Hook Development for Claude Code Plugins
anthropics/claude-plugins-official
Explains how to write Claude Code plugin hooks, both prompt-based checks and bash commands, for events such as PreToolUse, Stop and SessionStart.
Fact-forcing gate that blocks Edit/Write/Bash (including MultiEdit) and demands concrete investigation (importers, data schemas, user instruction) before allowing the action.
Custom licenceAuto-check passed
Install Gateguard
$ npx skills add Sidiora-Labs/centra-llm-agents --skill gateguard -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install Sidiora-Labs/centra-llm-agents gateguard --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/Sidiora-Labs/centra-llm-agents.git skills-src && mkdir -p .claude/skills && cp -r skills-src/protocol/skills/gateguard .claude/skills/gateguard && 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 "gateguard" agent skill from https://github.com/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguard into .claude/skills/gateguard/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gateguard", 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/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguardType 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 Sidiora-Labs/centra-llm-agents --skill gateguard -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install Sidiora-Labs/centra-llm-agents gateguard --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Sidiora-Labs/centra-llm-agents.git skills-src && mkdir -p .agents/skills && cp -r skills-src/protocol/skills/gateguard .agents/skills/gateguard && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "gateguard" agent skill from https://github.com/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguard into .agents/skills/gateguard/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gateguard", 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 Sidiora-Labs/centra-llm-agents --skill gateguard -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install Sidiora-Labs/centra-llm-agents gateguard --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Sidiora-Labs/centra-llm-agents.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/protocol/skills/gateguard .cursor/skills/gateguard && 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 "gateguard" agent skill from https://github.com/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguard into .cursor/skills/gateguard/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gateguard", 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/Sidiora-Labs/centra-llm-agents.git --path protocol/skills/gateguard--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 Sidiora-Labs/centra-llm-agents --skill gateguard -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install Sidiora-Labs/centra-llm-agents gateguard --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Sidiora-Labs/centra-llm-agents.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/protocol/skills/gateguard .gemini/skills/gateguard && 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 "gateguard" agent skill from https://github.com/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguard into .gemini/skills/gateguard/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gateguard", 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 Sidiora-Labs/centra-llm-agents gateguardInstalls 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 Sidiora-Labs/centra-llm-agents --skill gateguard -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/Sidiora-Labs/centra-llm-agents.git skills-src && mkdir -p .github/skills && cp -r skills-src/protocol/skills/gateguard .github/skills/gateguard && 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 "gateguard" agent skill from https://github.com/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguard into .github/skills/gateguard/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gateguard", 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 Sidiora-Labs/centra-llm-agents --skill gateguard -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install Sidiora-Labs/centra-llm-agents gateguard --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/Sidiora-Labs/centra-llm-agents.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/protocol/skills/gateguard .opencode/skills/gateguard && 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 "gateguard" agent skill from https://github.com/Sidiora-Labs/centra-llm-agents/tree/main/protocol/skills/gateguard into .opencode/skills/gateguard/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "gateguard", 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
gateguard- GitHub stars
- 116
- Used in
- 1 other repo
- Token cost
- ~1.1k tokens
- SKILL.md length
- 404 words
- Files
- 2
- Skills in repo
- 13
- Repo updated
- First seen
- Licence
- Custom licence
At a glance
Fact-forcing gate that blocks Edit/Write/Bash (including MultiEdit) and demands concrete investigation (importers, data schemas, user instruction) before allowing the action.
- SKILL.md covers When to Activate, Core Concept, Evidence and Gate Types, plus 4 more sections
- Calls git and pip
What it does
Gateguard is an agent skill from Sidiora-Labs/centra-llm-agents. Fact-forcing gate that blocks Edit/Write/Bash (including MultiEdit) and demands concrete investigation (importers, data schemas, user instruction) before allowing the action. Measurably improves output quality by +2.25 points vs ungated agents.
Its SKILL.md is about 1.1k tokens, which your agent loads only when the skill is triggered. The skill folder holds 1 other file.
It works with Bash. The repository describes itself as: A stateful AI operating system for serious, long-horizon work.
Example prompts
- “/gateguard”
Requirements
- Python 3
What it can do on your machine
Read from SKILL.md and the folder at commit 01c6aef. 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:
gitpip
From the folder's file list and the shell code blocks in SKILL.md.
Network
No URLs in SKILL.md. Its commands use git and pip, 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
Gateguard loads about 1.1k tokens when it runs. Until then it costs about 64 tokens; SKILL.md has 404 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 404 words (~1,132 tokens).
“A PreToolUse hook that forces Claude to investigate before editing. Instead of self-evaluation ("are you sure?"), it demands concrete facts. The act of investigation creates awareness that self-evaluation never did.”
