Defense In Depth Validation
secondsky/claude-skills
Validate at every layer data passes through to make bugs impossible.
A skill your agent uses when invalid data causes failures deep in execution, requiring validation at multiple system layers - validates at every layer data passes through to make bugs structurally…
Install Defense In Depth
$ npx skills add sandgardenhq/sgai --skill defense-in-depth -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install sandgardenhq/sgai defense-in-depth --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/sandgardenhq/sgai.git skills-src && mkdir -p .claude/skills && cp -r skills-src/cmd/sgai/skel/.sgai/skills/defense-in-depth .claude/skills/defense-in-depth && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "defense-in-depth" agent skill from https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depth into .claude/skills/defense-in-depth/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "defense-in-depth", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depthType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add sandgardenhq/sgai --skill defense-in-depth -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install sandgardenhq/sgai defense-in-depth --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sandgardenhq/sgai.git skills-src && mkdir -p .agents/skills && cp -r skills-src/cmd/sgai/skel/.sgai/skills/defense-in-depth .agents/skills/defense-in-depth && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "defense-in-depth" agent skill from https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depth into .agents/skills/defense-in-depth/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "defense-in-depth", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add sandgardenhq/sgai --skill defense-in-depth -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install sandgardenhq/sgai defense-in-depth --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sandgardenhq/sgai.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/cmd/sgai/skel/.sgai/skills/defense-in-depth .cursor/skills/defense-in-depth && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "defense-in-depth" agent skill from https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depth into .cursor/skills/defense-in-depth/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "defense-in-depth", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/sandgardenhq/sgai.git --path cmd/sgai/skel/.sgai/skills/defense-in-depth--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add sandgardenhq/sgai --skill defense-in-depth -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install sandgardenhq/sgai defense-in-depth --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sandgardenhq/sgai.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/cmd/sgai/skel/.sgai/skills/defense-in-depth .gemini/skills/defense-in-depth && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "defense-in-depth" agent skill from https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depth into .gemini/skills/defense-in-depth/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "defense-in-depth", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install sandgardenhq/sgai defense-in-depthInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add sandgardenhq/sgai --skill defense-in-depth -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/sandgardenhq/sgai.git skills-src && mkdir -p .github/skills && cp -r skills-src/cmd/sgai/skel/.sgai/skills/defense-in-depth .github/skills/defense-in-depth && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "defense-in-depth" agent skill from https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depth into .github/skills/defense-in-depth/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "defense-in-depth", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add sandgardenhq/sgai --skill defense-in-depth -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install sandgardenhq/sgai defense-in-depth --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sandgardenhq/sgai.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/cmd/sgai/skel/.sgai/skills/defense-in-depth .opencode/skills/defense-in-depth && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "defense-in-depth" agent skill from https://github.com/sandgardenhq/sgai/tree/main/cmd/sgai/skel/.sgai/skills/defense-in-depth into .opencode/skills/defense-in-depth/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "defense-in-depth", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
Facts
- Skill name
defense-in-depth- GitHub stars
- 137
- Used in
- 3 other repos
- Token cost
- ~970 tokens
- SKILL.md length
- 316 words
- Files
- 1
- Skills in repo
- 53
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
A skill your agent uses when invalid data causes failures deep in execution, requiring validation at multiple system layers - validates at every layer data passes through to make bugs structurally…
- Works in 4 steps: Trace the data flow - Where does bad… → Map all checkpoints - List every point… → Add validation at each layer - Entry,… → …
- Invalid data causes failures deep in execution
- SKILL.md covers Overview, Why Multiple Layers, The Four Layers and Applying the Pattern, plus 2 more sections
- Calls git
What it does
Defense In Depth is an agent skill from sandgardenhq/sgai. Use when invalid data causes failures deep in execution, requiring validation at multiple system layers - validates at every layer data passes through to make bugs structurally impossible
Its SKILL.md is about 970 tokens, which your agent loads only when the skill is triggered. It is a single SKILL.md file with no bundled scripts.
It sits in Security, covering Secure coding. It works with Git. The repository describes itself as: Sandgarden AI Software Factory.
When your agent uses it
- Invalid data causes failures deep in execution
- Requiring validation at multiple system layers - validates at every layer data passes through to make bugs structurally impossible
Example prompts
- “/defense-in-depth”
Workflow steps
4 steps, taken from the first numbered list in SKILL.md.
- Trace the data flow - Where does bad value originate? Where used?
- Map all checkpoints - List every point data passes through
- Add validation at each layer - Entry, business, environment, debug
- Test each layer - Try to bypass layer 1, verify layer 2 catches it
What it can do on your machine
Read from SKILL.md and the folder at commit 9efbb7b. It shows what the files ask for, not the result of running them.
Tool permissions
Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.
From allowed-tools in the SKILL.md frontmatter.
Runs code
Shell commands in SKILL.md call:
git
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use git, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Credentials
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Context cost
Defense In Depth loads about 970 tokens when it runs. Until then it costs about 51 tokens; SKILL.md has 316 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
Safety
Auto-check passed
The automated check found no risky patterns in SKILL.md.
Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
SKILL.md
Its licence (Custom licence) doesn't allow us to republish the file, so here is its outline and opening line. It has 316 words (~970 tokens).
“When you fix a bug caused by invalid data, adding validation at one place feels sufficient. But that single check can be bypassed by different code paths, refactoring, or mocks.”
- name
- defense-in-depth
Files
Just SKILL.md in cmd/sgai/skel/.sgai/skills/defense-in-depth of sandgardenhq/sgai.
Open the folder on GitHubat commit 9efbb7b
Used in 3 other repositories
We found 4 copies of this SKILL.md (exact, near-identical or edited) in other folders, from 3 other GitHub owners. This page covers the copy in sandgardenhq/sgai, which our catalogue first saw on October 7, 2026.
Compare with similar skills
Defense In Depth next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Defense In Depth this skillsandgardenhq/sgai | 137 | 3 repos | ~970 | Automated safety check: Pass | Custom licence | |
| Defense In Depth Validationsecondsky/claude-skills | 227 | — | ~1.3k | Automated safety check: Pass | MIT | |
| Thorough Code Reviewpretend1111/claude-desktop-app | 496 | 1 repos | ~502 | Automated safety check: Pass | Custom licence | |
| Security AuditTheDecipherist/claude-code-mastery | 551 | — | ~1.3k | Automated safety check: Notes | MIT | |
| Humble Header Report Analystrfc-st/humble | 379 | — | ~3.7k | Automated safety check: Pass | MIT | |
| Pre-Commit Security Scanzereight/gitlab-mcp | 2k | 1 repos | ~859 | Automated safety check: Notes | MIT |
Similar skills
Thorough Code Review
pretend1111/claude-desktop-app
Reviews code or recent changes for bugs, security issues, performance problems and maintainability, reporting findings by severity with the reason and a fix.
Security Audit
TheDecipherist/claude-code-mastery
Checks a codebase for hardcoded secrets, vulnerable dependencies, weak input handling, weak authentication and unsafe transport settings before deployment or merge.
Humble Header Report Analyst
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Parses reports from the humble HTTP security header analyzer and explains each finding with remediation steps for DevOps teams.
Pre-Commit Security Scan
zereight/gitlab-mcp
Runs a fast security sweep of recent code changes before a commit or PR, checking for leaked secrets, vulnerable dependencies, unsafe input handling and auth gaps.
DefectDojo Vulnerability Management
AgentSecOps/SecOpsAgentKit
Aggregates scanner results into DefectDojo, deduplicates findings, tracks remediation SLAs and prepares compliance reports across products and pipelines.
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Questions about Defense In Depth
What does Defense In Depth do?
A skill your agent uses when invalid data causes failures deep in execution, requiring validation at multiple system layers - validates at every layer data passes through to make bugs structurally…. Defense In Depth is an agent skill from sandgardenhq/sgai.
When should I use Defense In Depth?
Defense In Depth fits situations like: invalid data causes failures deep in execution; requiring validation at multiple system layers - validates at every layer data passes through to make bugs structurally impossible.
How do I install Defense In Depth in Claude Code?
Run `npx skills add sandgardenhq/sgai --skill defense-in-depth -a claude-code`. Or copy the skill folder (cmd/sgai/skel/.sgai/skills/defense-in-depth in sandgardenhq/sgai) into .claude/skills/defense-in-depth in your project. Claude Code loads it when a task matches its description.
How do I install Defense In Depth in Codex?
Run `npx skills add sandgardenhq/sgai --skill defense-in-depth -a codex`. Or copy the skill folder (cmd/sgai/skel/.sgai/skills/defense-in-depth in sandgardenhq/sgai) into .agents/skills/defense-in-depth in your project. Codex loads it when a task matches its description.
Can I use Defense In Depth in Cursor, Gemini CLI or GitHub Copilot?
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add sandgardenhq/sgai --skill defense-in-depth -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/defense-in-depth, .gemini/skills/defense-in-depth, .github/skills/defense-in-depth and .opencode/skills/defense-in-depth in your project.
What does Defense In Depth need to run?
Going by SKILL.md and its folder, Defense In Depth needs the command-line tools its instructions call (git).
Does Defense In Depth access the network?
SKILL.md contains no URLs. Its commands use git, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Defense In Depth safe to install?
Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.
What licence does Defense In Depth use?
Defense In Depth has a licence file (the repository's licence) that doesn't match a standard licence. Read it on GitHub before reusing the skill.
How many tokens does Defense In Depth use?
About 970 tokens (SKILL.md is roughly 3.9k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full.
What are the alternatives to Defense In Depth?
Skills that share tags, products or a category with Defense In Depth: Defense In Depth Validation (secondsky/claude-skills, 227 stars), Thorough Code Review (pretend1111/claude-desktop-app, 496 stars), Security Audit (TheDecipherist/claude-code-mastery, 551 stars) and Humble Header Report Analyst (rfc-st/humble, 379 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Defense In Depth?
sandgardenhq (a GitHub organization) maintains it in sandgardenhq/sgai, which has 137 GitHub stars. The repository holds 53 skills in this directory. The repository was last updated on September 21, 2026.
Source: sandgardenhq/sgai on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.