Kafka Transactional IdDistributed Systems & Databases
All trialsGPT-5.4codexTrial 01
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GPT-5.4Fail
Trial 01 — 1st of 8 by reward score. This model averages 0% across 8 trials on this task.
- 24Turns
- $0.11Cost
- 0.7mTime
- 4kOutput tokens
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User prompt → 24 turns → final responsecodex
1systempermissions instructions · Filesystem sandboxing defines which files can be read or written. sandbox_mode is danger-full…
permissions instructions
Filesystem sandboxing defines which files can be read or written.
sandbox_modeisdanger-full-access: No filesystem sandboxing - all commands are permitted. Network access is enabled.
Approval policy is currently never. Do not provide thesandbox_permissionsfor any reason, commands will be rejected.skills instructions
Skills
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SKILL.mdsource. Below is the list of skills that can be used. Each entry includes a name, description, and source locator.filelocators are on the host filesystem,environment resourcelocators are owned by an execution environment,orchestrator resourcelocators are opaque non-filesystem resources, andcustom resourcelocators use their provider's access mechanism.Available skills
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… 1,000 more characters in the raw trajectory.
2userenvironment context · /app bash 2026-07-17 Etc/UTC /app
environment context
- cwd
- /app
- shell
- bash
- current date
- 2026-07-17
- timezone
- Etc/UTC
- root
- /app
3userKafka Exactly-Once Payment Duplication A Kafka-based payment processing pipeline, deployed as a replicated Kubernetes wo…
Kafka Exactly-Once Payment Duplication
A Kafka-based payment processing pipeline, deployed as a replicated Kubernetes workload, has started producing duplicate records in the downstream accounting database after a Kubernetes migration.
- Duplication rate: ~0.02% (about 200 duplicates per million payments)
- Started three weeks ago, coinciding with a Kubernetes migration
- Pipeline ran correctly for six months before the migration
- Kafka broker logs are clean
- Producer EOS configuration appears correct
Fix the pipeline so that a 1-hour production run at 10,000 messages/second with pod restarts every 60 seconds produces zero duplicate payment records in the accounting database while maintaining throughput >= 9,500 msg/sec. Do not change the following exactly-once semantics configuration:
- Producer:
enable.idempotence=true,acks=all - Consumer:
isolation.level=read_committed
Do not mask the problem with additional deduplication or duplicate suppression layers. The duplicates must be prevented at the source.
Your
fixed_producer.pyartifact will be evaluated as a standalone Python file; it must not depend on other files under/app.Write the following artifacts to
/logs/artifacts/:fixed_producer.py— the corrected, self-contained producerconsumer.py— a copy of the unchanged consumersimulation_result.json— result of running/app/simulation.pyagainstfixed_producer.pyroot_cause.txt— a brief explanation of the root cause and the fix
4I’m inspecting the pipeline code and simulation harness first so I can identify where the migration introduced duplicate…
I’m inspecting the pipeline code and simulation harness first so I can identify where the migration introduced duplicate production behavior and fix it at the source.
5Executed exec_command call_Nti5nI79nUr4sIgIfR4RBnCI
Executed exec_command call_Nti5nI79nUr4sIgIfR4RBnCI
6Executed exec_command call_aFlHjLIiQJFOX9ALdXZItNtu
Executed exec_command call_aFlHjLIiQJFOX9ALdXZItNtu
7I have the relevant files. Next I’m reading the producer, consumer, identity code, deployment config, and the simulation…
I have the relevant files. Next I’m reading the producer, consumer, identity code, deployment config, and the simulation harness to map the failure mode to the Kubernetes migration.
8Executed exec_command call_bJSuIz20SEirh5KNCxVIomBy
Executed exec_command call_bJSuIz20SEirh5KNCxVIomBy
9Executed exec_command call_JzipxFHg9cebkr99iySRKOyW
Executed exec_command call_JzipxFHg9cebkr99iySRKOyW
10Executed exec_command call_tbnBkqgUd7JNVpvjB6cm5u3c
Executed exec_command call_tbnBkqgUd7JNVpvjB6cm5u3c
11Executed exec_command call_TcpHS8ZreQiSRZsWkn2vfGIq
Executed exec_command call_TcpHS8ZreQiSRZsWkn2vfGIq
12Executed exec_command call_9Yfz2rYKWTyJkr1ZUyulc5Ou
Executed exec_command call_9Yfz2rYKWTyJkr1ZUyulc5Ou
13The failure condition is in the producer identity path, not Kafka EOS settings. I’m checking the runbook for any platfor…
The failure condition is in the producer identity path, not Kafka EOS settings. I’m checking the runbook for any platform assumptions, then I’ll patch a self-contained producer that derives a stable per-replica transactional ID across pod restarts.
14Executed exec_command call_mQ5GqfCzWHzAe7tnGrEHUPex
Executed exec_command call_mQ5GqfCzWHzAe7tnGrEHUPex
15Executed exec_command call_fJiRiVg8YRzLEIkGChDMmGU3
Executed exec_command call_fJiRiVg8YRzLEIkGChDMmGU3
16Executed update_plan call_O8ctgjPNzOnItrhcIr1K0ksv
Executed update_plan call_O8ctgjPNzOnItrhcIr1K0ksv
17I have the fix shape now: keep the Kafka EOS settings as-is, replace the unstable pod-name/hostname-based transactional…
I have the fix shape now: keep the Kafka EOS settings as-is, replace the unstable pod-name/hostname-based transactional identity with a stable replica identity, and fail closed if the platform doesn’t provide one. I’m writing the standalone producer and the artifact notes next.
18Executed exec_command call_ERcgqkrUbDWcDzv8cyIB0umA
Executed exec_command call_ERcgqkrUbDWcDzv8cyIB0umA
19Executed apply_patch call_3elNViH3ngVrvTQajb4xW1sF
Executed apply_patch call_3elNViH3ngVrvTQajb4xW1sF
20The producer artifact is in place. I’m copying the consumer verbatim and then running the simulator against the fixed pr…
The producer artifact is in place. I’m copying the consumer verbatim and then running the simulator against the fixed producer to confirm zero duplicates at the required rate.
21Executed exec_command call_n3k8Y4Hy6ePWvXYZlChAMhBt
Executed exec_command call_n3k8Y4Hy6ePWvXYZlChAMhBt
22Executed exec_command call_6UhVyCT8W2azLsFhJNjp4J9M
Executed exec_command call_6UhVyCT8W2azLsFhJNjp4J9M
23Executed update_plan call_zQJAhgHK3ufBVwXSqb44IJYG
Executed update_plan call_zQJAhgHK3ufBVwXSqb44IJYG
24Artifacts are in /logs/artifacts: - [fixed_producer.py](/logs/artifacts/fixed_producer.py) - [consumer.py](/logs/artifac…
Artifacts are in
/logs/artifacts:- fixed_producer.py
- consumer.py
- simulation_result.json
- root_cause.txt
The fix is in the producer identity path:
transactional_idnow comes from a restart-stable replica ordinal instead ofPOD_NAME/HOSTNAME, which were changing after the Kubernetes migration and breaking Kafka producer epoch fencing. The corrected producer is self-contained, keepsenable.idempotence=true,acks=all, and the consumer remains unchanged.Verification: running
/app/simulation.pyagainst the fixed producer producedduplicates: 0,throughput: 10000, anddynamic_transactional_id: false, which satisfies the zero-duplicate and>= 9500 msg/secrequirements.