Summary · Hands

Key takeaways

  • Hands complete the Pico progression that Part 3 has been building: Identity → Senses → Mind → Voice → Hands. Hands are the boundary between understanding and changing the world.
  • Mind decides should I do this?; Hands determine how do I do this?.
  • Hands are provider-neutral: the Pico depends on capabilities (email.send, github.issue.create), not provider tool names (GMAIL_SEND_EMAIL). Composio is one provider among many, and is optional and non-runnable in this wave.
  • Identity before action: no Hand acts without identity and authorization context. A valid credential does not imply authorization.
  • A Hand invocation crosses seven distinct concerns — Composer equipment, Pico decision, Policy authorization, Hand selection, Provider execution, Evidence, and Action event — and each is owned by a different actor. Collapsing any two weakens the architecture.
  • Evidence and action events are separate: evidence is what happened, kept in Pico memory; the action event is what the Pico’s Voice broadcasts so others can react.
  • Hands ≠ MCP. Hands are the Pico capability abstraction; MCP is one integration mechanism; Composio is one provider/platform.

The governing principle

The Composer equips.
The Pico decides.
The Policy authorizes.
A Hand is selected.
The Provider executes.
Evidence is recorded.
The Voice publishes the event.
Open Engineering governs the whole loop.

What comes next

  • Return to the Part 3 overview to review all lessons, or revisit any lesson in this course: Course home.
  • Optional, non-runnable extension: Composio as a Hands provider — shows how a provider-neutral capability maps behind ComposioHands without changing Pico rules, and where Composio authentication stops and Open Engineering authorization begins.

Next

Take the Quiz to finish the lesson.