jepsen-testing
Jepsen-style correctness testing for distributed systems under faults (partitions, crashes, clock skew) using concurrent operation histories and formal checkers (linearizability/serializability and Elle-style anomalies). Use when designing, implementing, or running Jepsen tests, or interpreting histories/violations.
Best use case
jepsen-testing is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
Jepsen-style correctness testing for distributed systems under faults (partitions, crashes, clock skew) using concurrent operation histories and formal checkers (linearizability/serializability and Elle-style anomalies). Use when designing, implementing, or running Jepsen tests, or interpreting histories/violations.
Teams using jepsen-testing should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/jepsen-testing/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How jepsen-testing Compares
| Feature / Agent | jepsen-testing | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
Jepsen-style correctness testing for distributed systems under faults (partitions, crashes, clock skew) using concurrent operation histories and formal checkers (linearizability/serializability and Elle-style anomalies). Use when designing, implementing, or running Jepsen tests, or interpreting histories/violations.
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
# Jepsen Testing ## Intake - Identify the system under test and the exact client surface (Redis, S3, Kafka, HTTP, gRPC). - Define what "acknowledged" means for each operation (what does the client treat as committed). - Write the claimed consistency guarantees as a checkable property (linearizable register, RYW, monotonic reads, serializable txns). - Specify the failure model to test (crash-stop, partitions, clock skew, disk stalls, restarts). - Decide whether the test must be multi-surface (write via Redis, read via S3) to validate cross-frontend coherence. ## Workload Design - Prefer the smallest workload that can falsify the claim. - Use a mix of reads and writes that creates ambiguous interleavings. - Add a "witness" invariant that is easy to explain: - Lost acknowledged write. - Read sees a value that cannot be explained by any sequential execution respecting real-time order. - List-append: element lost/duplicated or observed order implies a cycle. ## Checker Selection - Register or map semantics: use a linearizability checker. - Transactional / multi-object semantics: use Elle-style anomaly detection (write cycles, dirty reads, lost updates). - If linearizability is too strong for the product, explicitly select a weaker model and encode it (do not silently downgrade). ## Fault (Nemesis) Selection - Partitions: majority/minority splits, bridge partitions, flapping partitions. - Process faults: kill and restart, node reboot, rolling restarts. - Time faults: clock offsets and jumps if the system relies on time. - Storage faults: fsync latency, I/O stalls, disk-full behavior (only if safe and reversible). ## Run and Minimize - Start with a short, low-concurrency run until the harness is stable. - When a failure appears, minimize by reducing: - Keys, operation count, and concurrency. - Fault intensity and schedule complexity. - Preserve determinism (fixed seeds, fixed partition schedule) so a failing history can be reproduced. ## Reporting - State the exact claim under test and the precise pass/fail property. - Include the workload, nemesis schedule, and a minimal failing history excerpt. - Distinguish availability failures (timeouts) from safety failures (incorrect ok results).
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