feat: refine Produce stage descriptions to clarify handling of multiple topics and partitions, including validation, response structure, and offset management

Author: ryan-gang

stage_descriptions/produce-06_mf2.md

@@ -4,8 +4,6 @@ In this stage, you'll add support for producing to multiple partitions of the sa
 
 When a Kafka broker receives a Produce request targeting multiple partitions of the same topic, it needs to validate that the topic and all partitions exist, write records to each partition's log file independently, and return a response containing results for all partitions. Each partition maintains its own offset sequence independently, so partition 0 and partition 1 can both have records starting at offset 0.
 
-The request will contain multiple RecordBatches, one for each partition. Each RecordBatch will contain a single record. 
-
 We've created an interactive protocol inspector for the request & response structures for `Produce`:
 
 - 🔎 [Produce Request (v11)](https://binspec.org/kafka-produce-request-v11)
@@ -20,6 +18,7 @@ The tester will execute your program like this:
 ```
 
 It'll then connect to your server on port 9092 and send a `Produce` (v11) request targeting multiple partitions of the same topic.
+The request will contain multiple RecordBatches, one for each partition. Each RecordBatch will contain a single record. 
 
 The tester will validate that:
 

stage_descriptions/produce-07_ar4.md

@@ -2,7 +2,12 @@ In this stage, you'll add support for producing to multiple topics in a single r
 
 ## Cross-Topic Production
 
-Your Kafka implementation should handle complex requests with multiple topics, manage independent offset tracking per topic and partition, and handle complex response structures. Each topic maintains completely independent offset sequences.
+When a Kafka broker receives a Produce request targeting multiple topics with their respective partitions, it needs to validate that all topics and partitions exist, write records to each topic-partition's log file independently, and return a nested response structure containing results for all topics and their partitions. Each topic-partition combination maintains its own independent offset sequence, so topic "foo" partition 0 and topic "bar" partition 0 can both have records starting at offset 0.
+
+We've created an interactive protocol inspector for the request & response structures for `Produce`:
+
+- 🔎 [Produce Request (v11)](https://binspec.org/kafka-produce-request-v11)
+- 🔎 [Produce Response (v11)](https://binspec.org/kafka-produce-response-v11)
 
 ## Tests
 
@@ -13,6 +18,7 @@ The tester will execute your program like this:
 ```
 
 It'll then connect to your server on port 9092 and send a `Produce` (v11) request targeting multiple topics with their respective partitions.
+The request will contain data for multiple topics, and a single partition for each topic. 
 
 The tester will validate that:
 
@@ -25,19 +31,14 @@ The tester will validate that:
   - The correct `name` field matching the topic name in the request.
   - Each partition in the request has a corresponding partition response.
   - Each partition response contains:
-    - The correct `partition` field matching the request.
+    - The correct `index` field matching the partition in the request.
     - An error code of `0` (NO_ERROR).
-    - A valid `offset` field with the assigned offset for that topic-partition.
-    - A valid `timestamp` field.
-    - A correct `log_start_offset` field.
+    - A valid `base_offset` field with the assigned offset for that topic-partition.
+    - The `log_append_time_ms` field contains `-1` (signifying that the timestamp is latest).
+    - The `log_start_offset` field is `0`.
 - Records are persisted to the correct topic-partition log files.
 - Offset assignment is independent per topic-partition combination.
 
 ## Notes
 
-- Each topic-partition combination maintains its own independent offset sequence.
-- Multiple topics can be written to simultaneously in a single request.
-- The response structure is nested: topics contain partition responses.
-- Topic-level and partition-level errors should be handled independently.
-- This is the most complex produce scenario, combining multi-topic and multi-partition handling.
-- The official docs for the `Produce` request can be found [here](https://kafka.apache.org/protocol.html#The_Messages_Produce).
+- The official docs for the `Produce` request can be found [here](https://kafka.apache.org/protocol.html#The_Messages_Produce). Make sure to scroll down to the "Produce Response (Version: 11)" section.