update

docs/implementation.md

@@ -146,7 +146,22 @@ All three implementations (Julia, JavaScript, Python/Micropython) follow the sam
       └─────────────────┘                 └─────────────────┘
 ```
 
-## Files
+## smartsend Return Value
+
+The `smartsend` function now returns a tuple containing both the envelope object and the JSON string representation:
+
+```julia
+env, msg_json_str = smartsend(...)
+# env::msgEnvelope_v1    - The envelope object with all metadata and payloads
+# msg_json_str::String   - JSON string for publishing to NATS
+```
+
+**Options:**
+- `is_publish::Bool = true` - When `true` (default), the message is automatically published to NATS. When `false`, the function returns the envelope and JSON string without publishing, allowing manual publishing via NATS request-reply pattern.
+
+This enables two use cases:
+1. **Programmatic envelope access**: Access envelope fields directly via the `env` object
+2. **Direct JSON publishing**: Publish the JSON string directly using NATS request-reply pattern
 
 ### Julia Module: [`src/NATSBridge.jl`](../src/NATSBridge.jl)
 
@@ -345,7 +360,9 @@ df = DataFrame(
 )
 
 # Send via SmartSend - wrapped in a list (type is part of each tuple)
-await SmartSend("analysis_results", [("table_data", df, "table")]);
+env, msg_json_str = SmartSend("analysis_results", [("table_data", df, "table")])
+# env: msgEnvelope_v1 object with all metadata and payloads
+# msg_json_str: JSON string representation of the envelope for publishing
 ```
 
 #### JavaScript (Receiver)