// outline - full essay drafting; takeaways and bridge below
A generic assistant cannot represent a specific engineer’s expertise, owned systems, style, permissions, attention budget, escalation thresholds, or risk boundaries.
This piece defines the developer digital twin as a declarative runtime profile: identity, role, working agreements, expertise, owned systems, preferred tools, routing defaults, delegation rules, communication style, and escalation boundaries.
CTO: A twin should encode how an engineer delegates, not just how they code.
CIO: Twins give governance concrete artifacts to inspect: permissions, routing, escalation, and evidence.
AI leader: Do not build a generic “AI developer.” Build role-bound operating surfaces.
Once every engineer has a delegation contract, work can cross the boundary between day and night.