Defense-in-Depth Validation

Defense-in-Depth Validation is a skill for Claude Code from obra/clank. It costs 17 tokens per session (872 once invoked), scanned A, original, no licence file.

A validation method that checks data at every layer it passes through in a system.

In plain words
What is it for?
Adding checks across multiple processing layers so incorrect data is detected throughout the flow.
Why use it?
It helps catch invalid data near the point where it enters or changes, reducing bugs that appear later.

Skill for Claude Code

Written for Claude Code: when-to-use in frontmatter.

Good fit Adding checks across multiple processing layers so incorrect data is detected throughout the flow.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/obra/clank/defense-in-depth
View source ↗ obra/clank
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 obra/clank --skill defense-in-depth
Clone the repo
git clone --depth 1 https://github.com/obra/clank

Made for: Claude Code.

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 Defense-in-Depth Validation

README.md
[![agentmods](https://agentmods.dev/badge/skills/obra/clank/defense-in-depth.svg)](https://agentmods.dev/skills/obra/clank/defense-in-depth)
Your own site
<a href="https://agentmods.dev/skills/obra/clank/defense-in-depth"><img src="https://agentmods.dev/badge/skills/obra/clank/defense-in-depth.svg" alt="Measured on agentmods" height="20"></a>
Per session 17 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 872 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 unknown 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 $0.00017 $0.00872
Opus 5 $0.00009 $0.00436
Sonnet 5 $0.00003 $0.00174
Haiku 4.5 $0.00002 $0.00087

Measured 8d ago against content hash 5aaad215cf03, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

Defense-in-Depth Validation 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 8d 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.

skills/debugging/defense-in-depth/SKILL.md · 131 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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. 8d ago First seen · 131 lines · 17 tokens per session scan A 5aaad215cf03

Subscribe to this mod's changes

Defense-in-Depth Validation is a skill published in the GitHub repository obra/clank (41 stars, last pushed 11mo ago), with no licence file. It adds 17 tokens to every session and 872 once invoked, about $0.0001 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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