Add agentskill-learn: Community skills marketplace

docs/README.skills.md

@@ -29,6 +29,7 @@ See [CONTRIBUTING.md](../CONTRIBUTING.md#adding-skills) for guidelines on how to
 | [add-educational-comments](../skills/add-educational-comments/SKILL.md) | Add educational comments to the file specified, or prompt asking for file to comment if one is not provided. | None |
 | [agent-governance](../skills/agent-governance/SKILL.md) | Patterns and techniques for adding governance, safety, and trust controls to AI agent systems. Use this skill when:<br />- Building AI agents that call external tools (APIs, databases, file systems)<br />- Implementing policy-based access controls for agent tool usage<br />- Adding semantic intent classification to detect dangerous prompts<br />- Creating trust scoring systems for multi-agent workflows<br />- Building audit trails for agent actions and decisions<br />- Enforcing rate limits, content filters, or tool restrictions on agents<br />- Working with any agent framework (PydanticAI, CrewAI, OpenAI Agents, LangChain, AutoGen) | None |
 | [agentic-eval](../skills/agentic-eval/SKILL.md) | Patterns and techniques for evaluating and improving AI agent outputs. Use this skill when:<br />- Implementing self-critique and reflection loops<br />- Building evaluator-optimizer pipelines for quality-critical generation<br />- Creating test-driven code refinement workflows<br />- Designing rubric-based or LLM-as-judge evaluation systems<br />- Adding iterative improvement to agent outputs (code, reports, analysis)<br />- Measuring and improving agent response quality | None |
+| [agentskill-learn](../skills/agentskill-learn/SKILL.md) | Discover, install, and manage AI agent skills from agentskill.sh marketplace. Search 44,000+ community skills by keyword, install mid-session with security scanning, and rate skills after use. Use when asked to find skills, extend capabilities, or learn new tools. | None |
 | [ai-prompt-engineering-safety-review](../skills/ai-prompt-engineering-safety-review/SKILL.md) | Comprehensive AI prompt engineering safety review and improvement prompt. Analyzes prompts for safety, bias, security vulnerabilities, and effectiveness while providing detailed improvement recommendations with extensive frameworks, testing methodologies, and educational content. | None |
 | [appinsights-instrumentation](../skills/appinsights-instrumentation/SKILL.md) | Instrument a webapp to send useful telemetry data to Azure App Insights | `LICENSE.txt`<br />`examples/appinsights.bicep`<br />`references/ASPNETCORE.md`<br />`references/AUTO.md`<br />`references/NODEJS.md`<br />`references/PYTHON.md`<br />`scripts/appinsights.ps1` |
 | [apple-appstore-reviewer](../skills/apple-appstore-reviewer/SKILL.md) | Serves as a reviewer of the codebase with instructions on looking for Apple App Store optimizations or rejection reasons. | None |

skills/agentskill-learn/SKILL.md

@@ -0,0 +1,54 @@
+---
+name: agentskill-learn
+description: "Discover, install, and manage AI agent skills from agentskill.sh marketplace. Search 44,000+ community skills by keyword, install mid-session with security scanning, and rate skills after use. Use when asked to find skills, extend capabilities, or learn new tools."
+---
+
+# AgentSkill Learn — Community Skills Marketplace
+
+This skill connects GitHub Copilot to [agentskill.sh](https://agentskill.sh), a community marketplace for AI agent skills. Search, install, and manage skills with built-in security scanning.
+
+## Installation
+
+This is a pointer to the canonical skill. Install the full version:
+
+```bash
+gh copilot skill install https://github.com/agentskill-sh/learn
+```
+
+## What It Does
+
+- **Search**: Find skills by keyword from the agentskill.sh catalog (44,000+ skills indexed)
+- **Install**: Download skills with security scanning (blocks dangerous patterns)
+- **Rate**: Auto-rate skills after use; user ratings override
+- **Update**: SHA-based version tracking for updates
+- **Multi-platform**: Works with Copilot, Claude Code, Codex, Cursor, Windsurf, Cline
+
+## Quick Commands
+
+| Command | Description |
+|---------|-------------|
+| `/learn <query>` | Search for skills |
+| `/learn @owner/slug` | Install specific skill |
+| `/learn trending` | Show trending skills |
+| `/learn list` | Show installed skills |
+| `/learn update` | Check for updates |
+| `/learn scan <path>` | Security scan a skill |
+
+## Security
+
+**Two-layer security model:**
+
+1. **Registry-side**: All skills pre-scanned at publish time with pattern detection (command injection, data exfiltration, prompt injection, credential harvesting, obfuscation)
+2. **Client-side**: Score displayed before install; skills below 70 blocked, 70-89 require acknowledgment
+
+| Score | Action |
+|-------|--------|
+| 90-100 | SAFE — install proceeds |
+| 70-89 | REVIEW — requires acknowledgment |
+| <70 | BLOCKED — installation refused |
+
+## Links
+
+- **Marketplace**: https://agentskill.sh
+- **Source**: https://github.com/agentskill-sh/learn
+- **Report Issues**: https://github.com/agentskill-sh/learn/issues