diff --git a/docs/solution-design.md b/docs/solution-design.md
index cc57b35..fb0ffd7 100644
--- a/docs/solution-design.md
+++ b/docs/solution-design.md
@@ -4,6 +4,7 @@
 **Date**: 2026-05-22  
 **Status**: Active  
 **Ground Truth**: [`src/msghandler.jl`](../src/msghandler.jl)
+**ASG Framework Alignment**: v8 pillars - Requirements → Solution Design → Specification → Walkthrough → Implementation Plan → Validation → Runbook
 
 ---
 
@@ -11,16 +12,16 @@
 
 msghandler addresses the challenge of cross-platform data exchange between **Julia**, **JavaScript**, **Python**, **Dart**, **Rust**, and **MicroPython** applications using message brokers as transport layers.
 
-### Problem Statement
+### User Problems
 
-Developers working across multiple programming languages face significant obstacles when trying to share data:
-
-| Problem | Description | User Impact |
-|---------|-------------|-------------|
-| **P-001**: Cross-platform data serialization | Different languages have incompatible data types and serialization formats | Developers must write platform-specific conversion code |
-| **P-002**: Large payload handling | Message brokers have size limits, but large files need to be transferred | Large files either fail or require complex workarounds |
-| **P-003**: Transport abstraction | Each platform has different message broker libraries and APIs | No unified interface across platforms |
-| **P-004**: Request-response patterns | Bi-directional communication requires complex correlation tracking | Developers must implement custom message routing |
+| Problem | Description | User Impact | Requirement ID |
+|---------|-------------|-------------|----------------|
+| **P-001**: Cross-platform data serialization | Different languages have incompatible data types and serialization formats | Developers must write platform-specific conversion code | FR-001, FR-002 |
+| **P-002**: Large payload handling | Message brokers have size limits, but large files need to be transferred | Large files either fail or require complex workarounds | FR-003 |
+| **P-003**: Transport abstraction | Each platform has different message broker libraries and APIs | No unified interface across platforms | FR-013, FR-014 |
+| **P-004**: Request-response patterns | Bi-directional communication requires complex correlation tracking | Developers must implement custom message routing | FR-011 |
+| **P-005**: File server reliability | File server may be temporarily unavailable during downloads | Failed downloads without retry mechanism | FR-010 |
+| **P-006**: Payload type preservation | Different platforms have different type systems | Data corruption or misinterpretation on receiving end | FR-006, FR-007 |
 
 ### Solution Boundaries
 
@@ -30,6 +31,7 @@ Developers working across multiple programming languages face significant obstac
 - File server integration using Claim-Check pattern
 - Multi-payload support with mixed types in single message
 - Exponential backoff for reliable file downloads
+- Correlation ID propagation for message tracing
 
 **Out of Scope**:
 - Message compression (adds complexity without clear benefit)
@@ -39,14 +41,16 @@ Developers working across multiple programming languages face significant obstac
 
 ### Decision IDs
 
-| Decision ID | Decision | Description |
-|-------------|----------|-------------|
-| SD-001 | Claim-Check Pattern | Large payloads uploaded to HTTP server, small payloads sent directly |
-| SD-002 | Automatic Transport Selection | <0.5MB = direct, ≥0.5MB = link based on size threshold |
-| SD-003 | Handler Function Abstraction | Pluggable file server implementations via handler functions |
-| SD-004 | Unified Tuple Format | Same `(dataname, data, type)` format across all platforms |
-| SD-005 | Base64 Encoding | JSON-compatible binary data transport |
-| SD-006 | Transport Abstraction | Support multiple broker protocols (NATS/MQTT/WebSocket) transparently |
+| Decision ID | Decision | Description | Requirement IDs | NFR IDs |
+|-------------|----------|-------------|-----------------|---------|
+| SD-001 | Claim-Check Pattern | Large payloads uploaded to HTTP server, small payloads sent directly | FR-003, FR-004 | NFR-104, NFR-105 |
+| SD-002 | Automatic Transport Selection | <0.5MB = direct, ≥0.5MB = link based on size threshold | FR-003, FR-004 | NFR-104, NFR-105 |
+| SD-003 | Handler Function Abstraction | Pluggable file server implementations via handler functions | FR-008, FR-009 | NFR-202 |
+| SD-004 | Unified Tuple Format | Same `(dataname, data, type)` format across all platforms | FR-006, FR-007 | - |
+| SD-005 | Base64 Encoding | JSON-compatible binary data transport | FR-012 | - |
+| SD-006 | Transport Abstraction | Support multiple broker protocols (NATS/MQTT/WebSocket) transparently | FR-013, FR-014 | NFR-201 |
+| SD-007 | Exponential Backoff | Retry failed file downloads with exponential backoff | FR-010 | NFR-202 |
+| SD-008 | Correlation ID Propagation | Propagate correlation IDs through all message processing steps | FR-011 | NFR-401, NFR-403 |
 
 ---
 
@@ -77,6 +81,8 @@ Sender (smartpack)              Transport Layer              Receiver (smartunpa
 | **SD-004** | Unified Tuple Format | Same input/output format across all platforms | Platform-native formats - no interoperability; Protocol buffers - too heavy |
 | **SD-005** | Base64 Encoding | JSON-compatible binary data transport | Raw bytes - not JSON-compatible; Hex encoding - 2x size overhead |
 | **SD-006** | Transport Abstraction | Support multiple broker protocols (NATS/MQTT/WebSocket) transparently | Platform-specific libraries - no interoperability |
+| **SD-007** | Exponential Backoff | Retry failed file downloads with exponential backoff | Simple retry - too aggressive; No retry - poor reliability |
+| **SD-008** | Correlation ID Propagation | Propagate correlation IDs through all message processing steps | Manual correlation - error-prone; No tracing - debug impossible |
 
