---
summary: 'The object model: stable handles, immutable versions, and the rigidity knob.'
title: Crew members
path: crew-members
status: published
---

# Crew members

A **crew member** is an AI worker. It is modelled as a stable handle plus a chain of immutable,
versioned definitions.

## Handle vs. version

- `crew_members` is a **stable handle** with pointer fields only (e.g. `active_version_id`).
- The actual definition — objective, instructions, tools, rules, rigidity — lives in
  `crew_member_versions`, which are **never edited after they leave `draft`**.
- Every run **pins the exact `version_id`** it executed, so history is reproducible.

Editing a published member **forks a new draft**; publishing advances `active_version_id`. This is
the immutability rule that keeps runs auditable.

## Rigidity

Rigidity is the one knob the user sees. It has four plain-language stops:

| Stop | Meaning |
|---|---|
| **Strict** | Follow the steps exactly. |
| **Guided** | Ask before any external effect (the default). |
| **Adaptive** | Work out the steps within guardrails. |
| **Autonomous** | Run end to end on its own. |

Users never see the underlying ScaiCore directives; the compiler translates the stop (combined with
each tool's effect class) into the right enforcement. Rigidity feeds directly into
[approvals](/docs/scaicrew/approvals).

> **Implemented today:** the Strict and Guided run path is complete. Adaptive/Autonomous depth is
> being rolled out — the object model and compiler already represent all four stops.

## Publishing

Publishing a draft (see the [API reference](/docs/scaicrew/api-reference)):

1. **Compiles** the version to a deterministic ScaiCore program.
2. **Stores** the compiled artifact.
3. **Provisions** the member's own ScaiKey identity on first publish.
4. **Activates** the version, with an audit-log entry.