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promptsign

v0.3.4

Verifies signatures on the instruction files Claude Code loads, meaning CLAUDE.md, skills, and agent definitions, before they reach model context. It re-checks a skill bundle before the Skill tool runs it. Sigstore keyless, offline verification against a pinned trust root, no telemetry.

Claude Code2 Skills

By Sergey VasilevskiyLicense: Apache-2.00 GitHub starsUpdated 2 weeks ago

Directory evidence

Runtimes
Claude Code
Parsed components
2 skill or MCP entries
Source updated
Sep 4, 2026
Manifest status
Canonical path parsed

The directory validates manifest shape and source location. It does not execute the plugin or provide a security endorsement. Review the indexing methodology →

Install promptsign for Claude Code

Installs for the current user
claude plugin marketplace add IchenDEV/agent-plugin-mkt
claude plugin marketplace update agent-plugin-marketplace
claude plugin install promptsign@agent-plugin-marketplace

Paste and run these commands in a terminal with Claude Code. They add and refresh the PluginsMP catalog, then install this plugin.

The installer fetches third-party code from the source repository shown on this page. This directory validates manifest structure and source location, but does not perform a security audit; review the manifest, components, and source before installing.

Get the source manually
git clone https://github.com/PromptSign/promptsign-plugin

Clone the source repository, then follow its setup instructions to add the plugin to a compatible client. The repository root is the plugin root.

Plugin files

promptsign/
├── .claude-plugin/plugin.json
├── skills/setup/SKILL.md
└── skills/verify/SKILL.md

Included Skills2

setupskills/setup/SKILL.md

Check or repair the PromptSign plugin's verifier, reporting which verifier is active, which trust root is in use, and whether anything is actually being verified. Use when PromptSign reports it has no verifier, after installing the plugin, or when the user asks why signatures are not being checked.

verifyskills/verify/SKILL.md

Verify PromptSign signatures on a skill, plugin, agent definition, CLAUDE.md, or a whole directory tree, and explain the result. Use when the user asks whether a file or skill is signed, who signed it, or whether a downloaded skill can be trusted.

Plugin manifests1

.claude-plugin/plugin.json
{
  "name": "promptsign",
  "version": "0.3.4",
  "description": "Verifies signatures on the instruction files Claude Code loads, meaning CLAUDE.md, skills, and agent definitions, before they reach model context. It re-checks a skill bundle before the Skill tool runs it. Sigstore keyless, offline verification against a pinned trust root, no telemetry.",
  "author": {
    "name": "Sergey Vasilevskiy",
    "email": "[email protected]",
    "url": "https://promptsign.ai"
  },
  "homepage": "https://promptsign.ai/integrate?c=plugin-listing",
  "repository": "https://github.com/PromptSign/promptsign-plugin",
  "license": "Apache-2.0",
  "keywords": [
    "security",
    "supply-chain",
    "sigstore",
    "signing",
    "verification"
  ]
}

For maintainers

If you maintain this plugin, link to this source-backed listing from your README so users can review its manifest and indexed components.

[promptsign on Agent Plugins Marketplace](https://pluginsmp.com/plugins/promptsign)