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-communicationgit 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-communication)<a href="https://agentmods.dev/skills/hoangnguyen0403/agent-skills-standard/system-design-communication"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/system-design-communication/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-communication"><img src="https://agentmods.dev/badge/skills/hoangnguyen0403/agent-skills-standard/system-design-communication.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 | $0.00071 | $0.00828 |
| Opus 5.5 | $0.00028 | $0.00331 |
| Sonnet 5.5 | $0.00014 | $0.00166 |
| Haiku 4.5 | $0.00007 | $0.00083 |
Grade A, and why
system-design-communication 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 — 70 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Communication Selection
Priority: P1 (HIGH)
Choose the paradigm per hop from the constraint, not from familiarity. One flow may legitimately use three.
Paradigm Table
| Constraint observed | Paradigm | Cost accepted |
|---|---|---|
| Resource CRUD for broad, unknown clients; HTTP caching wanted | REST | Over/under-fetching; N round trips for aggregates |
| Internal service-to-service, low latency, streaming, schema-first | gRPC | Browser needs a proxy; L7 balancers need HTTP/2 awareness |
| One client aggregates many sources with client-shaped responses | GraphQL | Query-cost limits and N+1 resolvers become your problem |
| Bidirectional real-time (chat, collaboration, gaming) | WebSocket | Stateful connections; LB affinity; reconnect protocol |
| Server push only (feeds, progress, notifications) | SSE | One direction; plain HTTP, auto-reconnect built in |
| Cross-organization async callback | Webhook | Receiver retries, signature verification, idempotency required |
Sync vs Async per Flow
- Choose synchronous work when the caller needs its result to continue and the invariant requires it; bound it by the end-to-end deadline and define timeout, failure, and fallback behavior.
- Choose asynchronous work when the caller needs eventual completion rather than the result now; return a trackable operation ID or use a defined push contract.
- Set the number of synchronous dependencies from the invariant, dependency budgets, deadline, operational coupling, and failure semantics. A bounded chain of more than two hops can be valid; even one hop can be unacceptable if it breaks those constraints.
Service Discovery
- Start with DNS-based discovery of a load balancer; it is discovery enough for most systems.
- Move to a health-checked registry (server-side discovery) when instances churn faster than DNS TTLs propagate.
- Client-side discovery only when the client must pick the instance (cache affinity, zone-local routing); it couples every client to the registry.
What ships with it
2 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.
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 Changed 032fb36ac807
- 1mo ago First seen · 70 lines · 71 tokens per session scan A 3d035b641496
system-design-communication is a skill published in the GitHub repository HoangNguyen0403/agent-skills-standard (583 stars, last pushed today), licensed MIT. It adds 71 tokens to every session and 828 once invoked, about $0.0003 per session on Opus 5.5. 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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