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Open standard · Character infrastructure

Protagons

Portable character identity for any AI model.

Role
Creator of the standard
Type
Open standard + API
Timeline
2025
Live at
protagons.com
Protagons homepage introducing its open AI character identity standard

Part of a system

Open Protagons is the schema underneath USAW, extracted and published so a character isn’t trapped in the product that captured it. Add the behavioural layer and the same file drives the AI buyers in Sales Practice.

The friction

AI personas live as prose system prompts. You can’t diff them, fork them, or move them between models without hand-rewriting — and the reasoning walks out the door when the prompt engineer does. Two products that need one voice means copy-paste-and-pray. Prose has no source of truth.

Where AI helps

Protagons started as USAW’s internal schema. Opening it meant wrapping the analysis in something anyone could write against: the same 28 dimensions, verbatim, plus the envelope that makes a character portable — identity, provenance, safety tiers, TTS config, deployment targets, and an extension point. A pipeline of 28 agents fills all 287 fields from a description or real writing samples in about two minutes, evidence-backed and confidence-scored. Compile the result to any model and the character holds.

Who it helps — Developers and builders wiring characters into products — agents, NPCs, brand-voice systems, TTS pipelines. USAW is the end-user product this schema was extracted from; Sales Practice is what it does once you extend it.

What I built

  • An open schema

    JSON Schema 2020-12. The 28 linguistic and psychological dimensions sit under one dimensions key, wrapped in everything portability needs — provenance, safety tiers, deployment targets, TTS config.

  • An extension point

    The Behavioural Agency Layer adds ten dimensions for how a character acts under pressure — stress response, trust dynamics, conflict, adaptation — by appending a top-level key that modifies nothing already in the file. A character gains capability without a rewrite, and anyone can publish a layer of their own.

  • A compiler

    One .protagon.json becomes a system prompt, SOUL.md, ElevenLabs voice, or Custom GPT; recompile per model.

Proof

28 dimensionsExtends without rewritingJSON Schema 2020-12800+ public profilesFree BYOK API