How do I install the Skillsign skill?

Run npx skillmds@latest add kbarbel640-del/skillsign in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Skillsign safe to use?

This skill has not completed SkillMD's automated safety review yet. Independent scanners report: SkillSpector: PASS, Skill Scanner: PASS. Capability flags: executes scripts, reads secrets. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Skillsign?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Skillsign free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Skillsign?

kbarbel640-del (@kbarbel640-del) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Skillsign by kbarbel640-del — Agent Skill

Name: Skillsign
Rating: 4.2 (5 reviews)
Author: kbarbel640-del

File contents

skillsign

Cryptographic signing and verification for agent skill folders using ed25519 keys. Protects your skills from tampering and lets you verify who wrote them.

Install

pip3 install cryptography

That's the only dependency. The tool is a single Python file.

Commands

Generate a signing identity

python3 skillsign.py keygen
python3 skillsign.py keygen --name myagent

Creates an ed25519 keypair in ~/.skillsign/keys/. Share the .pub file. Keep the .pem file secret.

Sign a skill folder

python3 skillsign.py sign ./my-skill/
python3 skillsign.py sign ./my-skill/ --key ~/.skillsign/keys/myagent.pem

Hashes every file (SHA-256), builds a manifest, signs it with your private key. Creates .skillsig/ inside the folder.

Verify a skill folder

python3 skillsign.py verify ./my-skill/

Detects modified, added, or removed files. Verifies the cryptographic signature. Shows whether the signer is trusted.

Inspect signature metadata

python3 skillsign.py inspect ./my-skill/

Shows signer fingerprint, timestamp, file count, and all covered files with their hashes.

Trust an author

python3 skillsign.py trust ./their-key.pub

Adds a public key to your local trusted authors list.

List trusted authors

python3 skillsign.py trusted

View provenance chain (isnād)

python3 skillsign.py chain ./my-skill/

Shows the full signing history — every author who signed the folder, in order.

When to Use

After installing a new skill — verify it hasn't been tampered with
Before running untrusted code — check who signed it and whether you trust them
Periodically — re-verify your skill folders to detect unauthorized modifications
When publishing skills — sign your work so others can verify it came from you
When auditing your agent's integrity — run verify on all your skill folders

Example Workflow

# First time: create your identity
python3 skillsign.py keygen --name parker

# Sign your skills
python3 skillsign.py sign ~/.openclaw/skills/my-skill/

# Later: check nothing changed
python3 skillsign.py verify ~/.openclaw/skills/my-skill/
# ✅ Verified — 14 files intact.
#    Signer: ca3458e92b73e432 [TRUSTED]

# Someone tampers with a file:
python3 skillsign.py verify ~/.openclaw/skills/my-skill/
# ❌ TAMPERED — Files changed since signing:
#    ~ main.py (modified)

# Trust another agent's key
python3 skillsign.py trust ./other-agent.pub

# View full provenance
python3 skillsign.py chain ~/.openclaw/skills/my-skill/
# === Isnād: my-skill/ (2 links) ===
#   [1] ca3458e92b73e432 [TRUSTED]
#       ↓
#   [2] f69159d8a25e8e32 [UNTRUSTED]

---name: skillsigndescription: Sign and verify agent skill folders with ed25519 keys. Detect tampering, manage trusted authors, and track provenance chains (isnād).---# skillsignCryptographic signing and verification for agent skill folders using ed25519 keys. Protects your skills from tampering and lets you verify who wrote them.## Install```bashpip3 install cryptography```That's the only dependency. The tool is a single Python file.## Commands### Generate a signing identity```bashpython3 skillsign.py keygenpython3 skillsign.py keygen --name myagent```Creates an ed25519 keypair in `~/.skillsign/keys/`. Share the `.pub` file. Keep the `.pem` file secret.### Sign a skill folder```bashpython3 skillsign.py sign ./my-skill/python3 skillsign.py sign ./my-skill/ --key ~/.skillsign/keys/myagent.pem```Hashes every file (SHA-256), builds a manifest, signs it with your private key. Creates `.skillsig/` inside the folder.### Verify a skill folder```bashpython3 skillsign.py verify ./my-skill/```Detects modified, added, or removed files. Verifies the cryptographic signature. Shows whether the signer is trusted.### Inspect signature metadata```bashpython3 skillsign.py inspect ./my-skill/```Shows signer fingerprint, timestamp, file count, and all covered files with their hashes.### Trust an author```bashpython3 skillsign.py trust ./their-key.pub```Adds a public key to your local trusted authors list.### List trusted authors```bashpython3 skillsign.py trusted```### View provenance chain (isnād)```bashpython3 skillsign.py chain ./my-skill/```Shows the full signing history — every author who signed the folder, in order.## When to Use- **After installing a new skill** — verify it hasn't been tampered with- **Before running untrusted code** — check who signed it and whether you trust them- **Periodically** — re-verify your skill folders to detect unauthorized modifications- **When publishing skills** — sign your work so others can verify it came from you- **When auditing your agent's integrity** — run verify on all your skill folders## Example Workflow```bash# First time: create your identitypython3 skillsign.py keygen --name parker# Sign your skillspython3 skillsign.py sign ~/.openclaw/skills/my-skill/# Later: check nothing changedpython3 skillsign.py verify ~/.openclaw/skills/my-skill/# ✅ Verified — 14 files intact.# Signer: ca3458e92b73e432 [TRUSTED]# Someone tampers with a file:python3 skillsign.py verify ~/.openclaw/skills/my-skill/# ❌ TAMPERED — Files changed since signing:# ~ main.py (modified)# Trust another agent's keypython3 skillsign.py trust ./other-agent.pub# View full provenancepython3 skillsign.py chain ~/.openclaw/skills/my-skill/# === Isnād: my-skill/ (2 links) ===# [1] ca3458e92b73e432 [TRUSTED]# ↓# [2] f69159d8a25e8e32 [UNTRUSTED]```

Frequently asked questions

Skillsign