@@ -5,6 +5,22 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.2.1] - 2026-03-12
+
+### Fixed
+
+- Child tracking race condition: use Registry fallback when injected children lag state updates, and deduplicate spawn_child results to keep tracking consistent under async races.
+- Dashboard cost refresh storm: debounce `cost_recorded` PubSub events (2s window) to prevent O(N²) re-query feedback loop that caused UI lockup with 100+ agents.
+
+### Changed
+
+- Removed 20-child injection limit that caused agents to lose visibility of children beyond 20, triggering unbounded respawning.
+- Deferred per-agent GenServer calls (todos, budget) in Dashboard to after mount to prevent longpoll timeout with many live agents.
+
+### Removed
+
+- Dead `registry_spawned_at/1` function and unreachable code paths in ChildrenInjector.
+
 ## [0.2.0] - 2026-03-10
 
 ### Added
 
@@ -28,7 +28,7 @@
 - ConsensusHandler.Helpers: Helper functions (133 lines), normalize_sibling_context/1, self_contained_actions/0, has_pending_self_contained?/1 (v26.0), coerce_wait_value/1 (v34.0 DRY extraction), prepend_to_content/2, extract_shell_check_id/2 (v25.0 shared helper for shell routing), primary_skill_name/1 (REFACTOR DRY extraction from ActionExecutor)
 - ConsensusHandler.LogHelper: Logging helpers (63 lines), safe_broadcast_log/5, log_action_error/1 (v28.0: {:error, _} unwrap, {:action_crashed, tuple} clause, extended @warning_errors with transient network errors)
 - ConsensusHandler.TodoInjector: TODO injection (82 lines), inject_todo_context/2, format_todos_as_xml/1, escape_xml/1
-- ConsensusHandler.ChildrenInjector: Children context injection (150 lines), inject_children_context/2, format_children/1, Registry-based status check, v2.0: enrich_with_messages/2 cross-references state.messages for latest_message + latest_message_at per child
+- ConsensusHandler.ChildrenInjector: Children context injection (218 lines), inject_children_context/2, format_children/1, Registry-based status check, v2.0: enrich_with_messages/2 cross-references state.messages for latest_message + latest_message_at per child, v3.0: Registry fallback discovers children via Registry.select when state.children is empty/incomplete (race condition fix)
 - ConsensusHandler.AceInjector: ACE context injection (82 lines, v1.0), inject_ace_context/3 into FIRST user message (historical knowledge), format_ace_context/2
 - ConsensusHandler.ContextInjector: Context token injection (95 lines, v2.0), inject_context_tokens/1 counts fully-built messages (excluding system prompt), format_context_tokens/1 with comma separators
 - StateUtils: State manipulation helpers (145 lines), action_type tracking for NO_EXECUTE, v3.0 adds merge_consensus_state/2 for ACE state merging (extracted from MessageHandler/ConsensusContinuationHandler), v5.0 adds cancel_wait_timer/1 for DRY timer cancellation (4 pattern-matched clauses), v6.0 adds schedule_consensus_continuation/1 for DRY "set flag + send trigger" pattern, v38.0 adds :cached_system_prompt to merge_keys
@@ -80,13 +80,14 @@
 
 ## Children Tracking (2025-12-27)
 - Core.State.children: `[%{agent_id: String.t(), spawned_at: DateTime.t()}]` (changed from `[pid()]`)
-- Core.ChildrenTracker: handle_child_spawned/2 (prepend), handle_child_dismissed/2 (remove by id), handle_child_restored/2 (restoration)
+- Core.ChildrenTracker: handle_child_spawned/2 (idempotent prepend), handle_child_dismissed/2 (remove by id), handle_child_restored/2 (restoration)
 - ConsensusHandler.ChildrenInjector: inject_children_context/2 (up to 20 children, Registry-filtered)
 - Spawn action: Casts `{:child_spawned, %{agent_id, spawned_at}}` to parent after success
 - DismissChild action: Casts `{:child_dismissed, child_id}` to parent after dispatch
 - XML format: `<children>{"agent_id":"...", "spawned_at":"...", "latest_message":"...", "latest_message_at":"..."}</children>` (v2.0: enriched with message preview)
 - Injection order: children→todos→content (children prepended last, appears first)
 - v2.0 enrichment: Cross-references state.messages at injection time, truncates latest_message to 100 chars, RFC 2822 timestamps
+- v3.0 Registry fallback: ChildrenInjector discovers children via Registry.select when state.children is empty/incomplete (batch_async race condition fix). Dual-path tracking contract: both ChildrenTracker.handle_child_spawned/2 and ActionResultHandler.maybe_track_child/3 enforce Enum.any? idempotency guards
 
