Agent Skills Layer
Agent Skills Layer
NEW IN 2026
Skills are an emerging complement to MCP tools: composed, reusable capability bundles (instructions + optional scripts/resources) that an agent loads on demand, rather than a live tool connection. The MCP roadmap lists a formal Skills primitive as an active 2026 work item, alongside the existing ext-auth and ext-apps extension tracks.
Practical distinction for architecture decisions:
● MCP tools — for live, stateful, or side-effecting connections to external systems (databases, APIs, SaaS products).
● Skills — for packaged, mostly-static know-how (a house style guide, a document-formatting procedure, a domain checklist) that doesn't need a network connection to a server.
● Both should be routed through the same permissioning and audit layer as everything else in the harness — a Skill is still executable content and should be treated as untrusted input until vetted.
Safety Classification for Tools
Levels |
Skills |
Controls |
|
Low |
Informational |
Auto execute + log |
|
Medium |
Controlled side effects |
Policy checks + confidence threshold |
|
High |
Financial / irreversible / legal |
Verifier + human approval |
Mandatory Rules
High-risk actions require:
● Human approval
● Full audit trail
● Secondary verification
● Explicit user identity