install-hooks

name	install-hooks
description	Install ggshield as a hook so secrets are caught before they leak. Covers git hooks (pre-commit and pre-push) that block secrets from entering git history, and AI-assistant hooks (claude-code, codex, copilot, cursor, vscode) that scan an AI coding tool's prompts, actions, and outputs in real time. Use when asked to install Claude Code, Cursor, Copilot, or git hooks, or to block secrets from being committed or pushed.
metadata	{"version":"0.5.0"}

ggshield — Install Hooks

Overview

ggshield install wires ggshield in as a hook so hardcoded secrets are caught before they leak. This is the prevention layer — the reactive skills (scan-secrets, scan-machine, check-hmsl) find secrets that already exist; this one stops new ones at the door.

It installs two distinct families of hook:

• Git hooks — pre-commit / pre-push. Catch a secret as it is committed or pushed and block the git operation, so it never enters history.
• AI-assistant hooks — claude-code, codex, copilot, cursor, vscode. Register ggshield inside an AI coding tool so it scans the tool's prompts, actions, and outputs in real time: it scans your prompt before it reaches the model, scans commands, file reads, and MCP calls before the agent runs them, and scans outputs — blocking the prompt or action when a secret is found.

Both families install local (this project only) or global (all projects). Global is system-modifying — get explicit consent first.

When to Use

Install a hook when:

• The user asks to "install Claude hooks", "add a Cursor hook", "set up Copilot/Codex secret scanning", or otherwise wants their AI coding tool to stop secrets — that is the AI-assistant family.
• The user asks to "block secrets", "add a pre-commit hook", "stop secrets being committed or pushed", or "prevent this from happening again" after a secret was found — that is the git family.
• Setting up a new repo or hardening a machine and you want secret prevention from day one.

Do not use this skill to scan code that already exists — that is scan-secrets. A hook only guards future commits, pushes, or AI-tool interactions.

Which hook do you want?

ggshield install covers two families. Route by what the user said — do not guess across families:

The request mentions…	Install this family	Hook type
"Claude" / "Claude Code"	AI-assistant	claude-code
"Cursor"	AI-assistant	cursor
"Copilot" / "VS Code"	AI-assistant	copilot / vscode
"Codex"	AI-assistant	codex
"AI assistant" / "agent" hook generically	AI-assistant	ask which tool
"pre-commit" / "pre-push" / "git hook"	git	pre-commit / pre-push
"block secrets from being committed / pushed", "stop secrets entering history"	git	pre-commit / pre-push

If the request is bare — e.g. "install hooks" with no family signal — STOP and ask which family before running anything. Present the two one-liners:

• Git hook — blocks secrets from entering this repo's git history (on commit or push).
• AI-assistant hook — makes your AI coding tool (Claude Code, Cursor, Copilot, Codex) scan its prompts and actions for secrets in real time.

Once the family is clear, walk the within-family choices under Choosing your hook.

Onboarding (first use)

Prerequisites

Every hook calls the GitGuardian API to scan content, so ggshield must be installed and authenticated before any hook will work. An unauthenticated hook fails on every commit or AI-tool action.

• ggshield --version must succeed. AI-assistant hooks need ggshield 1.49.0+ (1.51.0+ for codex).
• ggshield api-status must report a working API key.
• For an AI-assistant hook, the target tool (Claude Code, Cursor, Copilot/VS Code, Codex) must itself be installed — the hook is written into that tool's config.

Setup

If either check fails, complete the setup steps in references/ggshield-cli-setup.md (install ggshield, then ggshield auth login) before installing any hook.

Choosing your hook

Once the family is settled, walk the user through the within-family choices. Do not assume a default — present the trade-offs and let the user choose.

Git hooks

1. Stage — pre-commit or pre-push?

Stage	Catches	Trade-off
pre-commit	Earliest — blocks the git commit itself	Tightest. Cannot create even a local commit containing a secret.
pre-push	Before anything leaves the machine	Allows local WIP commits with secrets; only blocks on push.

2. Scope — local or global?

Scope	Applies to	Trade-off
--mode local	The current repository only	Contained, easy to reason about and remove.
--mode global	Every repo cloned/init'd afterward (git template dir)	Maximum coverage. Modifies the user's global git config — get explicit consent.

AI-assistant hooks

Scope — local or global? Same present-the-choice discipline as git hooks.

Scope	Applies to	Writes to (Claude Code example)
--mode local	The current project only	the project's .claude/settings.json
--mode global	All projects, for this user	the user-level ~/.claude/settings.json

Global mode is system-modifying for both families. Confirm with the user before installing a global hook; never install one silently.

Commands

Pick the family and combination the user chose.