 ## Patterns
 - Full dependency injection (registry/dynsup/pubsub via opts)
 
@@ -5,7 +5,7 @@
 - Helpers: Shared helper functions (116 lines), self_contained_actions/0, has_pending_self_contained?/1 (v26.0), coerce_wait_value/1, extract_shell_check_id/2, normalize_sibling_context/1
 - LogHelper: Logging helpers (63 lines), safe_broadcast_log/5, log_action_error/1 (v28.0: {:error, _} unwrap, {:action_crashed, tuple} clause, extended @warning_errors)
 - TodoInjector: Todo list context injection (82 lines), inject_todo_context/2
-- ChildrenInjector: Children context injection (150 lines), inject_children_context/2, format_children/1, v2.0: enrich_with_messages/2 cross-references state.messages to add latest_message + latest_message_at per child
+- ChildrenInjector: Children context injection (218 lines), inject_children_context/2, format_children/1, v2.0: enrich_with_messages/2 cross-references state.messages to add latest_message + latest_message_at per child, v3.0: Registry fallback via discover_registry_children/2 + safe_find_children_by_parent/2 + build_registry_child/1 + merge_registry_children/2 for race condition fix
 - AceInjector: ACE context injection (82 lines), inject_ace_context/3
 - CorrectionInjector: Per-model correction feedback injection (56 lines, v1.0), inject_correction_feedback/3 — prepends correction to last user message at MessageBuilder step 7.5
 - ContextInjector: Context token injection (95 lines), inject_context_tokens/1
 
@@ -1,32 +1,38 @@
 defmodule Quoracle.Agent.ConsensusHandler.ChildrenInjector do
   @moduledoc """
-  Handles children injection into consensus messages.
-  Extracted from ConsensusHandler to maintain <500 line modules.
+  Injects children context into consensus messages as a `<children>` XML block.
 
-  v2.0: Message enrichment — cross-references state.messages to show
-  latest_message_preview and latest_message_at per child in consensus context.
+  Discovers children from two sources: `state.children` (tracked via casts) and
+  Registry (fallback for race conditions where casts haven't arrived yet). Merges
+  both sources, filters to live children, enriches each with the latest inbox
+  message preview, and prepends the block to the last consensus message.
   """
 
   alias Quoracle.Agent.ConsensusHandler.Helpers
 
   @max_message_length 100
 
-  @doc "Injects children context (up to 20) into last message. Returns messages unchanged only if messages empty."
+  @doc "Injects children context into last message. Returns messages unchanged only if messages empty."
   @spec inject_children_context(map(), list(map())) :: list(map())
   def inject_children_context(state, messages) do
     if messages == [], do: messages, else: inject_children_block(state, messages)
   end
 
   defp inject_children_block(state, messages) do
-    children = Map.get(state, :children, [])
     registry = Map.get(state, :registry)
-    live_children = if children == [], do: [], else: filter_live_children(children, registry)
+    registry_children = discover_registry_children(state, registry)
+
+    live_children =
+      state
+      |> Map.get(:children, [])
+      |> filter_live_children(registry)
+      |> merge_registry_children(registry_children)
 
     if live_children == [] do
       inject_empty_children(messages)
     else
       inbox = Map.get(state, :messages, [])
-      enriched = enrich_with_messages(Enum.take(live_children, 20), inbox)
+      enriched = enrich_with_messages(live_children, inbox)
       inject_into_last_message(messages, enriched)
     end
   end
@@ -93,6 +99,61 @@ defmodule Quoracle.Agent.ConsensusHandler.ChildrenInjector do
     end
   end
 
