Skarn
ChatGPT pluginAI session security scanner
Skarn is a command-line security scanner for AI coding sessions. The audit skill, skarn-audit, teaches the model to run the skarn CLI on this machine and act on what it reports.
The skill runs two passes. skarn assess reads the session transcripts that AI coding assistants have already written to disk and reports leaked credentials, prompt injection, exfiltration attempts, and the chains that connect them; each finding carries the standards mappings that apply to it, drawn from MITRE ATLAS, the OWASP Top 10 for LLM Applications 2025, the OWASP Agentic Top 10, and CWE. skarn vet reads the assistant configuration files on the same machine and reports risky declarations: hooks, MCP servers, and permission grants that could run remote code or send data off the machine.
Both passes run entirely on this machine and make no network call. Neither modifies a session transcript or a configuration file, and every credential value in the output is masked, so a finding names a rule and a masked preview and never the credential itself. Skarn surfaces findings and does not rotate a credential or edit a configuration on its own: the skill proposes, and the user decides. The one thing the skill can write is a baseline entry recording a finding the user has explicitly confirmed as a false positive.
The skill runs a local shell command, so it is offered in Codex. It does not carry the skarn binary, which is installed separately:
brew install skarn-security/tap/skarn npm install -g @skarn-security/skarn Release binaries: https://github.com/skarn-security/skarn-dist/releases/latest
When the binary is not installed, the skill says how to install it and stops rather than inventing a result. skarn assess and skarn vet need no account and no license.
Skarn also ships a hook that inspects a tool call before Codex runs it, and a skill that reconstructs recent work from session history. Both are distributed through the plugin marketplace at https://github.com/skarn-security/agent-guard.
Documentation: https://getskarn.com/integrations/ Support: hello@getskarn.com
- Featured
- No
not on the featured shelf
Movement
From our daily snapshots over the last 30 days.
Rank by placement
Rank in Security
In its category
How this plugin compares with others in the same category. Positions are counted within the category, not across the whole directory.
Security46th of 66 by placement
| # | Plugin | Position | 7d |
|---|---|---|---|
| 44 | #5532 | 83places up | |
| 45 | #5604 | 122places down | |
| 46 | #5738 | 93places down | |
| 47 | #6042 | 51places up | |
| 48 | #6053 | 4places up |
Example prompts
- “Scan my AI coding sessions from the last 24 hours with skarn and tell me what to rotate first.”
- “Vet my assistant configuration with skarn and list any hook or MCP server that could send data off this machine.”
- “Run skarn assess here and summarize the highest-severity findings without revealing any secret.”
Skills
skarn-audit
Audit this machine's AI coding sessions and assistant configs with skarn. Use when the user says scan this with skarn, run skarn, or skarn audit; asks whether a secret leaked into an AI coding session; wants an assistant config (hooks, MCP servers, permissions, plugins) vetted; or asks whether a Claude Code, Codex, Cursor, Copilot, or Gemini setup is safe. Not for scanning a source tree or repository for secrets, and not a code review. Runs skarn assess and skarn vet offline and reads only redacted output.
- Categories
- Made by
- Skarn Software OÜ · Website
- Sign-in
- On Install
- Capabilities
- Scan AI coding sessions for leaked credentials, Vet assistant hooks, MCP servers and permission grants
- Availability
- Available
- Version
- 0.27.0
- Keywords
- security, secrets, credential-leak, ai-coding-sessions, audit, codex
- Created
- August 30, 2026
- More info
- Sponsorship
- Promote this plugin