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MPCP Ecosystem Roadmap

MPCP development is tracked per-repository. Implementation status for each component is summarised below.

Repositories

Repository Role Status
mpcp-reference Protocol core — canonical SDK, verifier, schemas, anchoring adapters, golden vectors Complete (Phase 1–6)
mpcp-policy-authority Deployable policy authority service — grant issuance, revocation, Trust Bundle issuance, on-chain anchoring Complete
mpcp-wallet-sdk Wallet SDK — session management, SBA signing, budget enforcement (Node.js + browser) Archived — superseded by mpcp-gateway-client
mpcp-merchant-sdk Merchant SDK — SBA verification, revocation caching, spend tracking, framework adapters (Express / Fastify / Next.js / Edge) Archived — gateway enforcement + mpcp-service
mpcp-gateway Transparent payment gateway — speaks x402 externally, enforces MPCP internally; bridges non-MPCP agents to MPCP merchants Complete (P1–P10)
mpcp-gateway-client Agent-side fetch wrapper — GatewayClient + session.fetch(); receipts; Trust Bundle; React hooks; framework adapters Complete (P1–P6)
mpcp-spec Protocol specification, architecture docs, guides this site

Implementation status

mpcp-reference

All phases (1–6) complete.

Implemented: canonical serialization · artifact schemas · full verification engine · CLI verifier with explain mode · Hedera HCS and XRPL anchor adapters · did:xrpl resolver · XRPL Credential-based grant liveness (spec); legacy NFT path deprecated · Trust Bundle signing and verification · resolveFromTrustBundle for key lookup · AES-256-GCM encrypted policy anchoring · golden protocol vectors · human-to-agent delegation profile · TRIP budget scope · checkRevocation utility · XRPL stablecoin profile (RLUSD) · Layer-1 ecosystem evaluation · machine wallet guardrails documentation · fleet payment demos · MPCP conformance badge (L0–L3 tiers).

mpcp-policy-authority

All phases complete. Grant issuance, policy custody, revocation (HTTP and/or XRPL Credentials per deployment), Trust Bundle issuance and signing, persistent custody with soft-delete, audit log with webhook dispatch, multi-key admin API.

mpcp-wallet-sdk

All core and ecosystem integration phases complete. Node.js monorepo (@mpcp/core, @mpcp/agent, @mpcp/issuer, @mpcp/react).

Implemented: parseGrant · createSession(grant, opts) → Session · session.createSba({ amount, currency, rail }) · per-session budget ceiling enforcement · live revocation checking with TTL cache · session.remaining() · SQLite session persistence via Drizzle · Web Crypto signing path (CryptoKey support for browser) · @mpcp/react package (usePolicyGrant, useSession hooks) · createX402Client adapter (MPCP budget enforcement wrapping x402-gated APIs) · full integration test suite.

Deferred: React Native bundle + AsyncStorage adapter (PR7).

mpcp-merchant-sdk

All phases complete. Full Express / Fastify / Next.js / Edge (Web Crypto) adapter suite.

Implemented: verifyMpcp(sba, opts) · mpcp() Express/Fastify middleware · withMpcp() Next.js HOC · verifyMpcpEdge (zero Node.js deps) · Trust Bundle key resolution (trustBundles option) · revocation checking with TTL cache · spend tracking · verifyMpcpEdge Ed25519 + P-256 support.

mpcp-gateway

All phases (P1–P10) complete. The gateway bridges non-MPCP agents to MPCP merchants: intercepts HTTP 402, executes x402 payments, enforces session budgets/purposes/policies, and optionally attaches a signed SBA (X-Mpcp-Sba) so MPCP-aware merchants can verify the authorization chain.

Implemented:

  • P1 — Core proxy + x402 interception
  • P2 — Session CRUD REST API (POST / GET / DELETE /sessions)
  • P3 — Ed25519-signed receipts + audit log (GET /sessions/:id/receipts)
  • P4 — MPCP passthrough headers (X-Mpcp-Sba on 402 retry)
  • P5 — Production hardening: health/ready/metrics endpoints; pluggable PaymentRail; KeyRing with rotation; Dockerfile; SQLite session persistence (Drizzle + better-sqlite3 WAL)
  • P6 — Trust Bundle auto-distribution (/.well-known/mpcp-trust-bundle.json; zero merchant env-var config)
  • P7 — Spend webhooks: HMAC-signed push notifications at configurable thresholds; payment.denied events; dispatch log
  • P8 — Session policy controls: merchant allowlist/blocklist (glob); velocity limits (max payments/hour, max amount per merchant/day)
  • P9 — Soft budget ceiling + continuation token: budget exhaustion pauses instead of hard-failing; PATCH /sessions/:id raises ceiling via single-use HMAC token
  • P10 — x402 merchant mode: POST /charge / GET /charge/:id/verify; /.well-known/x402-payment-info

Deferred items (each a standalone PR): PostgreSQL adapter, Redis session cache, per-owner rate limiting, OpenTelemetry traces, Prometheus text-format metrics.

mpcp-gateway-client

P1–P6 complete.

Implemented:

  • P1 — Core client: GatewayClient, createSession, session.fetch() wrapper, session CRUD; zero runtime deps; TypeScript + ESM
  • P2 — Soft-limit continuation: onSoftLimit callback; continueSession(); automatic retry on user approval
  • P3 — Framework adapters: GatewayFetchTool (LangChain), gatewayFetchTool() (Vercel AI SDK), gatewayFetchFn() (generic function-calling / AutoGen)
  • P3b — React hooks: usePolicyGrant, useGatewaySession (mpcp-gateway-client/react)
  • P4 — Receipts + audit: getReceipts(), verifyReceipt() (Ed25519), fetchGatewayKeys(); mpcp-gateway-client/receipts entry point
  • P5 — Ecosystem consolidation: mpcp-wallet-sdk and mpcp-merchant-sdk superseded; migration docs; archive notices
  • P6 — Trust Bundle: fetchGatewayTrustBundle(), typed TrustBundle; aligns with mpcp-gateway P6

Spec roadmap

Spec changes accompany each reference implementation PR that introduces new protocol fields or behaviors.

Upcoming spec work:

  • mpcp-wallet-sdk PR7 (React Native bundle) — spec alignment when implemented (low priority; repo archived)