What is security-default-review-for-web-apps?

A practical first-pass security review for web applications, focused on where users, secrets, and sensitive actions meet.

Use it to list public inputs and privileged actions, inspect trust boundaries, and decide whether a more specific security review is needed.

It helps find the main security risk before coding fixes, such as exposed secrets, weak permissions, or unsafe handling of user input.

security-default-review-for-web-apps — Skill by andrewsrigom

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 andrewsrigom/agent-skills --skill security-default-review-for-web-apps

Clone the repo

git clone --depth 1 https://github.com/andrewsrigom/agent-skills

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/security-default-review-for-web-apps/github.svg)](https://agentmods.dev/skills/andrewsrigom/agent-skills/security-default-review-for-web-apps)

Your own site

<a href="https://agentmods.dev/skills/andrewsrigom/agent-skills/security-default-review-for-web-apps"><img src="https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/security-default-review-for-web-apps/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/andrewsrigom/agent-skills/security-default-review-for-web-apps"><img src="https://agentmods.dev/badge/skills/andrewsrigom/agent-skills/security-default-review-for-web-apps.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 54 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 590 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.

Model	Per session	Once invoked
Fable 5.1	$0.00054	$0.00590
Opus 5.5	$0.00022	$0.00236
Sonnet 5.5	$0.00011	$0.00118
Haiku 4.5	$0.00005	$0.00059

Measured 2mo ago against content hash 496fef4b2e9e, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

security-default-review-for-web-apps 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 2mo 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.

security/security-default-review-for-web-apps/SKILL.md · 75 lines

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.

Security Default Review For Web Apps

Use this skill when the task is to find the highest-risk web security boundary before the team starts patching randomly.

Scope

high-level security review for web apps
deciding whether the main risk is secrets, authorization, or input handling
identifying public input and privileged actions
routing to narrower security skills

Routing cues

security review, secure by default, trust boundary, secret exposure, authz review, dangerous sink, or “what is the main risk here” -> use this skill
if the core issue is client vs server boundary or secret handling -> use security-client-server-boundary-and-secret-exposure
if the core issue is permissions, actor trust, or multi-tenant access -> use security-authz-and-trust-boundaries
if the core issue is untrusted input reaching dangerous sinks -> use security-input-validation-and-dangerous-sinks

Default path

List the public inputs, authenticated actors, and privileged actions.
Identify where secrets or sensitive data live.
Mark the trust boundaries:
- browser vs server
- unauthenticated vs authenticated
- authenticated vs authorized
- internal service vs external caller
Pick the highest-risk boundary.
Route the fix through the narrower security skill that owns that boundary.

When to deviate

Stay at the overview level only when the user truly needs a triage map rather than a fix.
Escalate beyond these skills when the issue is infrastructure, cryptography, or compliance-specific rather than app-boundary specific.

Guardrails

Do not call this a full security audit.
Prioritize exploitable trust-boundary mistakes over broad best-practice checklists.
Treat the browser as untrusted by default.
Separate authentication, authorization, and input safety clearly.

Avoid

giving equal weight to every theoretical issue
focusing only on XSS and SQL injection while missing authz failures or secret leaks
trusting UI checks as a security boundary
calling a review complete without naming the highest-risk surface

Read the full file on GitHub · 75 lines

Files

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.

references/default-review-map.md 518 B

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.

2mo ago First seen · 75 lines · 54 tokens per session scan A 496fef4b2e9e

Subscribe to this mod's changes

security-default-review-for-web-apps is a skill published in the GitHub repository andrewsrigom/agent-skills (2 stars, last pushed 7mo ago), licensed MIT. It adds 54 tokens to every session and 590 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 2026-08-31.