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 skills add nWave-ai/nWave --skill nw-sd-case-studiesgit clone --depth 1 https://github.com/nWave-ai/nWaveWrote 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/nwave-ai/nwave/nw-sd-case-studies)<a href="https://agentmods.dev/skills/nwave-ai/nwave/nw-sd-case-studies"><img src="https://agentmods.dev/badge/skills/nwave-ai/nwave/nw-sd-case-studies.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector pass
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 5.1 | $0.00040 | $0.02865 |
| Opus 5 | $0.00020 | $0.01432 |
| Sonnet 5 | $0.00008 | $0.00573 |
| Haiku 4.5 | $0.00004 | $0.00286 |
Grade A, and why
nw-sd-case-studies 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 yesterday.
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 — 110 lines — stays where its author put it; the contents beside it link to each section on GitHub.
System Design Case Studies
Reference catalog of 25 real-world designs. Use when designing a similar system or needing precedent for architectural decisions.
Volume 1 Case Studies
Rate Limiter
Scale: API gateway middleware | Core: Token Bucket (industry standard) or Sliding Window Counter | Storage: Redis counters with TTL | Distributed: Lua scripts for atomic increment | Key insight: cross-cutting concern, belongs in middleware/gateway | Headers: 429 + Retry-After + X-RateLimit-Remaining
Consistent Hashing
Core: hash ring 0 to 2^32-1, servers at positions, keys walk clockwise | Virtual nodes: 100-200 per server, reduces load deviation from ~40% to ~5% | Used in: DynamoDB, Cassandra, Akamai, Discord | Key insight: never deploy without virtual nodes
Key-Value Store (Dynamo-style)
Core: consistent hashing for partitioning, N replicas on clockwise nodes, quorum W+R>N | Conflict: vector clocks, LWW, app-level merge | Failures: sloppy quorum + hinted handoff (temp), Merkle trees + anti-entropy (permanent), gossip for detection | Write path: WAL -> memtable -> SSTable (LSM-tree) | Read path: memtable -> Bloom filter -> SSTable(s)
Unique ID Generator
Winner: Snowflake -- 64-bit, sortable, minimal coordination | [1 unused | 41 timestamp | 5 DC | 5 machine | 12 sequence] ~4M IDs/sec/DC | Weakness: clock sync (NTP) | Alt: UUID (128-bit, not sortable), ticket server (SPOF)
URL Shortener
Scale: 100M/day ~ 1,160 QPS write, 11,600 read | Short URL: base62 with 7 chars = 3.5T combinations | Approaches: hash + collision resolution | base62 from auto-increment ID | pre-generated key service | Redirect: 301 (cached, no analytics) vs 302 (every click tracked) -- most use 302 | Key: caching critical (heavy-tailed distribution)
Web Crawler
Scale: 1B pages/month ~ 400 pages/sec, 500TB storage/month | Core: URL Frontier with priority queues (importance) + politeness queues (per-domain rate limit) | Dedup: SHA-256 exact, simhash/MinHash near-duplicate | Traps: URL length limit, max depth, blacklist | Key insight: URL frontier is the most important component
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.
- yesterday First seen · 110 lines · 40 tokens per session scan A fe998efd26c5
nw-sd-case-studies is a skill published in the GitHub repository nWave-ai/nWave (608 stars, last pushed 2d ago), licensed MIT. It adds 40 tokens to every session and 2,865 once invoked, about $0.0002 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 2026-09-06.
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