appsec-review

A focused application-security review guide for examining newly introduced vulnerabilities in a code change. Application security means protecting software from attacks involving inputs, permissions, data, and trust boundaries.

In plain words
What is it for?
Use it to review a pull request, branch, commit range, or path for issues such as injection, broken authorization, unsafe parsing, uncontrolled outbound requests, and data exposure.
Why use it?
It concentrates on high-confidence, exploitable problems instead of producing a noisy list of speculative concerns.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/agentic-dev3o/devx-plugins/appsec-review
Any agent
npx skills add agentic-dev3o/devx-plugins --skill appsec-review
Clone the repo
git clone --depth 1 https://github.com/agentic-dev3o/devx-plugins

Made for: Claude Code, Codex.

Per session 69 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,284 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00069 $0.01284
Opus 5 $0.00034 $0.00642
Sonnet 5 $0.00014 $0.00257
Haiku 4.5 $0.00007 $0.00128

Measured 2d ago against content hash 0393bc58f4b4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

appsec-review 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 2d 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.

plugins/qa/skills/appsec-review/SKILL.md · 98 lines

How it starts

The opening of the file, as written. The whole thing — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Application Security Review

Target: $ARGUMENTS (optional PR number, branch, commit range, or path; default to the current branch against the remote default branch)

Objective

Review only newly introduced application-layer vulnerabilities in the requested change set. Optimize for high-confidence, exploitable findings with real attacker value. Think in terms of trust boundaries, attacker-controlled inputs, privilege changes, unsafe parsing, outbound request control, data exposure, and framework-specific behavior across TypeScript, Node.js, Python, Rust, and modern web stacks.

Favor signal over coverage. Missing a speculative issue is better than shipping a noisy report.

Workflow

Progress checklist:

Application Security Review:
- [ ] Step 1: Resolve the review scope
- [ ] Step 2: Build repository security context
- [ ] Step 3: Generate candidate vulnerabilities
- [ ] Step 4: Filter false positives in parallel
- [ ] Step 5: Publish the final markdown report

Step 1: Resolve the Review Scope

  • If $ARGUMENTS looks like a PR number and GitHub context is available, gather the PR metadata first and review that diff.
  • Otherwise resolve the local review base from origin/HEAD. If the default branch is unclear, inspect git remote show origin.
  • Capture the complete review context:
    • git status
    • git diff --name-only <base>...HEAD
    • git log --no-decorate <base>...HEAD
    • git diff <base>...HEAD
  • Use git show <commit> when a suspicious commit needs narrower intent or before/after context.
  • If remote comparison is unavailable, fall back to staged plus unstaged local diff and say so explicitly in the review setup.

Step 2: Build Repository Security Context

  • Read adjacent code instead of reviewing the raw diff in isolation.
  • Identify the stack, auth model, tenant model, validation patterns, templating paths, serializers, and secret-handling conventions used near the changed files.
  • Compare the new code against nearby secure patterns before declaring a finding.
  • Load references/review-playbook.md for threat-model questions, attack-surface coverage, and stack-specific heuristics.

Read the full file on GitHub · 98 lines

Files

What ships with it

3 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. 2d ago First seen · 98 lines · 69 tokens per session scan A 0393bc58f4b4

Subscribe to this mod's changes

appsec-review is a skill published in the GitHub repository agentic-dev3o/devx-plugins (11 stars, last pushed 14d ago), licensed MIT. It adds 69 tokens to every session and 1,284 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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