Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add skills/shenli/distributed-system-testing/designing-distributed-system-testsnpx skills add shenli/distributed-system-testing --skill designing-distributed-system-testsgit clone --depth 1 https://github.com/shenli/distributed-system-testingWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/shenli/distributed-system-testing/designing-distributed-system-tests)<a href="https://agentmods.dev/skills/shenli/distributed-system-testing/designing-distributed-system-tests"><img src="https://agentmods.dev/badge/skills/shenli/distributed-system-testing/designing-distributed-system-tests.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00211 | $0.06466 |
| Opus 5 | $0.00105 | $0.03233 |
| Sonnet 5 | $0.00042 | $0.01293 |
| Haiku 4.5 | $0.00021 | $0.00647 |
Grade A, and why
designing-distributed-system-tests scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 560 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Designing Distributed-System Tests
The default for testing distributed and stateful systems — write a few integration tests and call it done — finds a small fraction of the bugs that actually break these systems in production. This skill enforces an opinionated workflow: scope the change, generate failure-mode hypotheses that cover the categories the literature says matter most, pick techniques from a curated catalog, and emit a structured plan file that the executing-distributed-system-tests skill (or a human) can run.
Plan modes
This skill produces two shapes of plan. Decide which one applies before you start; the steps below branch on it.
- Change-scoped — the default. Use when the caller names a commit, PR, branch-diff, or feature. The plan covers what this change could regress, scoped by its blast radius.
- Project-wide — use when the caller asks for a "release-validation plan", "stability plan for the whole system", "test plan to enough coverage", "what should we be testing", or otherwise frames the request without a specific change. The plan covers what the system should be tested for, with an explicit inventory of existing tests and a gap analysis driving the new-scenario list.
If the framing is ambiguous, ask once before starting — the modes diverge enough that retrofitting one into the other wastes work.
Process
Follow these steps in order. Do not skip; the order matters because later steps depend on artifacts the earlier steps produce.
1. Scope the system
Read the project's entry points: README, AGENTS.md or CLAUDE.md,
top-level docs/, any existing test-plan or runbook files. Note:
- Tenancy / isolation model
- Persistence model (what is durable, fsync contract)
- Replication / consensus protocol, quorum, leadership
- Ordering guarantee exposed to clients
- Network boundaries (which RPCs / streams)
- Retry / idempotency contract
- Observability (logs, metrics, traces) available to an oracle
Write this as a one-paragraph SUT model. If anything is ambiguous from the repo, ask the user before proceeding — do not invent guarantees.
What ships with it
13 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- assets/plan-template.md 21 KB
- references/boundary-and-isolation-testing.md 8.2 KB
- references/catalog-index.md 3.6 KB
- references/chaos-and-fault-injection.md 2.8 KB
- references/common-distributed-systems-pitfalls.md 20 KB
- references/crash-recovery-and-upgrade.md 2.8 KB
- references/deterministic-simulation.md 2.5 KB
- references/formal-methods-tla.md 2.7 KB
- references/fuzzing.md 2.7 KB
- references/history-discipline.md 7.7 KB
- references/jepsen-and-elle.md 2.4 KB
- references/performance-and-benchmarking.md 2.7 KB
- references/property-and-metamorphic.md 2.6 KB
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 560 lines · 0 tokens per session scan A 739f8930711d
designing-distributed-system-tests is a skill published in the GitHub repository shenli/distributed-system-testing (229 stars, last pushed 1mo ago), licensed MIT. It adds 211 tokens to every session and 6,466 once invoked, about $0.0011 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
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cli-local-build
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