filter| EVENTS[Receive historical events]
+    EVENTS --> RSI[Update RepoSyncIndex]
+    RSI --> DT[derive_relay_targets]
+    DT --> CA[compute_actions with targets and empty confirmed]
+    CA --> AF[AddFilters for each relay]
+    AF --> SPAWN{Relay connected?}
+    SPAWN --> |no| CONN[spawn_connection]
+    CONN --> HC[handle_connect_or_reconnect]
+    SPAWN --> |yes| SUB
+    
+    subgraph handle_connect_or_reconnect - Fresh Sync
+        HC --> CHECK_FRESH{is_fresh_sync?}
+        CHECK_FRESH --> |yes - no last_connected| L1[build_announcement_filter - no since]
+        L1 --> RCA[recompute_actions_for_relay]
+    end
+    
+    RCA --> SUB[Subscribe Layer 2+3 filters via AddFilters]
+    SUB --> PB[Create PendingBatch]
+    PB --> EOSE[Wait for EOSE]
+    EOSE --> CONFIRM[Move items to confirmed repos/root_events]
+```
+
+**Key points:**
+- No `since` filter on initial connect - get full history
+- `handle_connect_or_reconnect` detects `is_fresh_sync` via `last_connected.is_none()`
+- Layer 1: `build_announcement_filter(None)` - subscribed immediately without since
+- Layer 2+3: handled via `recompute_actions_for_relay` → `compute_actions` with PendingBatch tracking
+
+### Scenario 2: Quick Reconnect via handle_connect_or_reconnect - less than 15 minutes
+
+```mermaid
+flowchart TB
+    DISC[Connection lost] --> MARK[Set disconnected_at = now]
+    MARK --> CLEAR_PEND[Clear PendingSyncIndex for relay]
+    CLEAR_PEND --> WAIT[Wait for reconnection]
+    WAIT --> RECONN[Connection restored]
+    RECONN --> HC[handle_connect_or_reconnect]
+    
+    subgraph handle_connect_or_reconnect - Quick Reconnect
+        HC --> CHECK{is_fresh_sync?}
+        CHECK --> |no - last_connected exists AND <15min| SINCE[since = last_connected - 15min]
+        SINCE --> L1[build_announcement_filter - with since]
+        L1 --> L23[rebuild_layer2_and_layer3 - with since]
+        L23 --> RCA[recompute_actions_for_relay]
+    end
+    
+    RCA --> AF[AddFilters for new items only]
+    AF --> SUB[Subscribe]
+    SUB --> PB[Create PendingBatch]
+    PB --> EOSE[Wait for EOSE]
+    EOSE --> EXTEND[Extend confirmed state]
+```
+
+**Key points:**
+- PendingSyncIndex cleared on disconnect (not reconnect)
+- `handle_connect_or_reconnect`:
+  1. `build_announcement_filter(Some(since))` - Layer 1 with since
+  2. `rebuild_layer2_and_layer3(since)` - Layer 2+3 with since
+  3. `recompute_actions_for_relay` - check for new items
+- since = last_connected - 15min ensures we catch events during disconnection
+
+### Scenario 3: Stale Reconnect via handle_connect_or_reconnect - greater than 15 minutes
+
+```mermaid
+flowchart TB
+    RECONN[Connection restored] --> HC[handle_connect_or_reconnect]
+    
+    subgraph handle_connect_or_reconnect - Stale Reconnect
+        HC --> CHECK{is_fresh_sync?}
+        CHECK --> |yes - disconnected >15min| CLEAR[clear_sync_state]
+        CLEAR --> L1[build_announcement_filter - no since]
+        L1 --> RCA[recompute_actions_for_relay]
+    end
+    
+    RCA --> CA[compute_actions with empty confirmed]
+    CA --> AF[AddFilters for everything]
+    AF --> SUB[Subscribe - no since filter]
+    SUB --> PB[Create PendingBatch]
+    PB --> EOSE[Wait for EOSE]
+    EOSE --> CONFIRM[Populate confirmed state fresh]
+```
+
+**Key points:**
+- `should_clear_state()` returns true → triggers fresh sync
+- Same path as initial connect after clearing state
+- Layer 1: `build_announcement_filter(None)` - full history
+- Layer 2+3: handled via empty confirmed state → compute_actions generates AddFilters for everything
+
+### Scenario 4: Consolidation - Triggered on Filter Add
+
+```mermaid
+flowchart TB
+    AF[handle_add_filters called] --> COUNT{current + new > 70?}
+    COUNT --> |yes| CONSOLIDATE[consolidate]
+    CONSOLIDATE --> WAIT_PEND[wait_pending_complete]
+    WAIT_PEND --> CLOSE[unsubscribe_all]
+    CLOSE --> SINCE[since = now - 15min]
+    SINCE --> L1[build_announcement_filter - with since]
+    L1 --> L23[rebuild_layer2_and_layer3 - with since]
+    COUNT --> |no| SUB[Subscribe new filters]
+    SUB --> PB[Create PendingBatch]
+```
+
+**Key points:**
+- Consolidation checked in `handle_add_filters` BEFORE adding new filters
+- After closing all subscriptions, re-subscribe:
+  1. `build_announcement_filter(Some(since))` - Layer 1 stays active with since
+  2. `rebuild_layer2_and_layer3(since)` - Layer 2+3 with since
+- `since = now - 15min` prevents re-fetching old events
+- Keeps confirmed state, just reduces filter count
+
+### Scenario 5: Daily Timer - 23 to 25h Random
+
+```mermaid
+flowchart TB
+    DAILY[Daily timer fires] --> CLOSE[unsubscribe_all]
+    CLOSE --> CLEAR_PEND[Clear PendingSyncIndex for relay]
+    CLEAR_PEND --> CLEAR_STATE[clear_sync_state]
+    CLEAR_STATE --> L1[build_announcement_filter - no since]
+    L1 --> RCA[recompute_actions_for_relay]
+    RCA --> CA[compute_actions with empty confirmed]
+    CA --> AF[AddFilters for everything]
+    AF --> SUB[Subscribe - no since filter]
+    SUB --> PB[Create PendingBatch]
+    PB --> EOSE[Wait for EOSE]
+    EOSE --> CONFIRM[Repopulate confirmed state]
+```
+
+**Key points:**
+- Daily timer is a full fresh sync, NOT consolidation
+- Clears both PendingSyncIndex and confirmed state
+- Layer 1: `build_announcement_filter(None)` - full history
+- Layer 2+3: via compute_actions with empty confirmed - full history
+- Detects any state drift accumulated over 24 hours
+
+---
+
+## Core Algorithms
+
+### 1. derive_relay_targets
+
+Transform RepoSyncIndex into per-relay sync targets:
+