 ### Architecture Components
 
@@ -110,7 +116,7 @@ flowchart TB
         DOWNLOAD -.->|Fetch URL| API
     end
     
-    style CLIENT fill:#e1f5fe,stroke:#0288d1,stroke-width:2px
+    style Client fill:#e1f5fe,stroke:#0288d1,stroke-width:2px
     style Transport fill:#ffe0b2,stroke:#f57c00,stroke-width:2px
     style FileServer fill:#c8e6c9,stroke:#43a047,stroke-width:2px
 ```
@@ -190,8 +196,8 @@ flowchart TD
 | Component | Responsibilities | Decision IDs | Requirements Addressed |
 |-----------|-----------------|--------------|----------------------|
 | **Serialization Layer** | Convert data types to transport format (Base64/URL) | SD-005 | FR-001, FR-002, FR-012 |
-| **Envelope Builder** | Create standardized message envelope with metadata | SD-001 | FR-011, FR-013, FR-014 |
-| **Handler Functions** | Abstract file server operations for pluggability | SD-003 | FR-008, FR-009 |
+| **Envelope Builder** | Create standardized message envelope with metadata | SD-001, SD-008 | FR-011, FR-013, FR-014 |
+| **Handler Functions** | Abstract file server operations for pluggability | SD-003, SD-007 | FR-008, FR-009, FR-010 |
 | **Transport Adapter** | Support multiple broker protocols transparently | SD-006 | FR-013, FR-014 |
 | **Payload Manager** | Track payload types, sizes, and encoding | SD-004 | FR-006, FR-007 |
 
@@ -201,7 +207,8 @@ flowchart TD
 
 ### SD-001: Why Claim-Check Pattern?
 
-**Requirement**: FR-003 - Large file handling, FR-004 - Direct transport for small payloads
+**Requirement**: FR-003 (Large file handling), FR-004 (Direct transport for small payloads)
+**NFRs**: NFR-104 (File upload latency <1s), NFR-105 (File download latency <1s)
 
 **Rationale**:
 - Transport layers (NATS, MQTT) have message size limits (typically 1MB)
@@ -211,7 +218,8 @@ flowchart TD
 
 ### SD-002: Why Handler Functions for File Server?
 
-**Requirement**: FR-008 - Plik integration, FR-009 - Custom file server support
+**Requirement**: FR-008 (Plik integration), FR-009 (Custom file server support)
+**NFR**: NFR-202 (File server availability <5% failure rate)
 
 **Rationale**:
 - Plik is common open-source solution for file server
@@ -221,7 +229,7 @@ flowchart TD
 
 ### SD-003: Why Tuple Format for Payloads?
 
-**Requirement**: FR-006 - Multi-payload messages, FR-007 - Payload type preservation
+**Requirement**: FR-006 (Multi-payload messages), FR-007 (Payload type preservation)
 
 **Rationale**:
 - `(dataname, data, type)` tuple is language-agnostic
@@ -231,7 +239,7 @@ flowchart TD
 
 ### SD-004: Why Base64 Encoding?
 
-**Requirement**: FR-012 - Message serialization, FR-001 - Cross-platform text messaging
+**Requirement**: FR-012 (Message serialization), FR-001 (Cross-platform text messaging)
 
 **Rationale**:
 - JSON is universal - works on all platforms
@@ -241,7 +249,8 @@ flowchart TD
 
 ### SD-005: Why Automatic Transport Selection?
 
-**Requirement**: FR-003, FR-004, NFR-104, NFR-105
+**Requirement**: FR-003 (Large file handling), FR-004 (Direct transport for small payloads)
+**NFRs**: NFR-104 (File upload latency <1s), NFR-105 (File download latency <1s)
 
 **Rationale**:
 - <0.5MB payloads use direct transport (<1s latency, FR-004 KPI)
@@ -250,7 +259,8 @@ flowchart TD
 
 ### SD-006: Why Transport Abstraction?
 
-**Requirement**: FR-013, FR-014, NFR-201
+**Requirement**: FR-013 (Transport publishing), FR-014 (Transport subscription)
+**NFR**: NFR-201 (Message delivery at-least-once)
 
 **Rationale**:
 - Support multiple broker protocols (NATS, MQTT, WebSocket) transparently
@@ -258,17 +268,40 @@ flowchart TD
 - Unified API across all platforms
 - At-least-once delivery semantics via transport layer
 
+### SD-007: Why Exponential Backoff?
+
+**Requirement**: FR-010 (Exponential backoff retry)
+**NFR**: NFR-202 (File server availability <5% failure rate)
+
+**Rationale**:
+- File server may be temporarily unavailable
+- Exponential backoff prevents overwhelming server during outages
+- Default: 5 retries, 100ms base delay, 5000ms max delay
+- 95% successful downloads within retry limit (FR-010 KPI)
+
+### SD-008: Why Correlation ID Propagation?
+
+**Requirement**: FR-011 (Correlation ID propagation)
+**NFRs**: NFR-401 (Required logs), NFR-403 (Tracing)
+
+**Rationale**:
+- Trace messages across distributed systems
+- Correlation ID logged with every message (NFR-401)
+- Propagated through all message processing steps (NFR-403)
+- Enables debugging and performance analysis in production
+
 ---
 
 ## 6. Risk Assessment
 
-| Risk | Impact | Probability | Mitigation |
-|------|--------|-------------|------------|
-| **Performance degradation with >500KB payloads** | High | Medium | Size threshold detection; Link transport fallback |
-| **File server availability issues** | Medium | Low | Exponential backoff retry; Graceful degradation |
-| **Platform-specific bugs** | Medium | Low | Comprehensive test suite per platform; CI validation |
-| **Encoding mismatches between platforms** | High | Low | Strict specification; Test contracts; Validation rules |
-| **Transport layer incompatibility** | Medium | Low | Transport-agnostic design; Handler abstraction |
+| Risk | Impact | Probability | Mitigation | Requirement IDs | NFR IDs |
+|------|--------|-------------|------------|-----------------|---------|
+| **Performance degradation with >500KB payloads** | High | Medium | Size threshold detection; Link transport fallback | FR-003, FR-004 | NFR-104, NFR-105 |
+| **File server availability issues** | Medium | Low | Exponential backoff retry; Graceful degradation | FR-010 | NFR-202 |
+| **Platform-specific bugs** | Medium | Low | Comprehensive test suite per platform; CI validation | FR-001, FR-002, FR-006, FR-007 | - |
+| **Encoding mismatches between platforms** | High | Low | Strict specification; Test contracts; Validation rules | FR-012 | NFR-301 |
+| **Transport layer incompatibility** | Medium | Low | Transport-agnostic design; Handler abstraction | FR-013, FR-014 | NFR-201 |
+| **Correlation ID loss in processing** | Medium | Low | Centralized trace context management | FR-011 | NFR-401, NFR-403 |
 
 ---
 
@@ -276,13 +309,13 @@ flowchart TD
 
 | Solution Component | Decision ID | Requirement ID | Description |
 |-------------------|-------------|----------------|-------------|
-| **smartpack() function** | SD-001, SD-002, SD-004, SD-005, SD-006 | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Unified API for sending messages across all platforms |
-| **smartunpack() function** | SD-001, SD-002, SD-004, SD-005, SD-006 | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Unified API for receiving messages across all platforms |
-| **Direct transport** | SD-002 | FR-004, NFR-101, NFR-102, NFR-104, NFR-105 | Send payloads < threshold directly via transport |
-| **Link transport** | SD-001, SD-002 | FR-003, NFR-104, NFR-105 | Upload payloads ≥ threshold to file server |
-| **File server handler** | SD-003 | FR-008, FR-009, FR-010 | Pluggable upload/download handlers with retry logic |
+| **smartpack() function** | SD-001, SD-002, SD-004, SD-005, SD-006, SD-008 | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Unified API for sending messages across all platforms |
+| **smartunpack() function** | SD-001, SD-002, SD-004, SD-005, SD-006, SD-007, SD-008 | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Unified API for receiving messages across all platforms |
+| **Direct transport** | SD-002 | FR-004 | Send payloads < threshold directly via transport |
+| **Link transport** | SD-001, SD-002 | FR-003 | Upload payloads ≥ threshold to file server |
+| **File server handler** | SD-003, SD-007 | FR-008, FR-009, FR-010 | Pluggable upload/download handlers with retry logic |
 | **Payload type preservation** | SD-004 | FR-006, FR-007 | Support text, dictionary, arrowtable, jsontable, image, audio, video, binary |
-| **Correlation ID** | SD-001 | FR-011, NFR-401, NFR-403 | Message tracing across distributed systems |
+| **Correlation ID propagation** | SD-008 | FR-011 | Message tracing across distributed systems |
 | **Multi-payload support** | SD-004 | FR-006, FR-007 | List of (dataname, data, type) tuples |
 
 ### Non-Functional Requirements Traceability
@@ -295,11 +328,15 @@ flowchart TD
 | **Concurrent connections** | SD-006 | NFR-106 | Support 100+ simultaneous connections |
 | **Message throughput** | SD-005, SD-006 | NFR-107 | Handle 1000+ messages/second per instance |
 | **At-least-once delivery** | SD-006 | NFR-201 | Transport layer semantics |
-| **Graceful degradation** | SD-003 | NFR-202 | File server unavailability handling |
+| **Graceful degradation** | SD-003, SD-007 | NFR-202 | File server unavailability handling |
 | **Auto-reconnect** | SD-006 | NFR-203 | Transport connection failure recovery |
-| **Required logs** | SD-001 | NFR-401 | Correlation ID, msg_id, timestamp, etc. |
+| **Payload integrity** | SD-005 | NFR-301 | 100% SHA-256 checksum validation |
+| **Transport security** | SD-006 | NFR-302 | 100% TLS connections in production |
+| **File server security** | SD-003 | NFR-303 | 100% authenticated file uploads |
+| **Required logs** | SD-001, SD-008 | NFR-401 | Correlation ID, msg_id, timestamp, etc. |
 | **Critical metrics** | SD-001, SD-005 | NFR-402 | messages_sent_total, file upload/download duration |
-| **Tracing** | SD-001 | NFR-403 | Correlation ID propagation |
+| **Tracing** | SD-001, SD-008 | NFR-403 | Correlation ID propagation |
+| **Alerting** | SD-007 | NFR-404 | <5min alert latency for `download_retry_exceeded` |
 
 ---
 
@@ -307,24 +344,33 @@ flowchart TD
 
 | Stage Transition | Gap-Check Question | Status |
 |------------------|-------------------|--------|
-| **Requirements → Solution Design** | Does the Solution Design clearly explain how the system solves the user problem, not just what it does? | ✅ Verified - All user stories mapped to solution components with requirement ID and decision ID references |
+| **Requirements → Solution Design** | Does the Solution Design clearly explain how the system solves the user problem, not just what it does? | ✅ Verified - All user problems mapped to solution components with requirement ID and decision ID references |
 | **Solution Design → Specification** | Does the Specification define all technical details that the solution approach requires? | ⏳ Pending - Specification needs review for completeness |
 | **Solution Design → Walkthrough** | Does the Walkthrough reflect the complete flow including error states and timing? | ⏳ Pending - Walkthrough needs validation against design |
 
 ### Solution Design Validation
 
-**Problem**: Users need to send mixed payload types (text + image + large file) between Julia, JavaScript, Python, and MicroPython applications.
+**User Problems** (from requirements.md):
+- **P-001**: Cross-platform data serialization (FR-001, FR-002)
+- **P-002**: Large payload handling (FR-003)
+- **P-003**: Transport abstraction (FR-013, FR-014)
+- **P-004**: Request-response patterns (FR-011)
+- **P-005**: File server reliability (FR-010)
+- **P-006**: Payload type preservation (FR-006, FR-007)
 
 **Solution Components**:
-1. **SD-001** - `smartpack()` - Unified API for all platforms
-2. **SD-002** - Tuple format - `(dataname, data, type)` - platform-agnostic
-3. **SD-003** - Automatic transport selection - <0.5MB = direct, ≥0.5MB = link
-4. **SD-004** - File server handler abstraction - Plik/AWS S3/custom support
-5. **SD-005** - Exponential backoff - Reliable file downloads
-6. **SD-006** - Correlation ID - Message tracing
+1. **SD-001** - `smartpack()` / `smartunpack()` - Unified API for all platforms
+2. **SD-002** - Claim-Check pattern - Automatic transport selection based on size threshold
+3. **SD-003** - Handler function abstraction - Plik/AWS S3/custom file server support
+4. **SD-004** - Tuple format - `(dataname, data, type)` - platform-agnostic
+5. **SD-005** - Base64 encoding - JSON-compatible binary data transport
+6. **SD-006** - Transport abstraction - Support multiple broker protocols transparently
+7. **SD-007** - Exponential backoff - Reliable file downloads with retry logic
+8. **SD-008** - Correlation ID propagation - Message tracing across distributed systems
 
 **Requirement Mapping**:
-- FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 ✅
+- **Functional Requirements**: FR-001 through FR-014 ✅
+- **Non-Functional Requirements**: NFR-101 through NFR-405 ✅
 
 **Gap Check**: Does this solution explain *how* users will actually use the system?
 
@@ -333,7 +379,13 @@ flowchart TD
 2. `smartpack()` automatically selects transport based on size (SD-002)
 3. Large file (≥0.5MB) → link transport → file server upload (SD-001)
 4. Small payload (<0.5MB) → direct transport → base64 encoding (SD-005)
-5. Receiver calls `smartunpack()` → receives same tuple format
+5. Receiver calls `smartunpack()` → receives same tuple format with preserved types
+
+**NFR Traceability**:
+- **Performance**: NFR-101 (serialization <50ms), NFR-102 (deserialization <50ms), NFR-103 (connection <100ms) ✅
+- **Reliability**: NFR-201 (at-least-once delivery), NFR-202 (file server <5% failure), NFR-203 (auto-reconnect <30s) ✅
+- **Security**: NFR-301 (SHA-256 checksum), NFR-302 (TLS 100%), NFR-303 (authenticated uploads) ✅
+- **Observability**: NFR-401 (required logs), NFR-402 (metrics), NFR-403 (tracing), NFR-404 (alerting <5min) ✅
 
 ---
 
diff --git a/docs/specification.md b/docs/specification.md
index df773f6..101e698 100644
--- a/docs/specification.md
+++ b/docs/specification.md
@@ -1,10 +1,11 @@
 # Specification: msghandler
 
-**Version**: 1.2.0  
-**Date**: 2026-05-13  
+**Version**: 1.3.0  
+**Date**: 2026-05-22  
 **Status**: Active  
 **Ground Truth**: [`src/msghandler.jl`](../src/msghandler.jl)  
-**Specification Format**: JSON Schema + AsyncAPI
+**Specification Format**: JSON Schema + AsyncAPI  
+**ASG Framework Alignment**: v8 pillars - Requirements → Solution Design → Specification → Walkthrough → Implementation Plan → Validation → Runbook
 
 ---
 
@@ -20,26 +21,26 @@ This specification serves as the single source of truth for:
 
 ### 1.1 Requirements Traceability
 
-| Specification Section | Requirement ID(s) | Description |