- name
- gateguard
- origin
- community
Files
SKILL.md and 1 other file in protocol/skills/gateguard of Sidiora-Labs/centra-llm-agents.
- SKILL.md
- SKILL.mtx
Open the folder on GitHubat commit 01c6aef
Used in 1 other repository
We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in Sidiora-Labs/centra-llm-agents, which our catalogue first saw on October 7, 2026.
Compare with similar skills
Gateguard 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 |
|---|---|---|---|---|---|---|
| Gateguard this skillSidiora-Labs/centra-llm-agents | 116 | 1 repos | ~1.1k | Automated safety check: Pass | Custom licence | |
| Hook Development for Claude Code Pluginsanthropics/claude-plugins-official | 38k | 10 repos | ~4.1k | Automated safety check: Notes | Apache-2.0 | |
| Plugin Settings Patternanthropics/claude-plugins-official | 38k | 7 repos | ~3k | Automated safety check: Pass | Apache-2.0 | |
| E2Ecallstack/react-native-pager-view | 3.4k | 3 repos | ~2.1k | Automated safety check: Pass | MIT | |
| Mole Bug Patternstw93/Mole | 70k | — | ~2k | Automated safety check: Pass | GPL-3.0 | |
| Neat-Freak Knowledge CloseoutKKKKhazix/khazix-skills | 21k | — | ~1.9k | Automated safety check: Pass | MIT |
Similar skills
- Official
- Official
Plugin Settings Pattern
anthropics/claude-plugins-official
Shows how Claude Code plugins keep per-project settings and state in .claude/plugin-name.local.md files with YAML frontmatter and a markdown body.
E2E
callstack/react-native-pager-view
Agentic end-to-end tests with e2e, the e2e runner. An agent skill from callstack/react-native-pager-view.
Mole Bug Patterns
tw93/Mole
A catalog of recurring bug shapes in the Mole Mac cleaner, used to review safety-sensitive diffs for deletion safety, unbounded commands, shell traps and weak tests.
Neat-Freak Knowledge Closeout
KKKKhazix/khazix-skills
Brings project docs, agent rule files, authorized memory and leftover workspace files back in line with what the code and runtime actually do at the end of a work session.
CCPM Project Management
automazeio/ccpm
Runs a spec-driven workflow from PRD to epic to GitHub issues to parallel agents, with status, standup and blocked-work reports from bundled scripts.
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Related
Works with
Questions about Gateguard
What does Gateguard do?
Fact-forcing gate that blocks Edit/Write/Bash (including MultiEdit) and demands concrete investigation (importers, data schemas, user instruction) before allowing the action. Gateguard is an agent skill from Sidiora-Labs/centra-llm-agents. Fact-forcing gate that blocks Edit/Write/Bash (including MultiEdit) and demands concrete investigation (importers, data schemas, user instruction) before allowing the action.
How do I install Gateguard in Claude Code?
Run `npx skills add Sidiora-Labs/centra-llm-agents --skill gateguard -a claude-code`. Or copy the skill folder (protocol/skills/gateguard in Sidiora-Labs/centra-llm-agents) into .claude/skills/gateguard in your project. Claude Code loads it when a task matches its description.
How do I install Gateguard in Codex?
Run `npx skills add Sidiora-Labs/centra-llm-agents --skill gateguard -a codex`. Or copy the skill folder (protocol/skills/gateguard in Sidiora-Labs/centra-llm-agents) into .agents/skills/gateguard in your project. Codex loads it when a task matches its description.
Can I use Gateguard 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 Sidiora-Labs/centra-llm-agents --skill gateguard -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/gateguard, .gemini/skills/gateguard, .github/skills/gateguard and .opencode/skills/gateguard in your project.
What does Gateguard need to run?
Going by SKILL.md and its folder, Gateguard needs the command-line tools its instructions call (git and pip). Our summary lists: Python 3.
Does Gateguard access the network?
SKILL.md contains no URLs. Its commands use git and pip, which can reach the network depending on how they are called. This is read from the text; nothing was executed.
Is Gateguard 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 Gateguard use?
Gateguard 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 Gateguard use?
About 1.1k tokens (SKILL.md is roughly 4.5k 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 Gateguard?
Skills that share tags, products or a category with Gateguard: Hook Development for Claude Code Plugins (anthropics/claude-plugins-official, 38k stars), Plugin Settings Pattern (anthropics/claude-plugins-official, 38k stars), E2E (callstack/react-native-pager-view, 3.4k stars) and Mole Bug Patterns (tw93/Mole, 70k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
Who maintains Gateguard?
Sidiora-Labs (a GitHub organization) maintains it in Sidiora-Labs/centra-llm-agents, which has 116 GitHub stars. The repository holds 13 skills in this directory. The repository was last updated on September 18, 2026.
Source: Sidiora-Labs/centra-llm-agents on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.