+```rust
+/// Inverts RepoSyncIndex to get per-relay view
+fn derive_relay_targets(
+    repo_index: &HashMap<String, RepoSyncNeeds>
+) -> HashMap<String, RelaySyncNeeds> {
+    let mut targets: HashMap<String, RelaySyncNeeds> = HashMap::new();
+    
+    for (repo_ref, needs) in repo_index {
+        for relay_url in &needs.relays {
+            let target = targets.entry(relay_url.clone()).or_default();
+            target.repos.insert(repo_ref.clone());
+            target.root_events.extend(needs.root_events.iter().cloned());
+        }
+    }
+    
+    targets
+}
+```
+
+### 2. compute_actions (Three-Way Diff)
+
+**This is the ONLY decision point for what NEW subscriptions to create.**
+
+```rust
+/// Computes AddFilters for items that are:
+/// - In targets (what we want)
+/// - NOT in pending (already in-flight)
+/// - NOT in confirmed (already confirmed)
+fn compute_actions(
+    targets: &HashMap<String, RelaySyncNeeds>,
+    pending: &HashMap<String, Vec<PendingBatch>>,
+    confirmed: &HashMap<String, RelayState>,
+) -> Vec<AddFilters> {
+    let mut actions = Vec::new();
+    
+    for (relay_url, target) in targets {
+        // Skip disconnected relays - they will get AddFilters on reconnect
+        if let Some(state) = confirmed.get(relay_url) {
+            if state.connection_status != ConnectionStatus::Connected {
+                continue;
+            }
+        }
+        
+        // Collect all pending items for this relay
+        let pending_repos: HashSet<_> = pending.get(relay_url)
+            .map(|batches| batches.iter()
+                .flat_map(|b| b.items.repos.iter().cloned())
+                .collect())
+            .unwrap_or_default();
+        let pending_events: HashSet<_> = pending.get(relay_url)
+            .map(|batches| batches.iter()
+                .flat_map(|b| b.items.root_events.iter().cloned())
+                .collect())
+            .unwrap_or_default();
+        
+        // Collect confirmed items for this relay
+        let confirmed_repos = confirmed.get(relay_url)
+            .map(|c| &c.repos)
+            .unwrap_or(&HashSet::new());
+        let confirmed_events = confirmed.get(relay_url)
+            .map(|c| &c.root_events)
+            .unwrap_or(&HashSet::new());
+        
+        // New = target - pending - confirmed
+        let new_repos: HashSet<_> = target.repos.iter()
+            .filter(|r| !pending_repos.contains(*r) && !confirmed_repos.contains(*r))
+            .cloned()
+            .collect();
+        let new_events: HashSet<_> = target.root_events.iter()
+            .filter(|e| !pending_events.contains(*e) && !confirmed_events.contains(*e))
+            .cloned()
+            .collect();
+        
+        if !new_repos.is_empty() || !new_events.is_empty() {
+            let filters = build_filters(&new_repos, &new_events);
+            actions.push(AddFilters {
+                relay_url: relay_url.clone(),
+                repos: new_repos,
+                root_events: new_events,
+                filters,
+            });
+        }
+    }
+    
+    actions
+}
+```
+
+### 3. Filter Building Functions (Three-Layer Strategy)
+
+The filter strategy uses three layers:
+- **Layer 1**: Announcements (30617/30618) - subscribed ONCE on connect, NOT rebuilt during consolidation
+- **Layer 2**: Events tagging our repos
+- **Layer 3**: Events tagging our root events
+
+**Key insight**: Layer 1 is connection-level (subscribe once), Layer 2+3 are item-level (managed by compute_actions and PendingBatch).
+
+```rust
+/// Layer 1: Announcements filter (kinds 30617 + 30618)
+/// Subscribed ONCE on connect - NOT included in consolidation rebuilds.
+/// Note: 30618 is ONLY synced from remote relays, not self-subscribed.
+fn build_announcement_filter(since: Option<Timestamp>) -> Filter {
+    let filter = Filter::new().kinds([
+        Kind::Custom(30617),  // Repository announcements
+        Kind::Custom(30618),  // Maintainer lists
+    ]);
+    
+    match since {
+        Some(ts) => filter.since(ts),
+        None => filter,
+    }
+}
+
+/// Layer 2: Events tagging one of our repos
+/// Uses lowercase a, uppercase A, and q tags for comprehensive coverage.
+/// Batched per 100 repo refs.
+fn tagged_one_of_our_repo_event_filters(
+    repos: &HashSet<String>,
+    since: Option<Timestamp>,
+) -> Vec<Filter> {
+    let mut filters = Vec::new();
+    let repo_refs: Vec<_> = repos.iter().collect();
+    
+    for chunk in repo_refs.chunks(100) {
+        let chunk_vec: Vec<&str> = chunk.iter().map(|s| s.as_str()).collect();
+        
+        // Lowercase 'a' tag - standard addressable reference
+        let mut f1 = Filter::new()
+            .custom_tag(SingleLetterTag::lowercase(Alphabet::A), chunk_vec.clone());
+        // Uppercase 'A' tag - some clients use this
+        let mut f2 = Filter::new()
+            .custom_tag(SingleLetterTag::uppercase(Alphabet::A), chunk_vec.clone());
+        // Quote 'q' tag - NIP-10 quote references to addressable events
+        let mut f3 = Filter::new()
+            .custom_tag(SingleLetterTag::lowercase(Alphabet::Q), chunk_vec);
+        
+        if let Some(ts) = since {
+            f1 = f1.since(ts);
+            f2 = f2.since(ts);
+            f3 = f3.since(ts);
+        }
+        
+        filters.push(f1);
+        filters.push(f2);
+        filters.push(f3);
+    }
+    
+    filters
+}
+
+/// Layer 3: Events tagging one of our root events
+/// Uses lowercase e, uppercase E, and q tags for comprehensive coverage.
+/// Batched per 100 event IDs.
