> For the complete documentation index, see [llms.txt](https://handbook.harmonic.security/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://handbook.harmonic.security/handbook/2.-supply-chain-and-extensibility.md).

# 2. Supply Chain & Extensibility

How to govern connectors, MCP servers, plugins, skills, extensions, hooks, and agent frameworks as a software supply chain with real attack surface.

*Last reviewed: August 18, 2026*

{% hint style="info" %}
Every connector, MCP server, plugin, skill, and hook is a software dependency with real attack surface. Treat the AI extension ecosystem the same way you treat third-party code — with intake, review, allowlisting, and owner accountability.
{% endhint %}

## Articles in this section

1. [2.1 Connectors and apps: the integration backbone](/handbook/2.-supply-chain-and-extensibility/2.1-connectors-and-apps-the-integration-backbone.md)
2. [2.2 MCP servers: securing the protocol](/handbook/2.-supply-chain-and-extensibility/2.2-mcp-servers-securing-the-protocol.md)
3. [2.3 MCP gateways and allowlisting](/handbook/2.-supply-chain-and-extensibility/2.3-mcp-gateways-and-allowlisting.md)
4. [2.4 Analyzing skills for risk](/handbook/2.-supply-chain-and-extensibility/2.4-analyzing-skills-for-risk.md)
5. [2.5 Plugins and marketplaces](/handbook/2.-supply-chain-and-extensibility/2.5-plugins-and-marketplaces.md)
6. [2.6 AI hooks: inference controls and lifecycle automation](/handbook/2.-supply-chain-and-extensibility/2.6-ai-hooks-inference-controls-and-lifecycle-automation.md)
7. [2.7 The supply-chain review workflow](/handbook/2.-supply-chain-and-extensibility/2.7-the-supply-chain-review-workflow.md)
8. [2.8 Signing and packaging](/handbook/2.-supply-chain-and-extensibility/2.8-signing-and-packaging.md)
9. [2.9 SaaS agent-building supply-chain](/handbook/2.-supply-chain-and-extensibility/2.9-saas-agent-building-supply-chain.md)
10. [2.10 Hosted-agent framework dependencies](/handbook/2.-supply-chain-and-extensibility/2.10-hosted-agent-framework-dependencies.md)

## Frequently asked questions

**What belongs in the AI supply-chain register?**\
Record every connector, MCP server, skill, plugin, hook, model, SDK, container, template, and agent framework with its owner, source, version, permissions, data reach, review date, and update trigger. Include components supplied through marketplaces and repositories.

**When must an extension be reviewed again?**\
Review after a material permission, owner, source, version, signing, tool, dependency, or update-channel change. Re-run the review after incidents and when a component begins handling a new data class or production action.

## Related handbook guidance

* [AI Security Handbook](/ai-security-handbook.md)
* [5.3 Supply chain attacks and notable CVEs](/handbook/5.-threats-and-adversarial/5.3-supply-chain-attacks-and-notable-cves.md)
* [7.4 The vendor-neutral control matrix](/handbook/7.-rollout-and-operations/7.4-the-vendor-neutral-control-matrix.md)
* [Security Team Checklist](/start-here/security-team-checklist.md)


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