Personality Variant Overlay

Problem

Forcing every register into one neutral voice flattens the agent and makes some moves impossible (a teacherly explanation in the same flat tone as a deadpan technical note). Spinning up separate personas as different agents preserves register but breaks continuity — each persona has its own short memory, and the user is now talking to a stranger when the register shifts. A jailbreak-style 'now act as X' overlay loses identity entirely because the base personality is overwritten rather than overlaid. None of these match the situation where the agent should still be itself, but speaking in a particular voice.

Solution

Maintain a small registry of named variants (e.g. 'teacher', 'operator', 'caring-coach', 'archivist'). Each variant is a short overlay block — a few sentences describing tone, pacing, vocabulary — that is concatenated onto the base system prompt at turn time, never replacing it. The agent (or an upstream selector) chooses a variant per turn. The chosen variant is visible in telemetry and may be visible to the user. Memory, tools, charter, and name are shared across all variants. Variant overlays must not contradict the base charter: the registry is curated, not user-supplied.

When to use

• The agent has an explicit base personality the team wants to preserve.
• Different situations call for different registers without losing continuity.
• Selection is from a finite, curated set rather than free-form impersonation.