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 d-padmanabhan/agent-engineering-handbook --skill networking-transportgit clone --depth 1 https://github.com/d-padmanabhan/agent-engineering-handbookWrote 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/d-padmanabhan/agent-engineering-handbook/networking-transport)<a href="https://agentmods.dev/skills/d-padmanabhan/agent-engineering-handbook/networking-transport"><img src="https://agentmods.dev/badge/skills/d-padmanabhan/agent-engineering-handbook/networking-transport/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/d-padmanabhan/agent-engineering-handbook/networking-transport"><img src="https://agentmods.dev/badge/skills/d-padmanabhan/agent-engineering-handbook/networking-transport.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 | $0.00118 | $0.06106 |
| Opus 5 | $0.00059 | $0.03053 |
| Sonnet 5 | $0.00024 | $0.01221 |
| Haiku 4.5 | $0.00012 | $0.00611 |
Grade A, and why
networking-transport scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Makes network callslowCapability
Not a fault in itself. Listed so you know the mod talks to something, and to what.
- **Client must support and choose to attempt H3.** Browsers do this transparently; SDKs / curl need explicit flags. How it starts
The opening of the file, as written. The whole thing — 483 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Networking & Transport - Architecture Patterns
The transport-and-wire-format layer underneath API design. The API design skill (${HANDBOOK_ROOT}/skills/api-design/SKILL.md) and rule (${HANDBOOK_ROOT}/rules/320-api-design.mdc) cover the API surface. This skill covers TCP, HTTP/n, QUIC, serialization, connection lifecycle, head-of-line blocking, and TTFB budgets.
Get this layer wrong and your P99 latency, mobile UX, edge cold-start cost, and east-west microservice throughput all suffer in ways that profiling your application code can't fix.
When to invoke
- Designing or reviewing a service-to-service API (REST vs gRPC choice)
- Debugging tail latency / TTFB spikes / "fast in isolation, slow in production"
- Configuring load balancer idle timeouts (NLB, ALB, API Gateway, Cloudflare)
- Designing long-lived connections (websockets, SSE, gRPC streaming)
- Evaluating HTTP/3 / QUIC for mobile / cross-region / lossy-network workloads
- Choosing a wire format (JSON vs Protobuf vs MessagePack vs Avro)
- Reviewing a
.protofile or a protobuf schema change
Five golden rules
- TCP keepalive is mandatory on long-lived clients. Linux defaults (
tcp_keepalive_time = 7200s= 2 hours) are wrong for cloud. Set explicit per-language values. - Reuse HTTP clients. A fresh client per request defeats keepalive and burns ~50-150ms on TCP+TLS handshake. The single most common production performance bug.
- Choose the wire by callers, not by hype. External / browser / human-debugged -> REST/JSON. Internal east-west / polyglot / streaming -> gRPC/Protobuf. Don't gRPC your public API just because it's faster.
- HTTP/2 multiplexes streams; HTTP/3 multiplexes connections. HTTP/2 still has TCP-level head-of-line. HTTP/3 fixes it. Matters when packet loss is non-zero (mobile, satellite, cross-region).
- Idle timeouts kill connections silently. AWS NLB drops at 350s, ALB at 60s, API Gateway REST at 29s. Set keepalive < min(idle timeout) or watch your "random" disconnects.
What ships with it
4 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.
- 4d ago Changed a846ffe9ecdb
- 9d ago First seen · 483 lines · 118 tokens per session scan A b457e92f0070
networking-transport is a skill published in the GitHub repository d-padmanabhan/agent-engineering-handbook (17 stars, last pushed today), licensed MIT. It adds 118 tokens to every session and 6,106 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.
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