Open-source guardrail
Deleting Windows shadow copies or recovery data
AgentTrail Guard blocks this by default: the call never runs, and your coding agent is told which guardrail stopped it.
- Default action
- Block
- Severity
- Critical severity
- Library version
- 0.2.1 · Sep 29, 2026
What it does
What it catches, and what it misses
Written into the rule itself, next to what it matches, so you can judge it before you trust it.
Deletes Windows shadow copies, the backup catalog, or the recovery boot entry — the standard opening move of ransomware, because it removes the only local route back from an encrypted disk. There is no legitimate reason for a coding agent to run any of it. Does NOT match the read-only siblings (vssadmin list shadows, wbadmin get status, bcdedit /enum), which are reasonable while diagnosing a backup. Windows-only by nature; the equivalent on macOS (tmutil delete) is not covered. A quoted MENTION is not a use: a search, a git commit -m message, an echo or a curl --data body that only names this command is left alone. That holds only while every shell metacharacter stays inside the quotes, so git commit -m "x" && … is still caught; and the carrier must be the first word, so sudo grep … is not exempt.
Examples
Tested on every build
The rule must match every command on the left and none on the right, or the library does not build. Catching the real thing is easy; staying quiet on the near-miss is the hard part.
Catches (4)
- PowerShellvssadmin delete shadows /all /quiet
- PowerShellwbadmin delete catalog -quiet
- PowerShellbcdedit /set {default} recoveryenabled no
- wmic shadowcopy delete
Stays quiet on (8)
- git commit -m "docs: explain vssadmin delete shadows /all /quiet"
- grep -rn "vssadmin delete shadows /all /quiet" docs/
- echo "never run vssadmin delete shadows /all /quiet"
- curl --data "we ran vssadmin delete shadows /all /quiet" https://api.example.com/comments
- PowerShellvssadmin list shadows
- PowerShellwbadmin get status
- PowerShellbcdedit /enum
- PowerShellGet-ComputerRestorePoint
In your agent
What "block" means in each app
The guard runs as a hook in each app, and each app gives a hook different powers. Here is what this rule's default action does in each one.
- Claude Code
- The call never runs, and the agent is told which guardrail stopped it.
- Cursor
- The call never runs. Cursor shows no reason of its own, so the agent retells the guardrail's message in its own words.
- Codex CLI
- The command never runs, and Codex prints the guard's reason on screen.
Each app hands the guard a different set of calls: in a Cursor sandbox run mode, for one, some terminal commands run without reaching the guard at all. Read the notes for Cursor and for Codex CLI before you rely on a rule there.
Make it yours
Change what it does in one command
Turn it off, change its action, or silence it on one command shape. The narrow one is allow: the rule keeps catching everything else.
Run it locally
Put these guardrails in front of your agent.
AgentTrail Guard is free and open source. It checks every command and file change against the whole library before your agent runs it, on your machine, with no account.
npm i -g @agenttrail/guard