+fn tagged_one_of_our_root_event_filters(
+    root_events: &HashSet<EventId>,
+    since: Option<Timestamp>,
+) -> Vec<Filter> {
+    let mut filters = Vec::new();
+    let event_ids: Vec<String> = root_events.iter().map(|id| id.to_hex()).collect();
+    
+    for chunk in event_ids.chunks(100) {
+        let chunk_vec: Vec<&str> = chunk.iter().map(|s| s.as_str()).collect();
+        
+        // Lowercase 'e' tag - standard event reference
+        let mut f1 = Filter::new()
+            .custom_tag(SingleLetterTag::lowercase(Alphabet::E), chunk_vec.clone());
+        // Uppercase 'E' tag - some clients use this
+        let mut f2 = Filter::new()
+            .custom_tag(SingleLetterTag::uppercase(Alphabet::E), chunk_vec.clone());
+        // Quote 'q' tag - NIP-10 quote references to events
+        let mut f3 = Filter::new()
+            .custom_tag(SingleLetterTag::lowercase(Alphabet::Q), chunk_vec);
+        
+        if let Some(ts) = since {
+            f1 = f1.since(ts);
+            f2 = f2.since(ts);
+            f3 = f3.since(ts);
+        }
+        
+        filters.push(f1);
+        filters.push(f2);
+        filters.push(f3);
+    }
+    
+    filters
+}
+
+/// Builds Layer 2 + Layer 3 filters only (NOT Layer 1)
+/// Used by:
+/// - compute_actions for incremental subscriptions
+/// - consolidation rebuilds (Layer 1 remains active)
+fn build_layer2_and_layer3_filters(
+    repos: &HashSet<String>,
+    root_events: &HashSet<EventId>,
+    since: Option<Timestamp>,
+) -> Vec<Filter> {
+    let mut filters = Vec::new();
+    filters.extend(tagged_one_of_our_repo_event_filters(repos, since));
+    filters.extend(tagged_one_of_our_root_event_filters(root_events, since));
+    filters
+}
+```
+
+**Note**: There is no `build_all_filters` function. Layer 1 is subscribed separately on connect, and Layer 2+3 are managed independently.
+
+### 4. handle_add_filters (SyncManager)
+
+```rust
+impl SyncManager {
+    async fn handle_add_filters(&mut self, action: AddFilters) {
+        let AddFilters { relay_url, repos, root_events, filters } = action;
+        
+        // Auto-spawn connection if needed
+        let state = self.relay_sync_index.read().await.get(&relay_url).cloned();
+        match state {
+            None => {
+                // New relay discovered - create entry and spawn connection
+                self.relay_sync_index.write().await.insert(
+                    relay_url.clone(),
+                    RelayState {
+                        repos: HashSet::new(),
+                        root_events: HashSet::new(),
+                        is_bootstrap: false,
+                        connection_status: ConnectionStatus::Connecting,
+                        last_connected: None,
+                        disconnected_at: None,
+                        connection: None,
+                    }
+                );
+                self.spawn_connection(&relay_url).await;
+                return; // Subscriptions will happen on connection success
+            }
+            Some(state) if state.connection_status != ConnectionStatus::Connected => {
+                // Not connected - subscriptions will happen on connection success
+                return;
+            }
+            Some(_) => {
+                // Already connected - proceed with subscription
+            }
+        }
+        
+        // Subscribe and collect subscription IDs
+        let conn = self.connections.get(&relay_url).unwrap();
+        let mut sub_ids = HashSet::new();
+        
+        for filter in filters {
+            match conn.client.subscribe(filter, None).await {
+                Ok(output) => {
+                    for sub_id in output.val {
+                        sub_ids.insert(sub_id);
+                    }
+                }
+                Err(e) => {
+                    tracing::warn!("Failed to subscribe: {}", e);
+                }
+            }
+        }
+        
+        // Create pending batch
+        let batch = PendingBatch {
+            batch_id: self.next_batch_id(),
+            items: PendingItems { repos, root_events },
+            outstanding_subs: sub_ids,
+        };
+        
+        // Add to pending index
+        self.pending_sync_index.write().await
+            .entry(relay_url)
+            .or_default()
+            .push(batch);
+    }
+}
+```
+
+### 5. handle_disconnect
+
+```rust
+impl SyncManager {
+    /// Called when connection to a relay is lost
+    async fn handle_disconnect(&mut self, relay_url: &str) {
+        let mut index = self.relay_sync_index.write().await;
+        
+        if let Some(state) = index.get_mut(relay_url) {
+            state.connection_status = ConnectionStatus::Disconnected;
+            state.disconnected_at = Some(Timestamp::now());
+            state.connection = None;
+        }
+        
+        // Clear pending batches - these items were not confirmed
+        self.pending_sync_index.write().await.remove(relay_url);
+        
+        // Remove from active connections map
+        self.connections.remove(relay_url);
+        
+        // Health tracker records failure for backoff
+        self.health_tracker.record_failure(relay_url);
+    }
+}
+```
+
+### 6. handle_connect_or_reconnect (Unified)
+
+This method handles BOTH initial connection AND reconnection with unified logic:
+
+```rust
+impl SyncManager {
+    /// Called when connection to a relay succeeds - handles both initial connect and reconnect.
+    ///
+    /// Decision tree:
+    /// - Fresh sync (no last_connected OR disconnected >15min): No since filter, full history
+    /// - Quick reconnect (<15min): since = last_connected - 15min
+    async fn handle_connect_or_reconnect(&mut self, relay_url: &str) {
+        let mut index = self.relay_sync_index.write().await;
+        let state = match index.get_mut(relay_url) {
+            Some(s) => s,
+            None => return, // Relay was removed while disconnected
+        };
+        
+        // Determine if this is a fresh sync or quick reconnect
+        let is_fresh_sync = state.last_connected.is_none() || state.should_clear_state();
+        let last_connected = state.last_connected;
+        
+        if is_fresh_sync && state.last_connected.is_some() {
+            // Stale reconnect (>15min) - clear state
+            tracing::info!("Reconnect after >15min for {}, clearing state for fresh sync", relay_url);
+            state.clear_sync_state();
+        }
+        
+        // Update connection state
+        state.connection_status = ConnectionStatus::Connected;
+        state.last_connected = Some(Timestamp::now());
+        state.disconnected_at = None;
+        
+        // Record success in health tracker
+        self.health_tracker.record_success(relay_url);
+        
+        drop(index); // Release lock
+        
+        let conn = match self.connections.get(relay_url) {
+            Some(c) => c,
+            None => return,
+        };
+        
+        if is_fresh_sync {
+            // Fresh sync: Layer 1 without since, Layer 2+3 handled by compute_actions
+            
+            // Step 1: Subscribe Layer 1 (announcements) without since
+            let layer1 = build_announcement_filter(None);
+            let _ = conn.client.subscribe(layer1, None).await;
+            
+            // Step 2: compute_actions will handle Layer 2+3 (with since=None in build)
+            self.recompute_actions_for_relay(relay_url).await;
+        } else {
+            // Quick reconnect: Layer 1 with since, Layer 2+3 with since
+            let since = last_connected
+                .map(|ts| Timestamp::from(ts.as_u64().saturating_sub(900)))
+                .unwrap_or(Timestamp::from(0));
+            
+            // Step 1: Subscribe Layer 1 (announcements) with since
+            let layer1 = build_announcement_filter(Some(since));
+            let _ = conn.client.subscribe(layer1, None).await;
+            
+            // Step 2: Rebuild Layer 2+3 for confirmed items with since
+            self.rebuild_layer2_and_layer3(relay_url, Some(since)).await;
+            
+            // Step 3: Check for NEW items via compute_actions
+            self.recompute_actions_for_relay(relay_url).await;
+        }
+    }
+    
+    /// Rebuild Layer 2+3 subscriptions only (NOT Layer 1).
