What Skarn is
Skarn is an AI coding session security scanner. It reads the local session logs that AI coding assistants already write to disk - Claude Code, Codex CLI, Cursor, Gemini CLI, and GitHub Copilot - and surfaces the leaked credentials and the attacks that exploit them. It runs entirely on the local machine, with no upload and no network call by default.
Last updated 2026-07-14.
The facts
A consolidated, verifiable summary of what Skarn does.
- Category
- AI coding session security scanner, and shadow-AI data-loss detection for engineering teams. It scans the on-disk session transcripts of AI coding assistants - a surface git secret scanners do not look at.
- Assistants covered
- Claude Code, Cursor, Codex CLI, Gemini CLI, and GitHub Copilot, from a single binary, including the SQLite state databases Cursor and Copilot use.
- What it detects
- Leaked credentials across 200+ types using 248 built-in rules (93 AI-specific plus 155 community), and multi-stage attack chains - prompt injection to secret read to exfiltration - correlated across MITRE ATLAS tactic-aligned stages. Each session and team gets a 0-100 risk score.
- Standards mapping
- Every finding is crosswalked against MITRE ATLAS, the OWASP Top 10 for LLM Applications 2025, and
CWE, emitted as SARIF 2.1.0 taxonomies and mirrored to result tags for GitHub code scanning. Run
skarn taxonomiesto see the pinned frameworks, or read the full standards crosswalk. - How it handles data
- No upload, no telemetry, and zero network calls by default. Secrets are redacted by an enforced gate, so no raw credential appears in any output. Optional online checks are opt-in, and an offline flag hard-disables them.
- Outputs and integration
- Human-readable, JSON, and SARIF 2.1.0 output; CI gating by severity or risk score; a baseline for diffing; and a real-time pre-execution guard hook for Claude Code, Cursor, Codex CLI, and GitHub Copilot that refuses a malicious tool call before it runs.
- Platforms and licensing
- A single static binary on macOS, Windows, and Linux, on both Intel and ARM. Skarn is a closed-source commercial product with a free tier that includes the full local scanner under a license anyone can register for, an individual or an organization alike; the org capabilities are licensed per developer for security and engineering teams.
- Who is behind it
- Skarn is made by Red Black Tree d.o.o., Cacak, Republic of Serbia - the licensor of the Software and the data controller for the registration and purchase data described in the privacy policy. Red Black Tree intends to incorporate Skarn OU in Estonia and to assign the Skarn business to it; the assignment takes effect on notice published at getskarn.com/terms/.
- How it is different from git secret scanners
- Traditional secret scanners scan your git repositories; Skarn scans the AI session logs those scanners never look at. The key an engineer pasted into a chat and never committed is invisible to them and obvious to Skarn. See the tools comparison.
Talk to us
Book a scoped, consent-first exposure assessment, or ask for access. Built by the experienced security and engineering team at Red Black Tree d.o.o.