network-defense

network-defense is a skill for Claude Code, Codex from Miosa-osa/OSA. It costs 44 tokens per session (429 once invoked), scanned A, original, Apache-2.0.

A guide for reviewing network exposure, firewall rules, and intrusion-detection evidence. It checks defensive changes with traffic that should be allowed and traffic that should be blocked.

In plain words
What is it for?
It helps review segmentation, Suricata rules, firewall policies, and packet captures, then validate the results.
Why use it?
It helps find unwanted network access and verify that policy changes work as intended. It keeps firewall and intrusion-detection decisions tied to observable traffic.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps review segmentation, Suricata rules, firewall policies, and packet captures, then validate the results.

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Install with agentmods
npx agentmods add skills/miosa-osa/osa/network-defense
Install

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.

Any agent
npx skills add Miosa-osa/OSA --skill network-defense
Clone the repo
git clone --depth 1 https://github.com/Miosa-osa/OSA

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for network-defense

README.md
[![agentmods](https://agentmods.dev/badge/skills/miosa-osa/osa/network-defense/github.svg)](https://agentmods.dev/skills/miosa-osa/osa/network-defense)
Your own site
<a href="https://agentmods.dev/skills/miosa-osa/osa/network-defense"><img src="https://agentmods.dev/badge/skills/miosa-osa/osa/network-defense/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.

agentmods 80×15 button for network-defense

Your own site · 80×15
<a href="https://agentmods.dev/skills/miosa-osa/osa/network-defense"><img src="https://agentmods.dev/badge/skills/miosa-osa/osa/network-defense.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 44 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 429 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00044 $0.00429
Opus 5.5 $0.00018 $0.00172
Sonnet 5.5 $0.00009 $0.00086
Haiku 4.5 $0.00004 $0.00043

Measured 1mo ago against content hash b84a18a6c28c, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

network-defense 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 1mo 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.

priv/skills/network-defense/SKILL.md · 40 lines

What it actually says

Network Defense

Workflow

  1. Map required flows: source, destination, protocol, port and owner. Inventory listeners and actual firewall policy without changing it.
  2. Compare exposure against the map; distinguish listening interfaces from remotely reachable services.
  3. For offline IDS analysis, read the Suricata workflow and verify the binary, config and packet fixture exist.
  4. Validate both suspicious and allowed traffic; record capture visibility, rule versions and loss counters.
  5. Prepare minimal policy changes with an out-of-band recovery path and exact rollback. Retest the denied path and permitted health checks after changes.
  6. Do not claim offline detection proves inline blocking or complete network visibility.

Worked example and prerequisites

Read references/workflow.md before execution. Use only registered OSA tools named in the frontmatter; command examples run through shell_execute. Check command -v for each external executable on the actual target. Optional packages, external collectors and vendor accounts are not bundled or presumed installed.

Evidence and completion

Return scope, prerequisites, exact checks, observed results, evidence paths, limitations, remediation, rollback and retest status. Mark unavailable checks as blocked or unverified. Preserve original evidence and report redacted copies where needed. Work within the authorized environment; do not silently expand to external targets.

Sources

Original OSA workflow and examples. Primary references are linked in the bundled workflow reference, so they remain available when this skill is installed separately. No third-party skill collection or rule pack is vendored.

Files

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.

Changes

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.

  1. 1mo ago First seen · 40 lines · 44 tokens per session scan A b84a18a6c28c

Subscribe to this mod's changes

network-defense is a skill published in the GitHub repository Miosa-osa/OSA (78 stars, last pushed 11d ago), licensed Apache-2.0. It adds 44 tokens to every session and 429 once invoked, about $0.0002 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 2026-09-15.