tessl-labs/skills-security-audit
Audit installed tessl skills for security risks and generate a formatted security report with per-skill risk levels and an overall project risk score
75
94%
Does it follow best practices?
Run evals on this skill
Adds up to 20 points to the overall score
View guide
Low
Low-risk findings worth noting
Low
Low-risk findings.
2 low severity findings. Worth noting, but not necessarily harmful.
W011: Third-party content exposure detected (indirect prompt injection risk).
What this means
The skill exposes the agent to untrusted, user-generated content from public third-party sources, creating a risk of indirect prompt injection. This includes browsing arbitrary URLs, reading social media posts or forum comments, and analyzing content from unknown websites.
Why it was flagged
The skill's SKILL.md Step 2 requires the agent to fetch and parse security pages from the public Tessl Registry (e.g., https://tessl.io/registry/... and https://tessl.io/registry/skills/github/...), using WebFetch to extract Snyk scores and findings that the agent then uses to form verdicts, so it clearly ingests untrusted third-party web content that could embed instructions or influence behavior.
W012: Unverifiable external dependency detected (runtime URL that controls agent).
What this means
The skill fetches instructions or code from an external URL at runtime, and the fetched content directly controls the agent’s prompts or executes code. This dynamic dependency allows the external source to modify the agent’s behavior without any changes to the skill itself.
Why it was flagged
At runtime the skill explicitly uses WebFetch to retrieve registry pages like https://tessl.io/registry/{workspace}/{tile}/security and https://tessl.io/registry/skills/github/{org}/{repo}/{skill-name}/security and injects those fetched findings directly into the agent's report, so remote content can control the model's output.
- Audited
- Security analysis