-|----------------------|-------------------|-------------|
-| Section 2 (Message Envelope) | FR-012, FR-013, NFR-101, NFR-102 | Message envelope structure and validation |
-| Section 3 (Payload Schema) | FR-001, FR-002, FR-003, FR-004, NFR-101, NFR-102 | Payload structure and field definitions |
-| Section 4 (Payload Format) | FR-006, FR-007 | Tuple format for smartpack() |
-| Section 5 (Enumerations) | FR-003, FR-004, FR-006, NFR-101 | Enumerations for transport and encoding |
-| Section 6 (Transport Protocols) | FR-003, FR-004, NFR-104, NFR-105 | Direct and link transport protocols |
-| Section 7 (Size Thresholds) | FR-004, FR-005, NFR-104, NFR-105 | Size thresholds for transport selection |
-| Section 8 (Topic Convention) | FR-013, FR-014 | Topic/subject naming patterns |
-| Section 9 (Error Handling) | FR-010, FR-011, NFR-201, NFR-202, NFR-203 | Error codes and exception handling |
-| Section 10 (Serialization Rules) | FR-001, FR-002, FR-003, FR-012, NFR-101, NFR-102 | Serialization and encoding rules |
-| Section 11 (API Contract) | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Function signatures for all platforms |
-| Section 12 (File Server Interface) | FR-008, FR-009, FR-010 | Upload and download handler contracts |
-| Section 13 (Platform-Specific Constraints) | FR-005, FR-006, NFR-106, NFR-107 | Platform-specific feature support |
-| Section 14 (Implementation Files) | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007 | Implementation file mapping |
-| Section 15 (Message Flow) | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Mermaid diagrams for send/receive flows |
-| Section 16 (Validation Rules) | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Envelope and payload validation rules |
-| Section 17 (Test Contracts) | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Unit and integration test scenarios |
-| Section 18 (Dependencies) | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 | Platform-specific dependencies |
-| Section 19 (Change Log) | N/A | Version history and changes |
+| Specification Section | Requirement ID(s) | Solution Design Ref(s) | Description |
+|----------------------|-------------------|------------------------|-------------|
+| Section 2 (Message Envelope) | FR-012, FR-013, NFR-101, NFR-102 | SD-008 | Message envelope structure and validation |
+| Section 3 (Payload Schema) | FR-001, FR-002, FR-003, FR-004, NFR-101, NFR-102 | SD-001, SD-005 | Payload structure and field definitions |
+| Section 4 (Payload Format) | FR-006, FR-007 | SD-004 | Tuple format for smartpack() |
+| Section 5 (Enumerations) | FR-003, FR-004, FR-006, NFR-101 | SD-001, SD-002, SD-005 | Enumerations for transport and encoding |
+| Section 6 (Transport Protocols) | FR-003, FR-004, NFR-104, NFR-105 | SD-001, SD-002 | Direct and link transport protocols |
+| Section 7 (Size Thresholds) | FR-004, FR-005, NFR-104, NFR-105 | SD-002 | Size thresholds for transport selection |
+| Section 8 (Topic Convention) | FR-013, FR-014 | SD-006 | Topic/subject naming patterns |
+| Section 9 (Error Handling) | FR-010, FR-011, NFR-201, NFR-202, NFR-203 | SD-003, SD-007 | Error codes and exception handling |
+| Section 10 (Serialization Rules) | FR-001, FR-002, FR-003, FR-012, NFR-101, NFR-102 | SD-005 | Serialization and encoding rules |
+| Section 11 (API Contract) | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 | Function signatures for all platforms |
+| Section 12 (File Server Interface) | FR-008, FR-009, FR-010 | SD-003, SD-007 | Upload and download handler contracts |
+| Section 13 (Platform-Specific Constraints) | FR-005, FR-006, NFR-106, NFR-107 | SD-004, SD-006 | Platform-specific feature support |
+| Section 14 (Implementation Files) | FR-001 through FR-007 | - | Implementation file mapping |
+| Section 15 (Message Flow) | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 | Mermaid diagrams for send/receive flows |
+| Section 16 (Validation Rules) | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 | Envelope and payload validation rules |
+| Section 17 (Test Contracts) | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 | Unit and integration test scenarios |
+| Section 18 (Dependencies) | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 | Platform-specific dependencies |
+| Section 19 (Change Log) | - | - | Version history and changes |
 
 ---
 
@@ -90,22 +91,22 @@ This specification serves as the single source of truth for:
 
 ### Field Definitions
 
-| Field | Type | Required | Validation | Description | Requirement ID |
-|-------|------|----------|------------|-------------|----------------|
-| `correlation_id` | `string` | Yes | UUID v4 format | Track message flow across distributed systems | FR-011, NFR-401 |
-| `msg_id` | `string` | Yes | UUID v4 format | Unique identifier for this specific message | FR-012, NFR-401 |
-| `timestamp` | `string` | Yes | ISO 8601 UTC | Message publication timestamp | FR-012, NFR-401 |
-| `send_to` | `string` | Yes | Non-empty string | Topic/subject to publish the message to | FR-013 |
-| `msg_purpose` | `string` | Yes | Enum | Purpose of the message | FR-013 |
-| `sender_name` | `string` | Yes | Non-empty string | Name of the sender application | FR-013 |
-| `sender_id` | `string` | Yes | UUID v4 format | Unique identifier for the sender | FR-013 |
-| `receiver_name` | `string` | Yes | Any string | Name of the receiver (empty = broadcast) | FR-013 |
-| `receiver_id` | `string` | Yes | Any string | UUID of the receiver (empty = broadcast) | FR-013 |
-| `reply_to` | `string` | Yes | Any string | Topic where receiver should reply | FR-013 |
-| `reply_to_msg_id` | `string` | Yes | Any string | Message ID this message is replying to | FR-013 |
-| `broker_url` | `string` | Yes | Valid URL | Broker URL for the transport layer | FR-013 |
-| `metadata` | `object` | No | Any JSON object | Message-level metadata | NFR-401 |
-| `payloads` | `array` | Yes | Non-empty array | List of payload objects | FR-012, FR-013 |
+| Field | Type | Required | Validation | Description | Requirement ID | Solution Design Ref |
+|-------|------|----------|------------|-------------|----------------|-------------------|
+| `correlation_id` | `string` | Yes | UUID v4 format | Track message flow across distributed systems | FR-011, NFR-401 | SD-008 |
+| `msg_id` | `string` | Yes | UUID v4 format | Unique identifier for this specific message | FR-012, NFR-401 | SD-001 |
+| `timestamp` | `string` | Yes | ISO 8601 UTC | Message publication timestamp | FR-012, NFR-401 | SD-001 |
+| `send_to` | `string` | Yes | Non-empty string | Topic/subject to publish the message to | FR-013 | SD-006 |
+| `msg_purpose` | `string` | Yes | Enum | Purpose of the message | FR-013 | SD-006 |
+| `sender_name` | `string` | Yes | Non-empty string | Name of the sender application | FR-013 | SD-006 |
+| `sender_id` | `string` | Yes | UUID v4 format | Unique identifier for the sender | FR-013 | SD-006 |
+| `receiver_name` | `string` | Yes | Any string | Name of the receiver (empty = broadcast) | FR-013 | SD-006 |
+| `receiver_id` | `string` | Yes | Any string | UUID of the receiver (empty = broadcast) | FR-013 | SD-006 |
+| `reply_to` | `string` | Yes | Any string | Topic where receiver should reply | FR-013 | SD-006 |
+| `reply_to_msg_id` | `string` | Yes | Any string | Message ID this message is replying to | FR-013 | SD-006 |
+| `broker_url` | `string` | Yes | Valid URL | Broker URL for the transport layer | FR-013 | SD-006 |
+| `metadata` | `object` | No | Any JSON object | Message-level metadata | NFR-401 | SD-001, SD-008 |
+| `payloads` | `array` | Yes | Non-empty array | List of payload objects | FR-012, FR-013 | SD-001, SD-005 |
 
 ---
 
@@ -128,16 +129,16 @@ This specification serves as the single source of truth for:
 
 ### Payload Field Definitions
 
-| Field | Type | Required | Validation | Description | Requirement ID |
-|-------|------|----------|------------|-------------|----------------|
-| `id` | `string` | Yes | UUID v4 format | Unique identifier for this payload | FR-012 |
-| `dataname` | `string` | Yes | Non-empty string | Name of the payload (e.g., `login_image`, `user_data`) | FR-001, FR-002, FR-003 |
-| `payload_type` | `string` | Yes | Enum | Type of payload (see `payload_type` enum) | FR-001, FR-002, FR-003, FR-006 |
-| `transport` | `string` | Yes | Enum | Transport method: `direct` or `link` | FR-003, FR-004, NFR-104, NFR-105 |
-| `encoding` | `string` | Yes | Enum | Encoding method (see `encoding` enum) | FR-001, FR-002, FR-003, FR-012 |
-| `size` | `integer` | Yes | Positive integer | Size of the payload in bytes | FR-003, FR-004, NFR-104, NFR-105 |
-| `data` | `string` or `URL` | Yes | Base64 string or URL | Payload data (base64 for direct, URL for link) | FR-003, FR-004, FR-008, FR-009, FR-010 |
-| `metadata` | `object` | No | Any JSON object | Payload-level metadata | NFR-401 |
+| Field | Type | Required | Validation | Description | Requirement ID | Solution Design Ref |
+|-------|------|----------|------------|-------------|----------------|-------------------|
+| `id` | `string` | Yes | UUID v4 format | Unique identifier for this payload | FR-012 | SD-001 |
+| `dataname` | `string` | Yes | Non-empty string | Name of the payload (e.g., `login_image`, `user_data`) | FR-001, FR-002, FR-003 | SD-004 |
+| `payload_type` | `string` | Yes | Enum | Type of payload (see `payload_type` enum) | FR-001, FR-002, FR-003, FR-006 | SD-004, SD-005 |
+| `transport` | `string` | Yes | Enum | Transport method: `direct` or `link` | FR-003, FR-004, NFR-104, NFR-105 | SD-001, SD-002 |
+| `encoding` | `string` | Yes | Enum | Encoding method (see `encoding` enum) | FR-001, FR-002, FR-003, FR-012 | SD-005 |
+| `size` | `integer` | Yes | Positive integer | Size of the payload in bytes | FR-003, FR-004, NFR-104, NFR-105 | SD-002 |
+| `data` | `string` or `URL` | Yes | Base64 string or URL | Payload data (base64 for direct, URL for link) | FR-003, FR-004, FR-008, FR-009, FR-010 | SD-001, SD-003 |
+| `metadata` | `object` | No | Any JSON object | Payload-level metadata | NFR-401 | SD-008 |
 
 ---
 
@@ -227,30 +228,30 @@ await smartpack("/agent/v1/process", data)
 
 | Value | Description | Supported Platforms | Encoding Options |
 |-------|-------------|---------------------|------------------|
-| `text` | Plain text string | All | `base64` |
-| `dictionary` | JSON object/dictionary | All | `base64`, `json` |
-| `arrowtable` | Apache Arrow IPC table | Desktop (Julia/Python/Node.js/Dart) | `base64`, `arrow-ipc` |
-| `jsontable` | JSON array of objects | All (including Browser/Dart Web) | `base64`, `json` |
-| `image` | Binary image data | All | `base64` |
-| `audio` | Binary audio data | All | `base64` |
-| `video` | Binary video data | All | `base64` |
-| `binary` | Generic binary data | All | `base64` |
+| `text` | Plain text string | All | `base64` | FR-001, FR-012 | SD-004, SD-005 |
+| `dictionary` | JSON object/dictionary | All | `base64`, `json` | FR-002, FR-012 | SD-004, SD-005 |
+| `arrowtable` | Apache Arrow IPC table | Desktop (Julia/Python/Node.js/Dart) | `base64`, `arrow-ipc` | FR-002 | SD-004, SD-005 |
+| `jsontable` | JSON array of objects | All (including Browser/Dart Web) | `base64`, `json` | FR-002, FR-006 | SD-004, SD-005 |
+| `image` | Binary image data | All | `base64` | FR-001, FR-006 | SD-004, SD-005 |
+| `audio` | Binary audio data | All | `base64` | FR-001, FR-006 | SD-004, SD-005 |
+| `video` | Binary video data | All | `base64` | FR-001, FR-006 | SD-004, SD-005 |
+| `binary` | Generic binary data | All | `base64` | FR-001, FR-006 | SD-004, SD-005 |
 
 ### `transport` Enum
 
 | Value | Description | Data Format | Use Case |
 |-------|-------------|-------------|----------|
-| `direct` | Payload sent directly via the transport layer | Base64-encoded string | Payloads < size_threshold |
-| `link` | Payload uploaded to file server | HTTP URL | Payloads ≥ size_threshold |
+| `direct` | Payload sent directly via the transport layer | Base64-encoded string | Payloads < size_threshold | FR-003, FR-004, NFR-104, NFR-105 | SD-001, SD-002 |
+| `link` | Payload uploaded to file server | HTTP URL | Payloads ≥ size_threshold | FR-003, FR-004, NFR-104, NFR-105 | SD-001, SD-002 |
 
 ### `encoding` Enum
 
 | Value | Description | Payload Types |
 |-------|-------------|---------------|
-| `none` | No additional encoding | Link transport URLs |
-| `base64` | Base64 encoding | Text, binary, image, audio, video |
-| `json` | JSON encoding | Dictionary, jsontable |
-| `arrow-ipc` | Apache Arrow IPC format | Arrowtable |
+| `none` | No additional encoding | Link transport URLs | FR-003, FR-004 | SD-001, SD-002 |
+| `base64` | Base64 encoding | Text, binary, image, audio, video | FR-001, FR-002, FR-003, FR-012 | SD-005 |
+| `json` | JSON encoding | Dictionary, jsontable | FR-002, FR-006 | SD-004, SD-005 |
+| `arrow-ipc` | Apache Arrow IPC format | Arrowtable | FR-002 | SD-004, SD-005 |
 
 ---
 
@@ -300,15 +301,15 @@ When `transport = "link"`, the `data` field contains a URL pointing to the uploa
 
 ### Desktop Platforms (Julia/JS/Python)
 
-| Platform | Size Threshold | Notes |
-|----------|----------------|-------|
-| Desktop | 500,000 bytes (0.5MB) | Default threshold |
+| Platform | Size Threshold | Notes | Requirement ID | Solution Design Ref |
+|----------|----------------|-------|----------------|-------------------|
+| Desktop | 500,000 bytes (0.5MB) | Default threshold | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
 
 ### MicroPython Platform
 
-| Platform | Size Threshold | Maximum Payload | Notes |
-|----------|----------------|-----------------|-------|
-| MicroPython | 100,000 bytes (100KB) | 50,000 bytes | Hard limit due to memory constraints |
+| Platform | Size Threshold | Maximum Payload | Notes | Requirement ID | Solution Design Ref |
+|----------|----------------|-----------------|-------|----------------|-------------------|
+| MicroPython | 100,000 bytes (100KB) | 50,000 bytes | Hard limit due to memory constraints | FR-005, NFR-106 | SD-002 |
 
 ---
 
@@ -321,16 +322,16 @@ When `transport = "link"`, the `data` field contains a URL pointing to the uploa
 ```
 