+    /// Used by:
+    /// - Quick reconnect: rebuild confirmed items with since filter
+    /// - Consolidation: close and rebuild with since filter
+    async fn rebuild_layer2_and_layer3(&mut self, relay_url: &str, since: Option<Timestamp>) {
+        let confirmed = self.relay_sync_index.read().await;
+        let state = match confirmed.get(relay_url) {
+            Some(s) => s,
+            None => return,
+        };
+        
+        // Build Layer 2+3 filters WITH since
+        let filters = build_layer2_and_layer3_filters(&state.repos, &state.root_events, since);
+        drop(confirmed);
+        
+        // Subscribe directly - no PendingBatch for catch-up (items already confirmed)
+        let conn = match self.connections.get(relay_url) {
+            Some(c) => c,
+            None => return,
+        };
+        
+        for filter in filters {
+            let _ = conn.client.subscribe(filter, None).await;
+        }
+    }
+    
+    /// Rerun compute_actions for a specific relay and process resulting AddFilters.
+    /// compute_actions builds Layer 2+3 filters for NEW items not yet in confirmed state.
+    async fn recompute_actions_for_relay(&mut self, relay_url: &str) {
+        let repo_index = self.repo_sync_index.read().await;
+        let targets = derive_relay_targets(&repo_index);
+        drop(repo_index);
+        
+        // Filter to just this relay
+        let target = match targets.get(relay_url) {
+            Some(t) => t.clone(),
+            None => return, // No repos reference this relay anymore
+        };
+        
+        let pending = self.pending_sync_index.read().await;
+        let confirmed = self.relay_sync_index.read().await;
+        
+        let mut single_relay_targets = HashMap::new();
+        single_relay_targets.insert(relay_url.to_string(), target);
+        
+        let actions = compute_actions(&single_relay_targets, &pending, &confirmed);
+        
+        drop(pending);
+        drop(confirmed);
+        
+        // Process AddFilters
+        for action in actions {
+            self.handle_add_filters(action).await;
+        }
+    }
+}
+```
+
+### 7. Daily Timer
+
+```rust
+impl SyncManager {
+    async fn run_daily_timer(&self) {
+        loop {
+            // Random 23-25 hours
+            let hours = 23.0 + rand::random::<f64>() * 2.0;
+            tokio::time::sleep(Duration::from_secs_f64(hours * 3600.0)).await;
+            
+            let relay_urls: Vec<_> = self.relay_sync_index.read().await
+                .keys()
+                .cloned()
+                .collect();
+            
+            for relay_url in relay_urls {
+                self.daily_sync(&relay_url).await;
+            }
+        }
+    }
+    
+    /// Perform daily fresh sync for a relay
+    async fn daily_sync(&mut self, relay_url: &str) {
+        tracing::info!("Daily sync triggered for {}", relay_url);
+        
+        // Close all subscriptions
+        if let Some(conn) = self.connections.get(relay_url) {
+            conn.client.unsubscribe_all().await;
+        }
+        
+        // Clear PendingSyncIndex
+        self.pending_sync_index.write().await.remove(relay_url);
+        
+        // Clear confirmed state - triggers fresh sync
+        {
+            let mut index = self.relay_sync_index.write().await;
+            if let Some(state) = index.get_mut(relay_url) {
+                state.clear_sync_state();
+            }
+        }
+        
+        // Recompute actions - will generate AddFilters for everything
+        self.recompute_actions_for_relay(relay_url).await;
+    }
+}
+```
+
+### 8. Consolidation (Threshold-Based, Triggered on Add)
+
+Consolidation is checked when adding new subscriptions, not periodically. **Key insight**: Consolidation only closes and rebuilds Layer 2+3 - Layer 1 remains active.
+
+```rust
+impl SyncManager {
+    /// Check filter count and consolidate if needed.
+    /// Called from handle_add_filters BEFORE adding new filters.
+    async fn maybe_consolidate(&mut self, relay_url: &str, new_filter_count: usize) {
+        let current_count = self.get_filter_count(relay_url).await;
+        
+        if current_count + new_filter_count > 70 {
+            self.consolidate(relay_url).await;
+        }
+    }
+    
+    /// Consolidate filters - only rebuilds Layer 2+3, Layer 1 stays active.
+    /// Does NOT clear state - just reduces filter count.
