diff --git a/CLAUDE.md b/CLAUDE.md
index 021b1ea..cc5c009 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -16,6 +16,7 @@ Regel: Keine Datei in legacy/ wird verändert. Nur lesen.
 ## Regeln
 @rules/framework-constraints.md
 @rules/session-protocol.md
+@rules/parallel-agents.md
 
 ## Aktiver Scope
 Aktuelle Phase: 1 — Discovery
diff --git a/rules/parallel-agents.md b/rules/parallel-agents.md
new file mode 100644
index 0000000..b3e7616
--- /dev/null
+++ b/rules/parallel-agents.md
@@ -0,0 +1,5 @@
+- Subagents only write to their own output file — never to shared state
+- Shared state files (status.md, decisions-log.md, task.md) are only written by the main orchestrating agent
+- Each Definition-of-Done item in task.md must produce its own independent output file
+- When dispatching parallel agents: assign each agent exactly one output file and pass the relevant legacy source paths
+- After all subagents complete: the main agent consolidates results into status.md and decisions-log.md