Git hooks

# Local pre-commit hook (this repo only)
ggshield install -m local -t pre-commit

# Local pre-push hook
ggshield install -m local -t pre-push

# Global pre-commit hook (all future repos) — only after explicit user consent
ggshield install -m global -t pre-commit

AI-assistant hooks

# Claude Code hook, this project only
ggshield install -m local -t claude-code

# Cursor hook, all projects (user-level) — system-modifying, confirm first
ggshield install -m global -t cursor

# Other tools: -t copilot, -t vscode, -t codex

Which file each AI-assistant hook writes:

Tool	-t value	Config file
Claude Code	claude-code	.claude/settings.json (local) or ~/.claude/settings.json (global)
Cursor	cursor	.cursor/hooks.json
GitHub Copilot / VS Code	copilot / vscode	VS Code settings
Codex	codex	~/.codex/hooks.json

Useful flags (both families):

• -f, --force — overwrite an existing hook script/config entry of the same type.
• -a, --append — append ggshield to an existing hook instead of overwriting. Use when the repo or tool already has a hook you must not clobber.

Verify the install

After running ggshield install, confirm it landed:

1. The command exited 0.
2. The hook is present:
   • git, local: .git/hooks/pre-commit or .git/hooks/pre-push in the repo.
   • git, global: the script is written into git's template directory (git config --get init.templateDir).
   • AI-assistant: the tool's config file now references ggshield (e.g. a ggshield entry in .claude/settings.json, .cursor/hooks.json, or ~/.codex/hooks.json).

This confirms installation, not live detection. It does not scan existing code or prove a real secret would be caught — it proves the hook is wired in. To scan code you already have, use the scan-secrets skill.

Handling a blocked commit or action

When a git hook fires, ggshield prints the detected secret's type and location and aborts the git commit (pre-commit) or git push (pre-push). When an AI-assistant hook fires, it blocks the prompt or the agent's action before it runs. Either way the content has not reached any remote — this is the easiest case to remediate, the pre-leak track:

1. Remove or replace the offending secret in the working tree or prompt (move it to an environment variable, a secrets manager, or an untracked .env that is gitignored).
2. Re-stage and commit again, or re-issue the prompt. The hook re-runs and passes.

No rotation is required — the secret never left your perimeter, so it has not leaked.

If the workspace has a custom remediation workflow, ggshield (≥ 1.30.0) prints the organization's own remediation message in the block output (configured per touchpoint under GitGuardian → Remediation workflow → Pre-commit / Pre-push / Pre-receive). That message is the customer's security team's process and takes the lead — surface it to the user verbatim as the primary guidance, then follow the remove-and-recommit steps above to fill in around it. Do not replace it with generic advice.

If, instead, you discover a secret that is already in git history (committed before the hook existed, or already pushed), that is a different, harder situation: the secret is exposed and must be treated as compromised. Use the scan-secrets skill, which carries the full remediation doctrine for secrets that are already in history or already public.

Best Practices

• Route by family first. If the user named an AI tool (Claude, Cursor, Copilot, Codex), install that AI-assistant hook — not a git pre-commit hook. If the request is bare "install hooks", ask which family before acting.
• Prefer pre-commit for the strongest git guarantee; offer pre-push when the user wants to keep local WIP commits unblocked. State the trade-off rather than choosing for them.
• Get explicit consent before global mode (either family) — it changes user-level config.
• Use --append, not --force, when a hook already exists, unless the user confirms the existing hook is disposable. --force overwrites it.
• A hook is not a substitute for scan-secrets. It guards future commits, pushes, and AI-tool interactions only; existing code and history still need a scan.
• Never echo secret values. When reporting a block, report type, file, and line — not the secret itself.

Troubleshooting

• Every commit or AI action fails with an auth/API error. The hook needs an authenticated ggshield. Run ggshield api-status; if it fails, complete the setup in references/ggshield-cli-setup.md.
• ggshield install says a hook already exists. Re-run with -a, --append to add ggshield alongside the existing hook, or -f, --force to replace it (destructive — confirm first).
• The AI-assistant hook does nothing. Confirm the target tool is installed and that the expected config file was written (.claude/settings.json, .cursor/hooks.json, ~/.codex/hooks.json, or VS Code settings); confirm ggshield 1.49.0+ (1.51.0+ for codex).
• A git hook does not run on commit. Confirm the script is executable and present at .git/hooks/<type>; for global mode confirm git config --get init.templateDir points where the hook was written and that the repo was created/cloned after the global install.
• Need to bypass a git hook once (emergency). git commit --no-verify skips hooks. Use only when you are certain there is no secret; it defeats the protection.
• Removing a hook. Delete the hook script from .git/hooks/ (local) or the template dir (global); for AI-assistant hooks, remove the ggshield entry from the tool's config file. There is no ggshield uninstall.