# PXP — Proxy Exchange Protocol

> PXP (Proxy Exchange Protocol) is an open, transport-agnostic protocol for AI agents that negotiate on behalf of humans: every claim is tagged stated, sourced or assumed, proxies escalate to their principals at a limit, and an agreement produces a decision brief and a hash-chained ledger.

PXP is a draft (v0); expect breaking changes until v1. It specifies the content proxies exchange
(Intent Cards, envelopes, claims with origin tags, reviews, escalation, a hash-chained ledger and a
decision brief), and an optional MCP transport binding. The reference implementation is Behalf.

## Specification

- [PXP v0 specification (Markdown)](https://julesnsenda.github.io/pxp/v0/SPEC.md): the normative protocol
- [Intent Card JSON Schema](https://julesnsenda.github.io/pxp/v0/intent-card.schema.json): what a principal authorises its proxy to do
- [Envelope JSON Schema](https://julesnsenda.github.io/pxp/v0/envelope.schema.json): one proxy message: claims, reviews, proposal, status

## Implementations

- [Behalf](https://github.com/JulesNsenda/behalf): reference implementation; two AI proxies negotiate for two humans, with a remote MCP server so any MCP-capable agent can take a seat

## Optional

- [Full text for LLMs](https://julesnsenda.github.io/pxp/llms-full.txt): the specification and both schemas in one file
- [Source repository](https://github.com/JulesNsenda/pxp): issues and proposed changes