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 HoangNguyen0403/agent-skills-standard --skill system-design-estimationgit clone --depth 1 https://github.com/HoangNguyen0403/agent-skills-standardWrote 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/hoangnguyen0403/agent-skills-standard/system-design-estimation)<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/system-design-estimation"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/system-design-estimation/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/system-design-estimation"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/system-design-estimation.svg" alt="Reviewed on agentmods" width="80" 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 | $0.00051 | $0.00851 |
| Opus 5 | $0.00026 | $0.00426 |
| Sonnet 5 | $0.00010 | $0.00170 |
| Haiku 4.5 | $0.00005 | $0.00085 |
Grade A, and why
system-design-estimation 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 13d 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 — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Capacity Estimation
Priority: P1 (HIGH)
Estimate before you architect. One order of magnitude decides cache, shard, and queue choices.
Core Formulas
average QPS = DAU x actions per user per day / 86,400peak QPS = average QPS x peak factor(default 5x; 20-100x for flash sale, ticket drop, or scheduled push)storage per year = writes per day x record size x 365 x replication factorbandwidth = QPS x payload size(compute ingress and egress separately)working set = hot records x record size, where hot is typically 20% of data serving 80% of readsconnections = concurrent users x connections per user; compare against pool and file-descriptor limits
Method
- Round every input to one significant figure. Precision here is false precision.
- Compute average, then peak, then storage, then bandwidth, then memory.
- Compare each result to a known ceiling from estimation numbers: single-node QPS, disk IOPS, NIC throughput, RAM per instance.
- Name the shaping quantity - the first number that breaks a single-node ceiling. It dictates the first component added in high-level design.
- Restate every assumed input beside the result so a wrong assumption is visible, not buried.
Cost
- Convert the sized capacity into monthly spend before recommending it: compute, storage plus egress, managed-service premiums, and the multiplier any redundancy applies.
- Cost is a design constraint, not an afterthought. A topology the budget cannot hold is not a design, it is a proposal to be rejected later.
- State cost per unit of value where it clarifies: cost per 1k requests, per GB retained, per nine of availability added.
Latency Budget
- Build the p95 budget as a sum of hops; every remote call spends from one fixed budget.
- Use order-of-magnitude anchors: memory 100ns, SSD read 100us, same-DC round trip 500us, cross-region round trip 100ms+.
- A synchronous fan-out of N calls costs the slowest call, not the average. Budget with p99, not the mean.
What ships with it
1 file 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.
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.
- 13d ago First seen · 75 lines · 51 tokens per session scan A 9fccdf2f4400
system-design-estimation is a skill published in the GitHub repository HoangNguyen0403/agent-skills-standard (565 stars, last pushed 3d ago), licensed MIT. It adds 51 tokens to every session and 851 once invoked, about $0.0003 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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server-setup
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