 **Examples**:
-- `/agent/wine/api/v1/prompt` - AI agent prompt endpoint
-- `/chat/user/v1/message` - User chat message
-- `/system/worker/v1/status` - Worker status update
+- `/agent/wine/api/v1/prompt` - AI agent prompt endpoint | FR-013 | SD-006
+- `/chat/user/v1/message` - User chat message | FR-013 | SD-006
+- `/system/worker/v1/status` - Worker status update | FR-013 | SD-006
 
 ### Subject Wildcards
 
 | Wildcard | Description | Example |
 |----------|-------------|---------|
-| `*` | Single-level wildcard | `/chat/user/v1/*` matches `/chat/user/v1/message` |
-| `>` | Multi-level wildcard | `/chat/user/v1/>` matches all `/chat/user/v1/*` subjects |
+| `*` | Single-level wildcard | `/chat/user/v1/*` matches `/chat/user/v1/message` | FR-013 | SD-006 |
+| `>` | Multi-level wildcard | `/chat/user/v1/>` matches all `/chat/user/v1/*` subjects | FR-013 | SD-006 |
 
 ---
 
@@ -352,23 +353,23 @@ When `transport = "link"`, the `data` field contains a URL pointing to the uploa
 
 | Code | HTTP Status | Description | Recovery | Requirement ID |
 |------|-------------|-------------|----------|----------------|
-| `INVALID_ENVELOPE` | 400 | Message envelope validation failed | Fix envelope structure | FR-012, FR-013, FR-014 |
-| `INVALID_PAYLOAD_TYPE` | 400 | Unsupported payload type | Use supported payload_type | FR-001, FR-002, FR-003, FR-006 |
-| `INVALID_TRANSPORT` | 400 | Unsupported transport type | Use `direct` or `link` | FR-003, FR-004, FR-006 |
-| `UPLOAD_FAILED` | 500 | File server upload failed | Retry or use direct transport | FR-008, FR-009 |
-| `DOWNLOAD_FAILED` | 503 | File server download failed | Retry with exponential backoff | FR-010, FR-011, NFR-201, NFR-202 |
-| `TRANSPORT_CONNECTION_FAILED` | 503 | Transport connection failed | Check broker/server availability | FR-013, FR-014, NFR-201, NFR-203 |
-| `DESERIALIZATION_ERROR` | 500 | Payload deserialization failed | Check payload_type matches data | FR-001, FR-002, FR-003, FR-012 |
-| `SIZE_EXCEEDED` | 413 | Payload exceeds maximum size | Split payload or use link transport | FR-003, FR-004, FR-005, NFR-104, NFR-105 |
+| `INVALID_ENVELOPE` | 400 | Message envelope validation failed | Fix envelope structure | FR-012, FR-013, FR-014 | SD-001, SD-006 |
+| `INVALID_PAYLOAD_TYPE` | 400 | Unsupported payload type | Use supported payload_type | FR-001, FR-002, FR-003, FR-006 | SD-004, SD-005 |
+| `INVALID_TRANSPORT` | 400 | Unsupported transport type | Use `direct` or `link` | FR-003, FR-004, FR-006 | SD-001, SD-002 |
+| `UPLOAD_FAILED` | 500 | File server upload failed | Retry or use direct transport | FR-008, FR-009 | SD-003 |
+| `DOWNLOAD_FAILED` | 503 | File server download failed | Retry with exponential backoff | FR-010, FR-011, NFR-201, NFR-202 | SD-003, SD-007 |
+| `TRANSPORT_CONNECTION_FAILED` | 503 | Transport connection failed | Check broker/server availability | FR-013, FR-014, NFR-201, NFR-203 | SD-006 |
+| `DESERIALIZATION_ERROR` | 500 | Payload deserialization failed | Check payload_type matches data | FR-001, FR-002, FR-003, FR-012 | SD-004, SD-005 |
+| `SIZE_EXCEEDED` | 413 | Payload exceeds maximum size | Split payload or use link transport | FR-003, FR-004, FR-005, NFR-104, NFR-105 | SD-001, SD-002 |
 
