Clarify MCE semantics and enhance MRD description

Added clarification on MCE's request-response semantics and expanded on MRD's support for push-based propagation.

Author: kagvi13

docs/HMP-0005.md

@@ -1514,6 +1514,10 @@ For details and examples, see **section 3.15** — *Usage of `network` and `broa
 The **Mesh Container Exchange (MCE)** mechanism is designed for discovering, requesting, and exchanging containers between agents in a distributed network.  
 It provides **container synchronization without duplication** while considering network constraints (`broadcast`, `network`).
 
+*MCE does not mandate request-response semantics.*
+
+---
+
 ### 5.1 General principles
 
 1. Each agent maintains a **Container Index** — a set of minimal metadata describing which containers are available in its storage and how they are cognitively positioned.  
@@ -4727,12 +4731,18 @@ and lists all containers with their metadata and hashes.
 
 The **Message Routing & Delivery (MRD)** subsystem defines how containers are delivered to specific agents across the Mesh.  
 Unlike the **Mesh Container Exchange (MCE)**, which is responsible for publishing and exchanging containers in the Mesh network,  
-MRD focuses on *directed delivery* — ensuring that a container eventually reaches its intended recipient,  
-even through NAT, intermittent connectivity, or indirect relay paths.
+MRD focuses on *directed delivery* — ensuring that a container eventually reaches its intended recipient, even through NAT, intermittent connectivity, or indirect relay paths.
 
 In HMP v5.0, message delivery is performed through verifiable **container transactions**.  
 Peers discover suitable relays via `peer_announce` metadata, while delivery routes are auditable through appended `relay_chain` entries and distributed container publication in `container_index` records.
 
+MRD **MAY support push-based propagation** (unsolicited or role-driven container dissemination), including:
+
+  * role-based dissemination;
+  * pub/sub hubs;
+  * archival store-and-forward nodes;
+  * opportunistic broadcast channels.
+
 ---
 
 #### 6.8.1 Purpose
@@ -4897,8 +4907,10 @@ flowchart LR
 
 > **Summary:**
 > MRD provides a verifiable, role-driven message delivery layer above MCE.
-> It ensures containers can reach intended recipients through trusted relays,
-> maintaining auditability, TTL enforcement, and reputation-aware routing policies.
+> It ensures containers can reach intended recipients through trusted relays, maintaining auditability, TTL enforcement, and reputation-aware routing policies.
+>
+> **MCE defines container exchange primitives, not delivery strategies.
+> MRD defines how, when, and to whom containers are propagated.**
 
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