system-design-case-catalog SKILL.md skillA
This file is byte-identical to the first copy the registry indexed. Same content hash, so the same checks give both the same grade.
system-design-case-catalog from hoangnguyen0403/agent-skills-standard is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add hoangnguyen0403/agent-skills-standard/system-design-case-catalog@git:20261021.8da3953Pins git:20261021.8da3953 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- hoangnguyen0403/agent-skills-standard
- Path
.claude/skills/system-design/system-design-case-catalog/SKILL.md- Versions recorded
- 4
- Latest version
- git:20261021.8da3953, committed Oct 21, 2026
- First version recorded
- Aug 30, 2026
- Size
- 4,496 bytes
- Repository stars
- 583
- License
- MIT
Answer classic system design problems as constraint-to-solution sketches and coach interview practice: URL shortener, rate limiter, news feed, chat, notification, autocomplete, crawler, unique id. Use for interview practice or naming the closest known shape for a new problem.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Case Catalog ## **Priority: P2 (MEDIUM)** Each classic problem has one defining constraint. Name it first; the rest of the design follows. ## Defining Constraints | Problem | Defining constraint | Decisions that follow | | --- | --- | --- | | URL shortener | Read-heavy by ~100:1, key must be short and unique | Base62 of a distributed counter, cache-first read path, 301 vs 302 choice | | Rate limiter | Decision must be cheap, shared, and correct under concurrency | Token bucket in a shared counter, fail-open or fail-closed rule, `429` plus `Retry-After` | | News feed | Fan-out cost versus read latency, with celebrity skew | Push for normal accounts, pull for celebrities, hybrid merge at read | | Chat | Delivery guarantees and presence at persistent-connection scale | WebSocket gateways, per-conversation ordering, offline queue, read receipts | | Notification | Multi-channel delivery with retries and dedupe | Queue per channel, idempotency key, user preference and quiet hours | | Autocomplete | Sub-100ms prefix lookup over a huge term space | Trie or prefix index in memory, precomputed top-k per prefix, async rebuild | …
Read the whole file at its exact version.
How to install
mdr add hoangnguyen0403/agent-skills-standard/system-design-case-catalog@sha256:ac58772c156cc4dbThe line at the top of this page pins the label git:20261021.8da3953, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_i4wuljtvhxgajapd)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 4 versions of this file, between Aug 30, 2026 and Oct 21, 2026, about one every 17 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261021.8da3953 latest | 2026-10-21 | 8da3953 | 4,496 B | A | view · diff |
| git:20260923.330e3b8 | 2026-09-23 | 330e3b8 | 4,392 B | A | view · diff |
| git:20260913.a7ccfad | 2026-09-13 | a7ccfad | 3,610 B | A | view · diff |
| git:20260830.00e03f4 | 2026-08-30 | 00e03f4 | 3,289 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (4496 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
hoangnguyen0403/agent-skills-standard · 583 stars · license MIT · pushed 2026-11-07 · branch develop
API
GET https://markdownregistry.com/api/v1/artifacts/art_i4wuljtvhxgajapd GET https://markdownregistry.com/api/v1/resolve?ref=hoangnguyen0403/agent-skills-standard/system-design-case-catalog GET https://markdownregistry.com/api/v1/blob/ac58772c156cc4db0c9ddb9f07c369267007819db5eb2c39fe380cfdc5ce50e1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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