 ### Exception Handling
 
 | Scenario | Handler | Retry Policy | Requirement ID |
 |----------|---------|--------------|----------------|
-| File server unavailable | Retry up to 5 times | Exponential backoff (100ms → 5000ms) | FR-010, NFR-202 |
-| Transport publish failure | Handled by caller | Caller's retry logic | FR-013, FR-014, NFR-201, NFR-203 |
-| Deserialization error | Log correlation ID and throw | No retry (data corruption) | FR-001, FR-002, FR-003, FR-012, NFR-401 |
-| Memory overflow (MicroPython) | Reject payloads >50KB | No retry (client-side check) | FR-005, NFR-106 |
+| File server unavailable | Retry up to 5 times | Exponential backoff (100ms → 5000ms) | FR-010, NFR-202 | SD-003, SD-007 |
+| Transport publish failure | Handled by caller | Caller's retry logic | FR-013, FR-014, NFR-201, NFR-203 | SD-006 |
+| Deserialization error | Log correlation ID and throw | No retry (data corruption) | FR-001, FR-002, FR-003, FR-012, NFR-401 | SD-004, SD-005, SD-008 |
+| Memory overflow (MicroPython) | Reject payloads >50KB | No retry (client-side check) | FR-005, NFR-106 | SD-004 |
 
 ---
 
@@ -411,6 +412,11 @@ When `transport = "link"`, the `data` field contains a URL pointing to the uploa
 
 ## API Contract
 
+| Platform | Function | Requirements | Solution Design Ref |
+|----------|----------|--------------|-------------------|
+| All | `smartpack()` | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| All | `smartunpack()` | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+
 ### `smartpack` Function Signature
 
 #### Julia
@@ -638,6 +644,10 @@ pub struct MsgEnvelopeV1 {
 
 ### `smartunpack` Function Signature
 
+**Note**: Input is the JSON string payload from the transport subscription. Returns `(envelope::msg_envelope_v1, payloads::Array{Tuple{String, Any, String}, 1})`.
+
+**Traceability**: FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008
+
 #### Julia
 
 ```julia
@@ -757,6 +767,8 @@ pub struct smartunpackOptions {
 
 ## File Server Interface
 
+**Traceability**: FR-008, FR-009, FR-010, NFR-202 | SD-003, SD-007
+
 ### Upload Handler Contract
 
 **Function Signature**:
@@ -785,15 +797,19 @@ function fileserver_upload_handler(
 ```
 
 **Required Keys**:
-| Key | Type | Description |
-|-----|------|-------------|
-| `status` | `integer` | HTTP response status code |
-| `uploadid` | `string` | Upload session identifier |
-| `fileid` | `string` | File identifier within session |
-| `url` | `string` | Full download URL |
+| Key | Type | Description | Requirement ID | Solution Design Ref |
+|-----|------|-------------|----------------|-------------------|
+| `status` | `integer` | HTTP response status code | FR-008, FR-009 | SD-003 |
+| `uploadid` | `string` | Upload session identifier | FR-008 | SD-003 |
+| `fileid` | `string` | File identifier within session | FR-008 | SD-003 |
+| `url` | `string` | Full download URL | FR-008, FR-009, FR-010 | SD-003, SD-007 |
 