+    async fn consolidate(&mut self, relay_url: &str) {
+        tracing::info!("Consolidating filters for {} (count > 70)", relay_url);
+        
+        // Wait for all pending batches to complete first
+        self.wait_pending_complete(relay_url).await;
+        
+        // Close Layer 2+3 subscriptions only - Layer 1 remains active
+        // NOTE: In practice, we close all then re-add Layer 1, or track sub IDs separately
+        // For simplicity, we close all and re-add Layer 1
+        if let Some(conn) = self.connections.get(relay_url) {
+            conn.client.unsubscribe_all().await;
+        }
+        
+        // Re-subscribe Layer 1 with since (maintains announcements stream)
+        let since = Timestamp::from(Timestamp::now().as_u64().saturating_sub(900));
+        let conn = self.connections.get(relay_url).unwrap();
+        let layer1 = build_announcement_filter(Some(since));
+        let _ = conn.client.subscribe(layer1, None).await;
+        
+        // Rebuild Layer 2+3 only
+        self.rebuild_layer2_and_layer3(relay_url, Some(since)).await;
+    }
+}
+```
+
+**Updated handle_add_filters to check consolidation:**
+
+```rust
+impl SyncManager {
+    async fn handle_add_filters(&mut self, action: AddFilters) {
+        let AddFilters { relay_url, repos, root_events, filters } = action;
+        
+        // Auto-spawn connection if needed (unchanged)
+        let state = self.relay_sync_index.read().await.get(&relay_url).cloned();
+        match state {
+            None => {
+                // New relay discovered - create entry and spawn connection
+                self.relay_sync_index.write().await.insert(
+                    relay_url.clone(),
+                    RelayState {
+                        repos: HashSet::new(),
+                        root_events: HashSet::new(),
+                        is_bootstrap: false,
+                        connection_status: ConnectionStatus::Connecting,
+                        last_connected: None,
+                        disconnected_at: None,
+                        connection: None,
+                    }
+                );
+                self.spawn_connection(&relay_url).await;
+                return; // Subscriptions will happen on connection success
+            }
+            Some(state) if state.connection_status != ConnectionStatus::Connected => {
+                return; // Not connected - subscriptions will happen on connection success
+            }
+            Some(_) => {
+                // Already connected - proceed
+            }
+        }
+        
+        // CHECK CONSOLIDATION BEFORE ADDING
+        self.maybe_consolidate(&relay_url, filters.len()).await;
+        
+        // Subscribe and collect subscription IDs
+        let conn = self.connections.get(&relay_url).unwrap();
+        let mut sub_ids = HashSet::new();
+        
+        for filter in filters {
+            match conn.client.subscribe(filter, None).await {
+                Ok(output) => {
+                    for sub_id in output.val {
+                        sub_ids.insert(sub_id);
+                    }
+                }
+                Err(e) => {
+                    tracing::warn!("Failed to subscribe: {}", e);
+                }
+            }
+        }
+        
+        // Create pending batch (unchanged)
+        let batch = PendingBatch {
+            batch_id: self.next_batch_id(),
+            items: PendingItems { repos, root_events },
+            outstanding_subs: sub_ids,
+        };
+        
+        self.pending_sync_index.write().await
+            .entry(relay_url)
+            .or_default()
+            .push(batch);
+    }
+}
+```
+
+---
+
+## Disconnect (Relay Removal) Handling
+
+```rust
+impl SyncManager {
+    /// Periodically check for relays that should be disconnected
+    async fn check_disconnects(&mut self) {
+        let confirmed = self.relay_sync_index.read().await;
+        let relays_to_disconnect: Vec<_> = confirmed.iter()
+            .filter(|(_, state)| {
+                !state.is_bootstrap && 
+                state.repos.is_empty() && 
+                state.root_events.is_empty()
+            })
+            .map(|(url, _)| url.clone())
+            .collect();
+        drop(confirmed);
+        
+        for relay_url in relays_to_disconnect {
+            self.disconnect_relay(&relay_url).await;
+        }
+    }
+    
+    async fn disconnect_relay(&mut self, relay_url: &str) {
+        tracing::info!("Disconnecting relay {} (no repos)", relay_url);
+        
+        self.relay_sync_index.write().await.remove(relay_url);
+        self.pending_sync_index.write().await.remove(relay_url);
+        
+        if let Some(conn) = self.connections.remove(relay_url) {
+            let _ = conn.client.disconnect().await;
+        }
+    }
+}
+```
+
+---
+
+## State Flow Summary
+
+```mermaid
+flowchart TB
+    subgraph Input
+        SS[SelfSubscriber]
+        OWN[Own Relay]
+    end
+    
+    subgraph RepoSyncIndex - What We Want
+        RSI[HashMap: Repo to Relays+Events]
+    end
+    
+    subgraph Derived Target
+        DT[derive_relay_targets fn]
+        TGT[Per-relay: repos + events we should sync]
+    end
+    
+    subgraph compute_actions - Decision Point
+        CA[Three-way diff: target - pending - confirmed]
+    end
+    
+    subgraph PendingSyncIndex - In Flight
+        PSI[Vec PendingBatch per relay]
+    end
+    
+    subgraph RelaySyncIndex - Confirmed State
+        RLI[RelayState per relay]
+        CONN[connection_status]
+        REPOS[repos + root_events]
+        TIMES[last_connected + disconnected_at]
+    end
+    
+    SS -->|subscribe| OWN
+    OWN -->|events| SS
+    SS -->|batch fires| RSI
+    RSI --> DT
+    DT --> TGT
+    TGT --> CA
+    PSI --> CA
+    RLI --> CA
+    CA -->|Layer 2+3 new items| AF[AddFilters]
+    AF -->|check filter count| CONSOL{count + new > 70?}
+    CONSOL -->|yes| CONSOLIDATE[consolidate]
+    CONSOLIDATE --> L1_CONSOL[build_announcement_filter with since]
+    L1_CONSOL --> L23_CONSOL[rebuild_layer2_and_layer3 with since]
+    CONSOL -->|no| SUB[subscribe]
+    AF -->|spawn if needed| CONN
+    SUB --> PSI
+    PSI -->|EOSE| REPOS
+    
+    CONN -->|disconnect| DISC[Clear PSI + set disconnected_at]
+    DISC -->|any reconnect| HC[handle_connect_or_reconnect]
+    
+    subgraph handle_connect_or_reconnect
+        HC --> FRESH_CHECK{is_fresh_sync?}
+        FRESH_CHECK -->|yes: no last_connected OR >15min| L1_FRESH[build_announcement_filter - no since]
+        FRESH_CHECK -->|no: quick reconnect| L1_QUICK[build_announcement_filter - with since]
+        L1_FRESH --> RCA1[recompute_actions_for_relay]
+        L1_QUICK --> L23_QUICK[rebuild_layer2_and_layer3 - with since]
+        L23_QUICK --> RCA2[recompute_actions_for_relay]
+    end
+```
+
+---
+
+## Key Design Decisions
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Startup mechanism | Self-subscription only | Single code path, fresh DB behaves same as reconnect |
+| Connect/reconnect handling | Unified handle_connect_or_reconnect | Single entry point for both initial and reconnect |
+| Layer 1 handling | Separate build_announcement_filter | Connection-level: subscribe ONCE on connect, NOT rebuilt in consolidation |
+| Layer 2+3 handling | Separate rebuild_layer2_and_layer3 | Item-level: managed by compute_actions, consolidated when filter count > 70 |
+| Filter functions | since as Option parameter | Allows same functions for fresh sync and catch-up |
+| Layer 2+3 tags | tagged_one_of_our_repo_event_filters, tagged_one_of_our_root_event_filters | Descriptive names, uses a/A/q for repos, e/E/q for events |
+| Since filter | Only on catch-up paths | Initial/stale gets full history, quick reconnect catches up |
+| compute_actions role | ONLY for new Layer 2+3 items | Does NOT handle Layer 1 or catch-up |
+| Catch-up pending tracking | No PendingBatch | Items already confirmed, don't need re-confirmation |
+| Consolidation trigger | On filter add, not periodic | Check in handle_add_filters before adding new filters |
+| Consolidation Layer 1 | Re-subscribe with since after unsubscribe_all | Maintains announcement stream |
+| Consolidation Layer 2+3 | rebuild_layer2_and_layer3 with since | Shared logic with quick_reconnect |
+| Clear on disconnect | Clear PSI on disconnect | Cleanup at event boundary, simpler than on reconnect |
+| 15-minute rule | Clear confirmed if disconnected >15min | Matches since filter buffer, prevents stale subscriptions |
+| Daily timer | Fresh sync (clears state) | Ensures consistency, detects drift |
+| Connection spawning | Via AddFilters handler | Single path for new relay discovery |
+| Self-subscriber reconnect | Use since-15min filter | Simpler than immediate RepoSyncIndex updates |
+
+---
+
+## Module Structure
+
+```
+src/sync/
+├── mod.rs              # SyncManager, main loop
+├── state.rs            # RepoSyncIndex, RelaySyncIndex, PendingSyncIndex types
+├── actions.rs          # AddFilters struct, compute_actions, build_filters
+├── self_subscriber.rs  # SelfSubscriber, batching logic
+├── relay_connection.rs # Per-relay WebSocket connection
+├── consolidation.rs    # Consolidation logic, daily timer
+├── health.rs           # Health tracking (reuse from v2)
+└── metrics.rs          # Prometheus metrics (reuse from v2)
+```
+
+---
+
+## Comparison: v3 vs v4
+
+| Aspect | v3 | v4 |
+|--------|----|----|
+| Connect handling | Separate initial vs reconnect | Unified handle_connect_or_reconnect |
+| Layer 1 handling | Mixed with other layers | Separate build_layer1_filter, always included |
+| Layer 2+3 tags | Basic a/e tags | Comprehensive a/A/q and e/E/q per v2 |
+| Rebuild logic | Duplicated in reconnect and consolidation | Shared rebuild_all_subscriptions method |
+| Consolidation trigger | Maybe periodic | On filter add in handle_add_filters |
+| Since filter application | Applied in handle_reconnect | build_all_filters with optional since |
+| PSI clearing | On disconnect | On disconnect (confirmed) |
+| Daily timer | Consolidation-style | Fresh sync (different from consolidation) |
+
+---
+
+## Self-Subscriber Flow
+
+The SelfSubscriber connects to the own relay and maintains a subscription to discover repos and events. It batches incoming events and triggers compute_actions.