+  @spec discover_registry_children(map(), atom() | pid() | nil) :: list(map())
+  defp discover_registry_children(%{agent_id: nil}, _registry), do: []
+  defp discover_registry_children(_state, nil), do: []
+
+  defp discover_registry_children(state, registry) do
+    case Map.get(state, :agent_id) do
+      nil ->
+        []
+
+      agent_id ->
+        case safe_registry_lookup(registry, agent_id) do
+          {:ok, parent_pid} ->
+            registry
+            |> safe_find_children_by_parent(parent_pid)
+            |> Enum.map(&build_registry_child/1)
+
+          :not_found ->
+            []
+        end
+    end
+  end
+
+  @spec safe_find_children_by_parent(atom() | pid(), pid()) :: list({String.t(), map()})
+  defp safe_find_children_by_parent(registry, parent_pid) do
+    try do
+      Registry.select(registry, [
+        {{{:agent, :"$1"}, :"$2", :"$3"}, [{:==, {:map_get, :parent_pid, :"$3"}, parent_pid}],
+         [{{:"$1", :"$3"}}]}
+      ])
+    rescue
+      _ -> []
+    catch
+      _, _ -> []
+    end
+  end
+
+  # Registry composite is a map with keys :pid, :agent_id, :task_id, :parent_pid,
+  # :parent_id, :registered_at — but NOT :spawned_at or :budget_allocated,
+  # so we use approximate values for the child entry.
+  @spec build_registry_child({String.t(), map()}) :: map()
+  defp build_registry_child({agent_id, _composite}) do
+    %{
+      agent_id: agent_id,
+      spawned_at: DateTime.utc_now(),
+      budget_allocated: nil
+    }
+  end
+
+  @spec merge_registry_children(list(map()), list(map())) :: list(map())
+  defp merge_registry_children(children, registry_children) do
+    tracked_ids = MapSet.new(children, & &1.agent_id)
+
+    children ++ Enum.reject(registry_children, &MapSet.member?(tracked_ids, &1.agent_id))
+  end
+
   # Enrich children with latest message data from the agent's inbox.
   # Cross-references each child's agent_id against inbox messages to find
   # the most recent message (by timestamp) from that child.
 
@@ -10,7 +10,7 @@
 - format_sender_id/1: :parent→"parent", :user→"user", binary→as-is
 
 ## Private Helpers
-- maybe_track_child/3: Track spawned children from non-blocking dispatch results (spawn_child action only)
+- maybe_track_child/3: Track spawned children from non-blocking dispatch results (spawn_child action only), v30.0: Enum.any? idempotency guard prevents duplicate entries (matches ChildrenTracker.handle_child_spawned/2 pattern)
 - maybe_update_budget_committed/3: Update budget_data.committed for spawn_child results (replaces removed Core.update_budget_committed callback)
 - maybe_track_shell_router/3: Populate shell_routers with {command_id, router_pid} from async shell Phase 1 results (v25.0, v26.0 refactor: uses shared `async_shell_phase1?/1` predicate). Matches `{:ok, %{status: :running, command_id: binary, sync: false}}`.
 - async_shell_phase1?/1: Shared predicate detecting async shell Phase 1 ack. Used by both pending_actions guard and shell_routers tracking. Pattern: `{:ok, %{status: :running, command_id: binary, sync: false}}`.
 
@@ -194,22 +194,28 @@ defmodule Quoracle.Agent.MessageHandler.ActionResultHandler do
        when is_map(child_result) do
     if Keyword.get(opts, :action_atom) == :spawn_child and
          Map.has_key?(child_result, :agent_id) do
-      child_data = %{
-        agent_id: child_result.agent_id,
-        spawned_at: Map.get(child_result, :spawned_at, DateTime.utc_now()),
-        budget_allocated: Map.get(child_result, :budget_allocated)
-      }
+      child_id = child_result.agent_id
+      children = Map.get(state, :children, [])
 
-      Map.update(state, :children, [child_data], &[child_data | &1])
+      if Enum.any?(children, &(&1.agent_id == child_id)) do
+        state
+      else
+        child_data = %{
+          agent_id: child_id,
+          spawned_at: Map.get(child_result, :spawned_at, DateTime.utc_now()),
+          budget_allocated: Map.get(child_result, :budget_allocated)
+        }
+
+        Map.update(state, :children, [child_data], &[child_data | &1])
+      end
     else
       state
     end
   end
 
   defp maybe_track_child(state, _result, _opts), do: state
 
-  # v35.0 R67: Update budget_committed when spawn_child result includes budget_allocated
-  # Replaces the removed Core.update_budget_committed callback from Spawn (FIX_BudgetCallbackElimination)
+  # v35.0 R67: Update committed budget from successful spawn_child results
   defp maybe_update_budget_committed(state, {:ok, child_result}, opts)
        when is_map(child_result) do
     if Keyword.get(opts, :action_atom) == :spawn_child do