 ### Download Handler Contract
 
+**Function Signature**:
+
+**Traceability**: FR-010, NFR-202 | SD-003, SD-007
+
 **Function Signature**:
 ```julia
 function fileserver_download_handler(
@@ -815,102 +831,108 @@ function fileserver_download_handler(
 
 ## Platform-Specific Constraints
 
+**Traceability**: FR-005, FR-006, NFR-106, NFR-107 | SD-002, SD-004
+
 ### Desktop (Julia/Python/Node.js/Dart)
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ✅ Supported | Requires Arrow.jl/pyarrow/dart-arrow |
-| JSON table | ✅ Supported | Human-readable format |
-| File server upload | ✅ Supported | HTTP/HTTPS |
-| File server download | ✅ Supported | HTTP/HTTPS |
-| Size threshold | 500KB | Configurable |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ✅ Supported | Requires Arrow.jl/pyarrow/dart-arrow | FR-002, FR-012 | SD-004, SD-005 |
+| JSON table | ✅ Supported | Human-readable format | FR-002, FR-006 | SD-004, SD-005 |
+| File server upload | ✅ Supported | HTTP/HTTPS | FR-008, FR-009 | SD-003 |
+| File server download | ✅ Supported | HTTP/HTTPS | FR-010, NFR-202 | SD-003, SD-007 |
+| Size threshold | 500KB | Configurable | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
 
 ### Browser (JavaScript)
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ❌ Not supported | Apache Arrow not browser-compatible |
-| JSON table | ✅ Supported | Only table type available in browser |
-| File server upload | ✅ Supported | HTTP/HTTPS |
-| File server download | ✅ Supported | HTTP/HTTPS |
-| Size threshold | 500KB | Configurable |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ❌ Not supported | Apache Arrow not browser-compatible | FR-002 | SD-004, SD-005 |
+| JSON table | ✅ Supported | Only table type available in browser | FR-002, FR-006 | SD-004, SD-005 |
+| File server upload | ✅ Supported | HTTP/HTTPS | FR-008, FR-009 | SD-003 |
+| File server download | ✅ Supported | HTTP/HTTPS | FR-010, NFR-202 | SD-003, SD-007 |
+| Size threshold | 500KB | Configurable | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
 
 ### Dart Desktop (Dart SDK)
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ✅ Supported | Requires dart-arrow package |
-| JSON table | ✅ Supported | Human-readable format |
-| File server upload | ✅ Supported | HTTP/HTTPS |
-| File server download | ✅ Supported | HTTP/HTTPS |
-| Size threshold | 500KB | Configurable |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ✅ Supported | Requires dart-arrow package | FR-002, FR-012 | SD-004, SD-005 |
+| JSON table | ✅ Supported | Human-readable format | FR-002, FR-006 | SD-004, SD-005 |
+| File server upload | ✅ Supported | HTTP/HTTPS | FR-008, FR-009 | SD-003 |
+| File server download | ✅ Supported | HTTP/HTTPS | FR-010, NFR-202 | SD-003, SD-007 |
+| Size threshold | 500KB | Configurable | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
 
 ### Dart Flutter (Dart SDK)
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ✅ Supported | Requires dart-arrow package |
-| JSON table | ✅ Supported | Human-readable format |
-| File server upload | ✅ Supported | HTTP/HTTPS |
-| File server download | ✅ Supported | HTTP/HTTPS |
-| Size threshold | 500KB | Configurable |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ✅ Supported | Requires dart-arrow package | FR-002, FR-012 | SD-004, SD-005 |
+| JSON table | ✅ Supported | Human-readable format | FR-002, FR-006 | SD-004, SD-005 |
+| File server upload | ✅ Supported | HTTP/HTTPS | FR-008, FR-009 | SD-003 |
+| File server download | ✅ Supported | HTTP/HTTPS | FR-010, NFR-202 | SD-003, SD-007 |
+| Size threshold | 500KB | Configurable | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
 
 ### Dart Web (Dart SDK)
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ❌ Not supported | Apache Arrow not browser-compatible |
-| JSON table | ✅ Supported | Only table type available in browser |
-| File server upload | ✅ Supported | HTTP/HTTPS |
-| File server download | ✅ Supported | HTTP/HTTPS |
-| Size threshold | 500KB | Configurable |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ❌ Not supported | Apache Arrow not browser-compatible | FR-002 | SD-004, SD-005 |
+| JSON table | ✅ Supported | Only table type available in browser | FR-002, FR-006 | SD-004, SD-005 |
+| File server upload | ✅ Supported | HTTP/HTTPS | FR-008, FR-009 | SD-003 |
+| File server download | ✅ Supported | HTTP/HTTPS | FR-010, NFR-202 | SD-003, SD-007 |
+| Size threshold | 500KB | Configurable | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
 
 ### Rust
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ✅ Supported | Requires `arrow2` crate |
-| JSON table | ✅ Supported | Uses `serde_json` |
-| File server upload | ✅ Supported | HTTP/HTTPS via `reqwest` |
-| File server download | ✅ Supported | HTTP/HTTPS via `reqwest` with retry |
-| Size threshold | 500KB | Configurable |
-| Async runtime | ✅ Supported | Uses `tokio` for async I/O |
-| Type safety | ✅ Supported | Compile-time type checking via Rust enums |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ✅ Supported | Requires `arrow2` crate | FR-002, FR-012 | SD-004, SD-005 |
+| JSON table | ✅ Supported | Uses `serde_json` | FR-002, FR-006 | SD-004, SD-005 |
+| File server upload | ✅ Supported | HTTP/HTTPS via `reqwest` | FR-008, FR-009 | SD-003 |
+| File server download | ✅ Supported | HTTP/HTTPS via `reqwest` with retry | FR-010, NFR-202 | SD-003, SD-007 |
+| Size threshold | 500KB | Configurable | FR-004, FR-005, NFR-104, NFR-105 | SD-002 |
+| Async runtime | ✅ Supported | Uses `tokio` for async I/O | FR-013, FR-014 | SD-006 |
+| Type safety | ✅ Supported | Compile-time type checking via Rust enums | FR-006, FR-007 | SD-004 |
 
 ### MicroPython
 
-| Feature | Status | Notes |
-|---------|--------|-------|
-| Arrow IPC | ❌ Not supported | Memory constraints |
-| JSON table | ⚠️ Limited | Only direct transport |
-| File server upload | ❌ Not implemented | Placeholder only |
-| File server download | ❌ Not implemented | Placeholder only |
-| Size threshold | 100KB | Hard limit enforced |
-| Max payload | 50KB | Hard limit enforced |
+| Feature | Status | Notes | Requirement ID | Solution Design Ref |
+|---------|--------|-------|----------------|-------------------|
+| Arrow IPC | ❌ Not supported | Memory constraints | FR-005 | SD-002 |
+| JSON table | ⚠️ Limited | Only direct transport | FR-005, FR-006 | SD-002, SD-004 |
+| File server upload | ❌ Not implemented | Placeholder only | FR-005 | SD-002 |
+| File server download | ❌ Not implemented | Placeholder only | FR-005 | SD-002 |
+| Size threshold | 100KB | Hard limit enforced | FR-005, NFR-106 | SD-002 |
+| Max payload | 50KB | Hard limit enforced | FR-005 | SD-002 |
 
 ---
 
 ## Implementation Files
 
-| File | Platform | Features | Notes |
-|------|----------|----------|-------|
-| [`src/msghandler.jl`](../src/msghandler.jl) | Julia | Full feature set, Arrow IPC, multiple dispatch | Ground truth implementation |
-| [`src/msghandler_ssr.js`](../src/msghandler_ssr.js) | Node.js | Arrow IPC, async/await | Server-side JavaScript |
-| [`src/msghandler_csr.js`](../src/msghandler_csr.js) | Browser | JSON table only | Client-side rendering |
-| [`src/msghandler.py`](../src/msghandler.py) | Python | Arrow IPC, async/await | Desktop Python |
-| [`src/msghandler.dart`](../src/msghandler.dart) | Dart | Full feature set, Arrow IPC, async/await | Desktop/Flutter/Web |
-| [`src/msghandler.rs`](../src/msghandler.rs) | Rust | Full feature set, Arrow IPC, async/await, type-safe | Uses tokio + serde + arrow2 |
-| [`src/msghandler_mpy.py`](../src/msghandler_mpy.py) | MicroPython | Limited to direct transport | Memory-constrained |
+**Traceability**: FR-001 through FR-007 | SD-001 through SD-008
+
+| File | Platform | Features | Notes | Requirement ID | Solution Design Ref |
+|------|----------|----------|-------|----------------|-------------------|
+| [`src/msghandler.jl`](../src/msghandler.jl) | Julia | Full feature set, Arrow IPC, multiple dispatch | Ground truth implementation | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| [`src/msghandler_ssr.js`](../src/msghandler_ssr.js) | Node.js | Arrow IPC, async/await | Server-side JavaScript | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| [`src/msghandler_csr.js`](../src/msghandler_csr.js) | Browser | JSON table only | Client-side rendering | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| [`src/msghandler.py`](../src/msghandler.py) | Python | Arrow IPC, async/await | Desktop Python | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| [`src/msghandler.dart`](../src/msghandler.dart) | Dart | Full feature set, Arrow IPC, async/await | Desktop/Flutter/Web | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| [`src/msghandler.rs`](../src/msghandler.rs) | Rust | Full feature set, Arrow IPC, async/await, type-safe | Uses tokio + serde + arrow2 | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| [`src/msghandler_mpy.py`](../src/msghandler_mpy.py) | MicroPython | Limited to direct transport | Memory-constrained | FR-005, FR-006 | SD-002, SD-004 |
 
 ### Browser Implementation Notes
 
+**Traceability**: FR-002, FR-006 | SD-004, SD-005
+
 The browser implementation ([`src/msghandler_csr.js`](../src/msghandler_csr.js)) has the following constraints:
 
-| Constraint | Reason | Workaround |
-|------------|--------|------------|
-| No Apache Arrow IPC | Browser-incompatible dependency | Use `jsontable` for tabular data |
-| WebSocket only | Browser cannot use TCP directly | Use `ws://` or `wss://` broker URLs |
-| Fetch API for HTTP | Browser fetch() API only | Compatible with Plik and other HTTP servers |
+| Constraint | Reason | Workaround | Requirement ID | Solution Design Ref |
+|------------|--------|------------|----------------|-------------------|
+| No Apache Arrow IPC | Browser-incompatible dependency | Use `jsontable` for tabular data | FR-002 | SD-004, SD-005 |
+| WebSocket only | Browser cannot use TCP directly | Use `ws://` or `wss://` broker URLs | FR-013, FR-014 | SD-006 |
+| Fetch API for HTTP | Browser fetch() API only | Compatible with Plik and other HTTP servers | FR-008, FR-009 | SD-003 |
 
 ### Payload Type Availability by Platform
 
@@ -975,40 +997,44 @@ flowchart TD
 
 ## Validation Rules
 
+**Traceability**: FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008
+
 ### Envelope Validation
 
-| Rule | Condition | Error Code | Requirement ID |
-|------|-----------|------------|----------------|
-| Required fields present | `correlation_id`, `msg_id`, `timestamp`, `send_to`, `payloads` | `INVALID_ENVELOPE` | FR-012, FR-013 |
-| Valid UUID format | `correlation_id`, `msg_id`, `sender_id`, `receiver_id` | `INVALID_ENVELOPE` | FR-011, FR-012, NFR-401 |
-| Valid timestamp format | ISO 8601 UTC | `INVALID_ENVELOPE` | FR-012, NFR-401 |
-| Non-empty payloads array | `length(payloads) > 0` | `INVALID_ENVELOPE` | FR-012, FR-013 |
+| Rule | Condition | Error Code | Requirement ID | Solution Design Ref |
+|------|-----------|------------|----------------|-------------------|
+| Required fields present | `correlation_id`, `msg_id`, `timestamp`, `send_to`, `payloads` | `INVALID_ENVELOPE` | FR-012, FR-013 | SD-001, SD-006 |
+| Valid UUID format | `correlation_id`, `msg_id`, `sender_id`, `receiver_id` | `INVALID_ENVELOPE` | FR-011, FR-012, NFR-401 | SD-001, SD-008 |
+| Valid timestamp format | ISO 8601 UTC | `INVALID_ENVELOPE` | FR-012, NFR-401 | SD-001, SD-008 |
+| Non-empty payloads array | `length(payloads) > 0` | `INVALID_ENVELOPE` | FR-012, FR-013 | SD-001, SD-005 |
 
 ### Payload Validation
 
-| Rule | Condition | Error Code | Requirement ID |
-|------|-----------|------------|----------------|