+
+### State Tracking
+
+```rust
+pub struct SelfSubscriber {
+    own_relay_url: String,
+    relay_domain: String,
+    repo_sync_index: RepoSyncIndex,
+    pending_sync_index: PendingSyncIndex,
+    relay_sync_index: RelaySyncIndex,
+    action_tx: mpsc::Sender<AddFilters>,
+    /// Timestamp of last successful connection - used for since filter on reconnection
+    last_connected: Option<Timestamp>,
+    /// The active client connection
+    client: Option<Client>,
+}
+```
+
+### On Startup / Reconnect (Unified)
+
+Both initial startup and reconnection use the same `connect_and_subscribe` method:
+
+```rust
+impl SelfSubscriber {
+    async fn run(mut self) {
+        loop {
+            // Connect or reconnect
+            if let Err(e) = self.connect_and_subscribe().await {
+                tracing::warn!("Connection failed: {}, will retry", e);
+                tokio::time::sleep(Duration::from_secs(5)).await;
+                continue;
+            }
+            
+            // Run event loop until disconnection
+            self.event_loop().await;
+            
+            // Loop will retry connection
+        }
+    }
+    
+    async fn connect_and_subscribe(&mut self) -> Result<(), Error> {
+        let client = Client::new(Keys::generate());
+        client.add_relay(&self.own_relay_url).await?;
+        client.connect().await;
+        
+        // Build filter - add since only on reconnect
+        let filter = Filter::new().kinds([
+            Kind::Custom(30617),  // Repository announcements
+            Kind::GitPatch,       // 1617
+            Kind::Custom(1618),   // PRs  
+            Kind::Custom(1619),   // PR updates
+            Kind::GitIssue,       // 1621
+        ]);
+        
+        let filter = if let Some(ts) = self.last_connected {
+            // Reconnection: use since filter
+            let since = Timestamp::from(ts.as_u64().saturating_sub(900)); // -15 min buffer
+            filter.since(since)
+        } else {
+            // Initial connect: no since filter - get full history
+            filter
+        };
+        
+        // Update last_connected AFTER computing since
+        self.last_connected = Some(Timestamp::now());
+        
+        client.subscribe(filter, None).await?;
+        self.client = Some(client);
+        Ok(())
+    }
+}
+```
+
+### Event Loop with Batching
+
+```rust
+impl SelfSubscriber {
+    async fn event_loop(&mut self) {
+        let client = self.client.as_ref().unwrap();
+        let mut pending_events: Vec<Event> = Vec::new();
+        let mut batch_timer: Option<Instant> = None;
+        let batch_window = Duration::from_secs(5);
+        
+        loop {
+            let timeout = batch_timer
+                .map(|t| batch_window.saturating_sub(t.elapsed()))
+                .unwrap_or(Duration::from_secs(60));
+            
+            tokio::select! {
+                notification = client.notifications().recv() => {
+                    match notification {
+                        Ok(RelayPoolNotification::Event { event, .. }) => {
+                            pending_events.push(*event);
+                            
+                            // Start timer on first event - does NOT reset
+                            if batch_timer.is_none() {
+                                batch_timer = Some(Instant::now());
+                            }
+                        }
+                        Ok(RelayPoolNotification::Shutdown) => {
+                            // Connection lost
+                            break;
+                        }
+                        _ => {}
+                    }
+                }
+                _ = tokio::time::sleep(timeout), if batch_timer.is_some() => {
+                    // Batch window elapsed
+                    self.process_batch(pending_events.drain(..).collect()).await;
+                    batch_timer = None;
+                }
+            }
+        }
+    }
+    
+    async fn process_batch(&self, events: Vec<Event>) {
+        // 1. Update RepoSyncIndex
+        for event in events {
+            match event.kind.as_u16() {
+                30617 => self.handle_announcement(&event).await,
+                1617 | 1618 | 1619 | 1621 => self.handle_root_event(&event).await,
+                _ => {}
+            }
+        }
+        
+        // 2. Derive targets and compute actions
+        let repo_index = self.repo_sync_index.read().await;
+        let targets = derive_relay_targets(&repo_index);
+        
+        let pending = self.pending_sync_index.read().await;
+        let confirmed = self.relay_sync_index.read().await;
+        
+        let actions = compute_actions(&targets, &pending, &confirmed);
+        
+        drop(repo_index);
+        drop(pending);
+        drop(confirmed);
+        
+        // 3. Send actions to SyncManager
+        for action in actions {
+            let _ = self.action_tx.send(action).await;
+        }
+    }
+    
+    async fn handle_announcement(&self, event: &Event) {
+        // Extract repo_ref from event - 30617:pubkey:identifier
+        let d_tag = event.tags.iter()
+            .find_map(|tag| {
+                if tag.kind() == TagKind::D {
+                    tag.content().map(|s| s.to_string())
+                } else {
+                    None
+                }
+            })
+            .unwrap_or_default();
+        
+        let repo_ref = format!("30617:{}:{}", event.pubkey, d_tag);
+        
+        // Extract relay URLs from 'r' tags
+        let relays: HashSet<String> = event.tags.iter()
+            .filter_map(|tag| {
+                if tag.kind() == TagKind::Relay {
+                    tag.content().map(|s| s.to_string())
+                } else {
+                    None
+                }
+            })
+            .collect();
+        
+        // Update RepoSyncIndex
+        let mut index = self.repo_sync_index.write().await;
+        let needs = index.entry(repo_ref).or_default();
+        needs.relays = relays;
+    }
+    
+    async fn handle_root_event(&self, event: &Event) {
+        // Extract repo_ref from 'a' tag
