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First formal security scanner for AI agent skills & plugins. Static analysis, supply chain verification, SBOM generation. 22 frameworks supported including MCP, LangChain, CrewAI.

24 starsPython

SkillFortify, a formal verification for AI agent skills

by varunpratap369·Feb 26, 2026·2 points·2 comments

AI Analysis

●●SolidBig BrainNiche Gem

Formal verification for agent skills when heuristic scanners always fail.

Strengths
  • Mathematical soundness guarantees via five proven theorems, not heuristic guessing
  • Zero false positives on benchmark suite, fail-safe architecture blocks by default
  • Multi-format skill detection (CLI, discovery, lock-file reproducibility)
Weaknesses
  • Narrow TAM: only matters if you deploy untrusted third-party skills to agents
  • Early stage with minimal adoption signals, no public benchmarks against real malicious skills
Category
Target Audience

AI agent platform operators, security teams in compliance-heavy environments

Similar To

VirusTotal · YARA rules · LLM-as-judge pattern matching

Post Description

Hi HN,

In January 2026, 1,200 malicious skills infiltrated the OpenClaw agent marketplace (ClawHavoc campaign). A month later, researchers catalogued 6,487 malicious agent tools that VirusTotal cannot detect. The first agent-software RCE was assigned CVE-2026-25253.

The response: a dozen heuristic scanning tools (pattern matching, LLM-as-judge, YARA rules). They all carry the same caveat: "no findings does not mean no risk."

SkillFortify takes a different approach. Instead of checking for known bad patterns, it formally verifies what a skill CAN do against what it CLAIMS to do. Five mathematical theorems guarantee soundness -- if SkillFortify says a skill is safe, it provably cannot exceed its declared capabilities.

What it does: - skillfortify scan . -- discover and analyze all skills in a project - skillfortify verify skill.md -- formally verify against capability declaration - skillfortify lock -- generate skill-lock.json for reproducible configs - skillfortify trust skill.md -- compute trust score (provenance + behavior) - skillfortify sbom -- CycloneDX 1.6 Agent Skill Bill of Materials

Supports Claude Code skills, MCP servers, and OpenClaw manifests.

Evaluated on 540 skills (270 malicious, 270 benign): F1=96.95%, zero false positives.

Paper: [ZENODO_DOI_URL] Install: pip install skillfortify Code: https://github.com/varun369/skillfortify

Built as part of the AgentAssert research suite. Happy to answer questions about the formal model, threat landscape, or benchmark methodology.

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