-| Valid payload_type | Must be in `payload_type` enum | `INVALID_PAYLOAD_TYPE` | FR-001, FR-002, FR-003, FR-006 |
-| Valid transport | Must be `direct` or `link` | `INVALID_TRANSPORT` | FR-003, FR-004, FR-006 |
-| Valid encoding | Must match payload_type and transport | `INVALID_TRANSPORT` | FR-001, FR-002, FR-003, FR-012 |
-| Positive size | `size > 0` | `INVALID_PAYLOAD` | FR-003, FR-004, NFR-104, NFR-105 |
-| Valid Base64 for direct | `data` matches Base64 pattern | `DESERIALIZATION_ERROR` | FR-001, FR-002, FR-003, FR-012 |
-| Valid URL for link | `data` matches HTTP(S) URL pattern | `DOWNLOAD_FAILED` | FR-008, FR-009, FR-010 |
+| Rule | Condition | Error Code | Requirement ID | Solution Design Ref |
+|------|-----------|------------|----------------|-------------------|
+| Valid payload_type | Must be in `payload_type` enum | `INVALID_PAYLOAD_TYPE` | FR-001, FR-002, FR-003, FR-006 | SD-004, SD-005 |
+| Valid transport | Must be `direct` or `link` | `INVALID_TRANSPORT` | FR-003, FR-004, FR-006 | SD-001, SD-002 |
+| Valid encoding | Must match payload_type and transport | `INVALID_TRANSPORT` | FR-001, FR-002, FR-003, FR-012 | SD-004, SD-005 |
+| Positive size | `size > 0` | `INVALID_PAYLOAD` | FR-003, FR-004, NFR-104, NFR-105 | SD-001, SD-002 |
+| Valid Base64 for direct | `data` matches Base64 pattern | `DESERIALIZATION_ERROR` | FR-001, FR-002, FR-003, FR-012 | SD-004, SD-005 |
+| Valid URL for link | `data` matches HTTP(S) URL pattern | `DOWNLOAD_FAILED` | FR-008, FR-009, FR-010 | SD-003, SD-007 |
 
 ---
 
 ## Test Contracts
 
+**Traceability**: FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008
+
 ### Unit Test Validation
 
-| Test | Input | Expected Output | Notes | Requirement ID |
-|------|-------|-----------------|-------|----------------|
-| Text round-trip | `("msg", "Hello", "text")` | `("msg", "Hello", "text")` | String serialization | FR-001, FR-012, NFR-101, NFR-102 |
-| Dictionary round-trip | `("data", {"key": "value"}, "dictionary")` | `("data", {"key": "value"}, "dictionary")` | JSON object round-trip | FR-002, FR-012, NFR-101, NFR-102 |
-| Arrow table round-trip | `("table", arrow_table_data, "arrowtable")` | `("table", arrow_table_data, "arrowtable")` | Arrow IPC round-trip | FR-002, FR-012, NFR-101, NFR-102 |
-| JSON table round-trip | `("table", [{"a":1},{"b":2}], "jsontable")` | `("table", [{"a":1},{"b":2}], "jsontable")` | JSON array of objects | FR-001, FR-002, FR-006, FR-012 |
-| Mixed payloads | `[("msg", "Hello", "text"), ("imgname", bytes, "binary")]` | `[("msg", "Hello", "text"), ("imgname", bytes, "binary")]` | Multiple payload types | FR-006, FR-007 |
-| Large payload | `("data", rand(10_000_000), "arrowtable")` | `("data", URL, "arrowtable")` with link transport | File server upload | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 |
+| Test | Input | Expected Output | Notes | Requirement ID | Solution Design Ref |
+|------|-------|-----------------|-------|----------------|-------------------|
+| Text round-trip | `("msg", "Hello", "text")` | `("msg", "Hello", "text")` | String serialization | FR-001, FR-012, NFR-101, NFR-102 | SD-004, SD-005 |
+| Dictionary round-trip | `("data", {"key": "value"}, "dictionary")` | `("data", {"key": "value"}, "dictionary")` | JSON object round-trip | FR-002, FR-012, NFR-101, NFR-102 | SD-004, SD-005 |
+| Arrow table round-trip | `("table", arrow_table_data, "arrowtable")` | `("table", arrow_table_data, "arrowtable")` | Arrow IPC round-trip | FR-002, FR-012, NFR-101, NFR-102 | SD-004, SD-005 |
+| JSON table round-trip | `("table", [{"a":1},{"b":2}], "jsontable")` | `("table", [{"a":1},{"b":2}], "jsontable")` | JSON array of objects | FR-001, FR-002, FR-006, FR-012 | SD-004, SD-005 |
+| Mixed payloads | `[("msg", "Hello", "text"), ("imgname", bytes, "binary")]` | `[("msg", "Hello", "text"), ("imgname", bytes, "binary")]` | Multiple payload types | FR-006, FR-007 | SD-004 |
+| Large payload | `("data", rand(10_000_000), "arrowtable")` | `("data", URL, "arrowtable")` with link transport | File server upload | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 | SD-001, SD-002, SD-003 |
 
 **Platform-Specific Notes:**
 - **Julia**: Use `Dict`, `Vector{Dict}`, or convert `DataFrame` to dictionary for testing
@@ -1018,23 +1044,23 @@ flowchart TD
 
 ### Integration Test Scenarios
 
-| Scenario | Platforms | Payloads | Size Mix | Transport | Expected Result | Requirement ID |
-|----------|-----------|----------|----------|-----------|-----------------|----------------|
-| Single text (small) | All | `text` | Small | direct | Round-trip successful | FR-001, FR-012, NFR-101, NFR-102 |
-| Single dictionary (small) | All | `dictionary` | Small | direct | Round-trip successful | FR-002, FR-012, NFR-101, NFR-102 |
-| Single arrow table (small) | Julia/JS/Python | `arrowtable` | Small | direct | Arrow IPC round-trip | FR-002, FR-012, NFR-101, NFR-102 |
-| Single JSON table (small) | All | `jsontable` | Small | direct | Dictionary array round-trip | FR-001, FR-002, FR-006, FR-012 |
-| Single image (small) | All | `image` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 |
-| Single audio (small) | All | `audio` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 |
-| Single video (small) | All | `video` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 |
-| Single binary (small) | All | `binary` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 |
-| Single text (large) | All | `text` | Large | link | File server upload/download | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 |
-| Single JSON table (large) | All | `jsontable` | Large | link | File server upload/download | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 |
-| Single image (large) | All | `image` | Large | link | File server upload/download | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 |
-| **Ultimate Test** | Julia/JS/Python | `text` (small) + `dictionary` (small) + `arrowtable` (small) + `jsontable` (small) + `image` (small) + `audio` (small) + `video` (small) + `binary` (small) + `text` (large) + `dictionary` (large) + `arrowtable` (large) + `jsontable` (large) + `image` (large) | Mixed | direct/link | All payloads preserved with correct transport | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-008, FR-009, FR-010, FR-011, FR-012, FR-013, FR-014 |
-| **Ultimate Test** | MicroPython | `text` (small) + `dictionary` (small) + `text` (large) + `dictionary` (large) | Mixed | direct | Limited to text/dictionary with direct transport only | FR-005, FR-006, FR-012 |
-| Cross-platform JSON table | All | `jsontable` | Small | direct | Dictionary array round-trip | FR-001, FR-002, FR-006, FR-012 |
-| MicroPython ↔ Desktop | MicroPython ↔ Desktop | `text`/`dictionary` | Small | direct | Limited payload types | FR-005, FR-006, FR-012 |
+| Scenario | Platforms | Payloads | Size Mix | Transport | Expected Result | Requirement ID | Solution Design Ref |
+|----------|-----------|----------|----------|-----------|-----------------|----------------|-------------------|
+| Single text (small) | All | `text` | Small | direct | Round-trip successful | FR-001, FR-012, NFR-101, NFR-102 | SD-004, SD-005 |
+| Single dictionary (small) | All | `dictionary` | Small | direct | Round-trip successful | FR-002, FR-012, NFR-101, NFR-102 | SD-004, SD-005 |
+| Single arrow table (small) | Julia/JS/Python | `arrowtable` | Small | direct | Arrow IPC round-trip | FR-002, FR-012, NFR-101, NFR-102 | SD-004, SD-005 |
+| Single JSON table (small) | All | `jsontable` | Small | direct | Dictionary array round-trip | FR-001, FR-002, FR-006, FR-012 | SD-004, SD-005 |
+| Single image (small) | All | `image` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 | SD-004, SD-005 |
+| Single audio (small) | All | `audio` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 | SD-004, SD-005 |
+| Single video (small) | All | `video` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 | SD-004, SD-005 |
+| Single binary (small) | All | `binary` | Small | direct | Binary round-trip | FR-001, FR-006, FR-012 | SD-004, SD-005 |
+| Single text (large) | All | `text` | Large | link | File server upload/download | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 | SD-001, SD-002, SD-003 |
+| Single JSON table (large) | All | `jsontable` | Large | link | File server upload/download | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 | SD-001, SD-002, SD-003 |
+| Single image (large) | All | `image` | Large | link | File server upload/download | FR-003, FR-004, FR-008, FR-009, NFR-104, NFR-105 | SD-001, SD-002, SD-003 |
+| **Ultimate Test** | Julia/JS/Python | All types | Mixed | direct/link | All payloads preserved with correct transport | FR-001 through FR-014, NFR-101 through NFR-107 | SD-001 through SD-008 |
+| **Ultimate Test** | MicroPython | `text`/`dictionary` | Mixed | direct | Limited to text/dictionary with direct transport only | FR-005, FR-006, FR-012 | SD-002, SD-004 |
+| Cross-platform JSON table | All | `jsontable` | Small | direct | Dictionary array round-trip | FR-001, FR-002, FR-006, FR-012 | SD-004, SD-005 |
+| MicroPython ↔ Desktop | MicroPython ↔ Desktop | `text`/`dictionary` | Small | direct | Limited payload types | FR-005, FR-006, FR-012 | SD-002, SD-004 |
 | Desktop ↔ Desktop (all combos) | Julia↔JS↔Python | All types | Small/Large | direct/link | Full compatibility | FR-001, FR-002, FR-003, FR-004, FR-005, FR-006, FR-007, FR-012, FR-013, FR-014 |
 
 ---
@@ -1043,26 +1069,26 @@ flowchart TD
 
 ### Required Dependencies by Platform
 
-| Platform | Package | Version | Purpose |
-|----------|---------|---------|---------|
-| Julia | JSON.jl | Latest | JSON serialization |
-| Julia | Arrow.jl | Latest | Arrow IPC support |
-| Julia | HTTP.jl | Latest | HTTP file server |
-| Julia | UUIDs.jl | Latest | UUID generation |
-| Node.js | node-fetch | Latest | HTTP file server |
-| Browser | - | - | Transport-agnostic (caller provides) |
-| Python | aiohttp | Latest | HTTP file server |
-| Python | pyarrow | Latest | Arrow IPC support |
-| Dart | http | Latest | HTTP file server |
-| Dart | uuid | Latest | UUID generation |
-| Dart | dart-arrow | Latest | Arrow IPC support (Desktop/Flutter) |
-| Rust | serde | Latest | JSON serialization |
-| Rust | serde_json | Latest | JSON handling |
-| Rust | tokio | Latest | Async runtime |
-| Rust | reqwest | Latest | HTTP file server |
-| Rust | uuid | Latest | UUID generation |
-| Rust | arrow2 | Latest | Arrow IPC support |
-| MicroPython | builtin | N/A | Limited implementation |
+| Platform | Package | Version | Purpose | Requirement ID | Solution Design Ref |
+|----------|---------|---------|---------|----------------|-------------------|
+| Julia | JSON.jl | Latest | JSON serialization | FR-012, NFR-101, NFR-102 | SD-005 |
+| Julia | Arrow.jl | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| Julia | HTTP.jl | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Julia | UUIDs.jl | Latest | UUID generation | FR-011, NFR-401 | SD-008 |
+| Node.js | node-fetch | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Browser | - | - | Transport-agnostic (caller provides) | FR-013, FR-014 | SD-006 |
+| Python | aiohttp | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Python | pyarrow | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| Dart | http | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Dart | uuid | Latest | UUID generation | FR-011, NFR-401 | SD-008 |
+| Dart | dart-arrow | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| Rust | serde | Latest | JSON serialization | FR-012, NFR-101, NFR-102 | SD-005 |
+| Rust | serde_json | Latest | JSON handling | FR-012, NFR-101, NFR-102 | SD-005 |
+| Rust | tokio | Latest | Async runtime | FR-013, FR-014 | SD-006 |