+        let repo_ref = event.tags.iter()
+            .find_map(|tag| {
+                if tag.kind() == TagKind::A {
+                    tag.content().map(|s| s.to_string())
+                } else {
+                    None
+                }
+            });
+        
+        if let Some(repo_ref) = repo_ref {
+            let mut index = self.repo_sync_index.write().await;
+            let needs = index.entry(repo_ref).or_default();
+            needs.root_events.insert(event.id);
+        }
+    }
+}
+```
\ No newline at end of file
diff --git a/docs/explanation/state-structure-redesign-proposal.md b/docs/explanation/state-structure-redesign-proposal.md
new file mode 100644
index 0000000..0a27cf4
--- /dev/null
+++ b/docs/explanation/state-structure-redesign-proposal.md
@@ -0,0 +1,373 @@
+# State Structure Redesign Proposal v2
+
+## The Core Problem
+
+We need to transform:
+- **Repo Announcements** (30617) that list relays
+- **Root Events** (1617/1618/1619/1621) that tag repos
+
+Into:
+- **Per-relay subscriptions**: which repos and root events to sync from each relay
+
+And generate **RelayActions** when this mapping changes.
+
+---
+
+## Proposed Data Model
+
+### 1. RepoIndex (Primary Source of Truth)
+
+```rust
+/// Everything we know about repos we're tracking
+/// Key: repo addressable ref ("30617:pubkey:identifier")
+pub type RepoIndex = Arc<RwLock<HashMap<String, RepoInfo>>>;
+
+#[derive(Debug, Clone, Default)]
+pub struct RepoInfo {
+    /// Relay URLs listed in the repo's announcement
+    pub relays: HashSet<String>,
+    /// Root event IDs that reference this repo
+    pub root_events: HashSet<EventId>,
+}
+```
+
+**Updated by:** Database init, batch processing of new announcements/root events
+
+### 2. RelayIndex (Applied State)
+
+```rust
+/// What we've told each relay to sync
+/// Key: relay URL
+pub type RelayIndex = Arc<RwLock<HashMap<String, SyncTarget>>>;
+
+#[derive(Debug, Clone, Default, PartialEq)]
+pub struct SyncTarget {
+    /// Repos we're syncing for this relay
+    pub repos: HashSet<String>,
+    /// Root events we're tracking
+    pub root_events: HashSet<EventId>,
+}
+```
+
+**Updated by:** SyncManager after RelayActions are applied
+
+---
+
+## The Transformation
+
+```mermaid
+flowchart LR
+    subgraph Input
+        RA[Repo Announcements]
+        RE[Root Events]
+    end
+    
+    subgraph RepoIndex
+        R1[repo_a: relays=X,Y events=1,2]
+        R2[repo_b: relays=Y,Z events=3]
+    end
+    
+    subgraph Derived Target
+        T1[relay_X: repos=a events=1,2]
+        T2[relay_Y: repos=a,b events=1,2,3]
+        T3[relay_Z: repos=b events=3]
+    end
+    
+    subgraph RelayIndex Applied
+        A1[relay_X: repos=a events=1,2]
+        A2[relay_Y: repos=a events=1,2]
+    end
+    
+    RA --> R1
+    RA --> R2
+    RE --> R1
+    RE --> R2
+    
+    R1 --> T1
+    R1 --> T2
+    R2 --> T2
+    R2 --> T3
+```
+
+The **diff** between Derived Target and RelayIndex produces RelayActions:
+- relay_Y needs AddFilters for repo_b and event 3
+- relay_Z needs SpawnRelay
+
+---
+
+## Algorithm: derive_target_from_repo_index
+
+```rust
+/// Derive what we SHOULD be syncing from the repo data
+fn derive_relay_targets(repo_index: &HashMap<String, RepoInfo>) -> HashMap<String, SyncTarget> {
+    let mut targets: HashMap<String, SyncTarget> = HashMap::new();
+    
+    for (repo_ref, info) in repo_index {
+        // For each relay that lists this repo
+        for relay_url in &info.relays {
+            let target = targets.entry(relay_url.clone()).or_default();
+            target.repos.insert(repo_ref.clone());
+            target.root_events.extend(info.root_events.iter().cloned());
+        }
+    }
+    
+    targets
+}
+```
+
+---
+
+## Algorithm: process_batch
+
+```rust
+async fn process_batch(&self, pending: &mut PendingUpdates) {
+    // ============================================
+    // STEP 1: Update RepoIndex from batch
+    // ============================================
+    
+    let mut repo_index = self.repo_index.write().await;
+    
+    // 1a. Process root events - add to repo's root_events set
+    for event in pending.root_events.drain(..) {
+        for repo_ref in extract_repo_refs(&event) {
+            repo_index.entry(repo_ref)
+                .or_default()
+                .root_events
+                .insert(event.id);
+        }
+    }
+    
+    // 1b. Process announcements - update repo's relay set
+    for event in pending.announcements.drain(..) {
+        if !lists_our_service(&event) {
+            continue;
+        }
+        let repo_ref = build_repo_ref(&event);
+        let relay_urls: HashSet<String> = extract_relay_urls(&event)
+            .into_iter()
+            .filter(|url| !is_own_relay(url))
+            .collect();
+        
+        // Replace relay set (handles updates that change relays)
+        repo_index.entry(repo_ref)
+            .or_default()
+            .relays = relay_urls;
+    }
+    
+    // ============================================
+    // STEP 2: Derive target state from RepoIndex
+    // ============================================
+    
+    let target = derive_relay_targets(&repo_index);
+    drop(repo_index);  // Release write lock
+    
+    // ============================================
+    // STEP 3: Diff target vs applied (RelayIndex)
+    // ============================================
+    
+    let applied = self.relay_index.read().await;
+    let actions = compute_relay_actions(&target, &applied);
+    drop(applied);  // Release read lock
+    
+    // ============================================
+    // STEP 4: Send actions & update RelayIndex
+    // ============================================
+    
+    for action in actions {
+        match &action {
+            RelayAction::SpawnRelay { relay_url, repos_and_root_events } => {
+                // Update RelayIndex with new relay
+                let mut applied = self.relay_index.write().await;
+                applied.insert(relay_url.clone(), SyncTarget {
+                    repos: repos_and_root_events.keys().cloned().collect(),
+                    root_events: repos_and_root_events.values()
