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PPX — Preference Profile Exchange

Portable, user-owned, consented preference and context profiles for agent ecosystems.

Status: Draft v0.1.0

PPX is an early-stage specification published for community review. Expect breaking changes before 1.0. See versioning policy.

See it work

PPX isn't only a document. A live, conformance-passing provider runs at ppx.dev/ppx, and four applications read a real profile through its consent flow — each seeing only the slice you approve, and every grant revocable. The same profile is reachable over the protocols agents already speak.

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The positioning

MCP standardizes tool and data access. A2A standardizes agent collaboration. AG-UI standardizes live app interaction. PPX standardizes the missing layer: portable, user-owned preference and context profiles that agents can request, explain, and use with permission.

Layer Standard
Tool / data access MCP
Agent-to-agent collaboration A2A
Live agent ↔ app AG-UI
Generated declarative UI A2UI
User preference / context PPX

Why PPX

Today, agents and apps personalize poorly because user context is fragmented, static, locked into individual products, and often hidden from the user. Apps repeatedly ask the same questions, infer things opaquely, and cannot safely share user-approved context across domains.

PPX defines a small, extensible core for:

  • Portability — profiles can move across applications and agents.
  • User ownership — the user can inspect, export, correct, revoke.
  • Scoping — access is limited by domain, purpose, allowed keys, operations, and time.
  • Explainability — every non-trivial claim has provenance and confidence.
  • Extensibility — domains can define vocabularies without destabilizing the core.

What you can do with it

  • A fragrance app asks for scent and sensory preferences, with a 30-day scoped grant.
  • A travel app asks for climate and pace preferences, optionally reusing transferable core traits under user review.
  • A dating agent receives a derived compatibility view, never the raw profile.
  • A finance app (higher-risk, out of scope for v0.1) would require stricter policy than v0.1 defines.

The user always sees what was asked for, why, how long access lasts, whether the app can write back changes, and what was inferred vs stated.

Start here

Status

PPX v0.1.0 is a draft proposal. Breaking changes are expected before 1.0. The reference implementation — ppx-provider — is under construction and proves the spec end-to-end, including the canonical fragrance → travel cross-domain consent-transfer demo.

License