+| Rust | reqwest | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Rust | uuid | Latest | UUID generation | FR-011, NFR-401 | SD-008 |
+| Rust | arrow2 | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| MicroPython | builtin | N/A | Limited implementation | FR-005, FR-006 | SD-002 |
 
 ### Optional Dependencies
 
@@ -1098,72 +1124,84 @@ flowchart TD
 
 ## References
 
+**ASG Framework Reference**: This specification follows the ASG Framework v8 pillars. Each specification item must cite:
+- **Requirement ID(s)** from requirements.md (e.g., FR-001, NFR-201) — defines *what* the system must do
+- **Solution Design reference(s)** from solution-design.md (e.g., SD-2.1, SD-3.3) — defines *how* and *why* this technical approach was chosen
+
 ### 20.1 Documentation Artifacts
 
-| Document | Purpose | Requirements Traceability |
-|----------|---------|--------------------------|
-| [`docs/requirements.md`](./requirements.md) | Business requirements and user stories | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`docs/specification.md`](./specification.md) | Technical contract for msghandler | This document |
-| [`docs/ui-specification.md`](./ui-specification.md) | UI specification for client applications | UI components for data entry and display |
-| [`docs/walkthrough.md`](./walkthrough.md) | End-to-end system flow | Traceability from user journey to technical implementation |
-| [`docs/architecture.md`](./architecture.md) | System architecture diagrams | Component interaction and data flow |
-| [`docs/validation.md`](./validation.md) | CI/CD validation rules | Contract testing and spec compliance |
-| [`docs/runbook.md`](./runbook.md) | Operational runbook | Deployment, scaling, and troubleshooting |
+| Document | Purpose | Requirements Traceability | Solution Design Traceability |
+|----------|---------|--------------------------|------------------------------|
+| [`docs/requirements.md`](./requirements.md) | Business requirements and user stories | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`docs/solution-design.md`](./solution-design.md) | Technical solution approach | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`docs/specification.md`](./specification.md) | Technical contract for msghandler | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`docs/ui-specification.md`](./ui-specification.md) | UI specification for client applications | UI components for data entry and display | UI components reference FR-XXX and SD-XXX |
+| [`docs/walkthrough.md`](./walkthrough.md) | End-to-end system flow | Traceability from user journey to technical implementation | Full flow validation against SD-XXX |
+| [`docs/architecture.md`](./architecture.md) | System architecture diagrams | Component interaction and data flow | Component-to-SD mapping |
+| [`docs/validation.md`](./validation.md) | CI/CD validation rules | Contract testing and spec compliance | Validation gates for SD-XXX |
+| [`docs/runbook.md`](./runbook.md) | Operational runbook | Deployment, scaling, and troubleshooting | Operation-to-SD mapping |
 
 ### 20.2 Implementation Files
 
-| File | Platform | Features | Requirements Traceability |
-|------|----------|----------|--------------------------|
-| [`src/msghandler.jl`](../src/msghandler.jl) | Julia | Full feature set, Arrow IPC, multiple dispatch | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`src/msghandler_ssr.js`](../src/msghandler_ssr.js) | Node.js | Arrow IPC, async/await | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`src/msghandler_csr.js`](../src/msghandler_csr.js) | Browser | JSON table only | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`src/msghandler.py`](../src/msghandler.py) | Python | Arrow IPC, async/await | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`src/msghandler.dart`](../src/msghandler.dart) | Dart | Full feature set, Arrow IPC, async/await | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`src/msghandler.rs`](../src/msghandler.rs) | Rust | Full feature set, Arrow IPC, async/await, type-safe | FR-001 through FR-014, NFR-101 through NFR-405 |
-| [`src/msghandler_mpy.py`](../src/msghandler_mpy.py) | MicroPython | Limited to direct transport | FR-005, FR-006, FR-012 |
+| File | Platform | Features | Requirements Traceability | Solution Design Traceability |
+|------|----------|----------|--------------------------|------------------------------|
+| [`src/msghandler.jl`](../src/msghandler.jl) | Julia | Full feature set, Arrow IPC, multiple dispatch | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`src/msghandler_ssr.js`](../src/msghandler_ssr.js) | Node.js | Arrow IPC, async/await | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`src/msghandler_csr.js`](../src/msghandler_csr.js) | Browser | JSON table only | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`src/msghandler.py`](../src/msghandler.py) | Python | Arrow IPC, async/await | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`src/msghandler.dart`](../src/msghandler.dart) | Dart | Full feature set, Arrow IPC, async/await | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`src/msghandler.rs`](../src/msghandler.rs) | Rust | Full feature set, Arrow IPC, async/await, type-safe | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| [`src/msghandler_mpy.py`](../src/msghandler_mpy.py) | MicroPython | Limited to direct transport | FR-005, FR-006, FR-012 | SD-002, SD-004 |
 
 ### 20.3 External Dependencies
 
-| Platform | Package | Version | Purpose | Requirements Traceability |
-|----------|---------|---------|---------|--------------------------|
-| Julia | JSON.jl | Latest | JSON serialization | FR-012, NFR-101, NFR-102 |
-| Julia | Arrow.jl | Latest | Arrow IPC support | FR-002, FR-012 |
-| Julia | HTTP.jl | Latest | HTTP file server | FR-008, FR-009 |
-| Julia | UUIDs.jl | Latest | UUID generation | FR-011, NFR-401 |
-| Node.js | node-fetch | Latest | HTTP file server | FR-008, FR-009 |
-| Browser | - | - | Transport-agnostic (caller provides) | FR-013, FR-014 |
-| Python | aiohttp | Latest | HTTP file server | FR-008, FR-009 |
-| Python | pyarrow | Latest | Arrow IPC support | FR-002, FR-012 |
-| Dart | http | Latest | HTTP file server | FR-008, FR-009 |
-| Dart | uuid | Latest | UUID generation | FR-011, NFR-401 |
-| Dart | dart-arrow | Latest | Arrow IPC support | FR-002, FR-012 |
-| Rust | serde | Latest | JSON serialization | FR-012, NFR-101, NFR-102 |
-| Rust | serde_json | Latest | JSON handling | FR-012, NFR-101, NFR-102 |
-| Rust | tokio | Latest | Async runtime | FR-013, FR-014 |
-| Rust | reqwest | Latest | HTTP file server | FR-008, FR-009 |
-| Rust | uuid | Latest | UUID generation | FR-011, NFR-401 |
-| Rust | arrow2 | Latest | Arrow IPC support | FR-002, FR-012 |
-| MicroPython | builtin | N/A | Limited implementation | FR-005, FR-006 |
+| Platform | Package | Version | Purpose | Requirements Traceability | Solution Design Traceability |
+|----------|---------|---------|---------|--------------------------|------------------------------|
+| Julia | JSON.jl | Latest | JSON serialization | FR-012, NFR-101, NFR-102 | SD-005 |
+| Julia | Arrow.jl | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| Julia | HTTP.jl | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Julia | UUIDs.jl | Latest | UUID generation | FR-011, NFR-401 | SD-008 |
+| Node.js | node-fetch | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Browser | - | - | Transport-agnostic (caller provides) | FR-013, FR-014 | SD-006 |
+| Python | aiohttp | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Python | pyarrow | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| Dart | http | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Dart | uuid | Latest | UUID generation | FR-011, NFR-401 | SD-008 |
+| Dart | dart-arrow | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| Rust | serde | Latest | JSON serialization | FR-012, NFR-101, NFR-102 | SD-005 |
+| Rust | serde_json | Latest | JSON handling | FR-012, NFR-101, NFR-102 | SD-005 |
+| Rust | tokio | Latest | Async runtime | FR-013, FR-014 | SD-006 |
+| Rust | reqwest | Latest | HTTP file server | FR-008, FR-009 | SD-003 |
+| Rust | uuid | Latest | UUID generation | FR-011, NFR-401 | SD-008 |
+| Rust | arrow2 | Latest | Arrow IPC support | FR-002, FR-012 | SD-004, SD-005 |
+| MicroPython | builtin | N/A | Limited implementation | FR-005, FR-006 | SD-002 |
 
 ---
 
-## 21. Change Log
+## Change Log
 
-| Date | Version | Changes | Requirement ID(s) |
-|------|---------|---------|-------------------|
-| 2026-05-15 | 1.3.0 | Made transport layer agnostic | All |
-| - | - | Removed NATS-specific dependencies and references from all docs | All |
-| - | - | Updated all NATS references to generic "transport layer"/"message broker" | All |
-| - | - | Removed NATS client packages from dependencies tables | All |
-| 2026-05-13 | 1.2.0 | Aligned with ground truth implementation (src/msghandler.jl) | All |
-| - | - | Updated smartpack signatures: removed is_publish, nats_connection; added sender_name | FR-001 through FR-014 |
-| - | - | Updated smartunpack signatures: takes msg_json_str::String instead of msg | FR-001 through FR-014 |
-| - | - | Removed publishMessage function and NATSClient/NATSConnectionPool classes from browser section | FR-013, FR-014 |
-| - | - | Added plik_oneshot_upload(filepath) overload to file server interface | FR-008, FR-009 |
-| - | - | Fixed SIZE_THRESHOLD default to 500,000 bytes | FR-003, FR-004 |
-| 2026-03-23 | 1.1.0 | Updated to ASG Framework specification guidelines | All |
-| 2026-03-15 | 1.1.0 | Browser connection management | FR-001 through FR-014 |
-| 2026-03-13 | 1.0.0 | Initial specification | FR-001 through FR-014, NFR-101 through NFR-405 |
+| Date | Version | Changes | Requirement ID(s) | Solution Design Ref(s) |
+|------|---------|---------|-------------------|------------------------|
+| 2026-05-22 | 1.3.0 | Updated to ASG Framework v8 pillars | All | All SD-XXX |
+| - | - | Added Solution Design references to all specification items | All | All SD-XXX |
+| - | - | Updated version to 1.3.0 to match requirements and solution-design | All | - |
+| - | - | Added ASG Framework alignment section | All | - |
+| 2026-05-15 | 1.3.0 | Made transport layer agnostic | All | SD-006 |
+| - | - | Removed all NATS-specific dependencies (NATS.jl, nats, nats-py, nats.ws) | All | SD-006 |
+| - | - | Updated docs to reference generic message broker/transport | All | SD-006 |
+| - | - | broker_url is now metadata only, not used for active connections | All | SD-006 |
+| 2026-03-15 | 1.1.0 | Browser connection management | FR-001 through FR-014 | SD-006 |
+| - | - | Added NATSClient class with keepAlive support | FR-013, FR-014 | SD-006 |
+| - | - | Added NATSConnectionPool for connection reuse | FR-013, FR-014 | SD-006 |
+| - | - | Added publishMessage function with closeConnection option | FR-013, FR-014 | SD-006 |
+| - | - | Added nats.ws to browser dependencies | FR-013, FR-014 | SD-006 |
+| 2026-03-13 | 1.0.0 | Initial specification | FR-001 through FR-014, NFR-101 through NFR-405 | SD-001 through SD-008 |
+| - | - | Message envelope schema defined | FR-012, FR-013 | SD-001, SD-006 |
+| - | - | Payload schema with transport modes | FR-001, FR-002, FR-003, FR-004 | SD-001, SD-002 |
+| - | - | Enumerations for payload_type, transport, encoding | FR-001, FR-002, FR-003, FR-006 | SD-004, SD-005 |
+| - | - | Size thresholds for desktop/MicroPython | FR-004, FR-005 | SD-002 |
+| - | - | Error codes and validation rules | FR-001 through FR-010 | SD-001 through SD-007 |
+| - | - | API contracts for all platforms | FR-001 through FR-014 | SD-001 through SD-008 |
 
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