+                        .flat_map(|e| e.iter().cloned())
+                        .collect(),
+                });
+            }
+            RelayAction::AddFilters { relay_url, repos_and_new_root_event } => {
+                // Update RelayIndex with additions
+                let mut applied = self.relay_index.write().await;
+                if let Some(target) = applied.get_mut(relay_url) {
+                    for (repo, events) in repos_and_new_root_event {
+                        target.repos.insert(repo.clone());
+                        target.root_events.extend(events.iter().cloned());
+                    }
+                }
+            }
+        }
+        
+        // Send action to SyncManager
+        let _ = self.action_tx.send(action).await;
+    }
+}
+```
+
+---
+
+## Algorithm: compute_relay_actions
+
+```rust
+fn compute_relay_actions(
+    target: &HashMap<String, SyncTarget>,
+    applied: &HashMap<String, SyncTarget>,
+) -> Vec<RelayAction> {
+    let mut actions = Vec::new();
+    
+    for (relay_url, target_state) in target {
+        match applied.get(relay_url) {
+            None => {
+                // New relay - spawn it
+                let mut repos_and_events = HashMap::new();
+                for repo in &target_state.repos {
+                    // Get events for this specific repo
+                    let events = target_state.root_events.clone(); // simplified
+                    repos_and_events.insert(repo.clone(), events);
+                }
+                actions.push(RelayAction::SpawnRelay {
+                    relay_url: relay_url.clone(),
+                    repos_and_root_events: repos_and_events,
+                });
+            }
+            Some(applied_state) => {
+                // Existing relay - check for new repos/events
+                let new_repos: HashSet<_> = target_state.repos
+                    .difference(&applied_state.repos)
+                    .cloned()
+                    .collect();
+                let new_events: HashSet<_> = target_state.root_events
+                    .difference(&applied_state.root_events)
+                    .cloned()
+                    .collect();
+                
+                if !new_repos.is_empty() || !new_events.is_empty() {
+                    let mut repos_and_events = HashMap::new();
+                    for repo in &new_repos {
+                        repos_and_events.insert(repo.clone(), new_events.clone());
+                    }
+                    // Also handle new events for existing repos
+                    if !new_events.is_empty() && new_repos.is_empty() {
+                        for repo in &applied_state.repos {
+                            repos_and_events.insert(repo.clone(), new_events.clone());
+                        }
+                    }
+                    
+                    actions.push(RelayAction::AddFilters {
+                        relay_url: relay_url.clone(),
+                        repos_and_new_root_event: repos_and_events,
+                    });
+                }
+            }
+        }
+    }
+    
+    // Future: detect relay removal (in applied but not in target)
+    
+    actions
+}
+```
+
+---
+
+## Handling Announcement Updates
+
+When an announcement is **updated** and changes its relay list:
+
+```mermaid
+flowchart TD
+    A[repo_a announcement updated] --> B[Old: relays X,Y]
+    B --> C[New: relays Y,Z]
+    C --> D[RepoIndex updated: repo_a.relays = Y,Z]
+    D --> E[derive_relay_targets]
+    E --> F[Target: X=empty, Y=repo_a, Z=repo_a]
+    F --> G[Diff with Applied: X=repo_a, Y=repo_a]
+    G --> H1[X: repo_a removed - future RemoveFilters]
+    G --> H2[Z: new relay - SpawnRelay]
+```
+
+The current RelayAction types only support growth (SpawnRelay, AddFilters). Removal would need a new `RemoveFilters` action type - this is a future enhancement.
+
+---
+
+## Name Mappings
+
+| Current | Proposed | Semantics |
+|---------|----------|-----------|
+| `FollowingRepoRootEvents` | `RepoIndex` | Per-repo: relays + root events |
+| `SyncRelays` | `RelayIndex` | Per-relay: what we're syncing (applied state) |
+| - | `SyncTarget` | Struct for repos + events |
+| - | `RepoInfo` | Struct for relay set + event set |
+
+---
+
+## Data Flow Summary
+
+```mermaid
+flowchart TB
+    subgraph Batch Input
+        RA[30617 Announcements]
+        RE[Root Events 1617-1621]
+    end
+    
+    subgraph Step 1: Update Source
+        RI[RepoIndex]
+    end
+    
+    subgraph Step 2: Derive Target
+        DT[derive_relay_targets]
+        TGT[Target HashMap]
+    end
+    
+    subgraph Step 3: Diff
+        RLI[RelayIndex - Applied]
+        DIFF[compute_relay_actions]
+    end
+    
+    subgraph Step 4: Apply
+        ACT[RelayActions]
+        SM[SyncManager]
+    end
+    
+    RA --> RI
+    RE --> RI
+    RI --> DT
+    DT --> TGT
+    TGT --> DIFF
+    RLI --> DIFF
+    DIFF --> ACT
+    ACT --> SM
+    ACT --> |update| RLI
+```
+
+---
+
+## Files to Modify
+
+| File | Changes |
+|------|---------|
+| [`src/sync/mod.rs`](src/sync/mod.rs) | Replace type aliases with RepoIndex/RelayIndex + structs |
+| [`src/sync/self_subscriber.rs`](src/sync/self_subscriber.rs) | Rewrite process_batch with new algorithm |
+
+---
+
+## Questions for Approval
+
+1. **Naming**: Are `RepoIndex`/`RelayIndex` and `RepoInfo`/`SyncTarget` clear enough?
+
+2. **When to update RelayIndex**: Should we:
+   - (a) Update immediately when generating action (optimistic) ← proposed above
+   - (b) Update only after SyncManager confirms action succeeded
+
+3. **Bootstrap relay**: Keep special-casing it in RelayIndex (always present)?
+
+4. **Future work**: Add `RemoveFilters` action for relay removal, or defer?
+
+---
+
+## Benefits
+
+1. **Logical flow**: Source → Derived → Diff → Actions
+2. **Single source of truth**: RepoIndex is the authoritative data
+3. **Clear transformation**: `derive_relay_targets()` is a pure function
+4. **Handles updates**: Replacing `repo.relays` naturally handles announcement changes
+5. **Testable**: Each step can be unit tested independently
\ No newline at end of file