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REIN

On-chain spending policies
for AI agents.

The missing guardrail between autonomous agents and real money. Enforced by Anchor, auditable on Solana, live on devnet today.

Q2 2026
Hackathon built
16
Milestones shipped
Devnet
Live today
Seed
Round open
Try on devnet View roadmap

01 — The problem

AI agents are spending real money.
With zero guardrails.

The x402 protocol enables AI agents to make autonomous USDC payments on Solana. By Q2 2026, agents have processed $10M+ in volume across 35M+ transactions — with no trust checks, no caps, no audit trail.

No spending limits
A jailbroken prompt or buggy tool can drain a wallet. There is no on-chain enforcement stopping it.
No audit trail
Payments happen off-chain or in SaaS DBs. A compromised backend can alter or delete spend history.
No human override
When an agent decides to pay $2,000 to an unknown API, there is no pause-for-approval mechanism.
No multi-runtime support
Every framework (LangChain, CrewAI, Claude Code) rolls its own spend logic — no shared standard.

01b — Enterprise unlock

Public spend
is the ceiling.

A public ledger is fine for hackathons. For any business past dev-mode, every on-chain payment leaks the things that win or lose deals.

Strategic leak
Every payment reveals your stack. Competitors index your wallet and replicate your infrastructure choices in a quarter.
Customer leak
Counterparty addresses become your customer list. CRM-as-a-service for adversaries — for free, in real time.
Traction leak
Spend velocity = product traction. Investors and competitors get to read it before you publish it.
The punchline:No business will run autonomous agent commerce on a public ledger. So nobody does — yet. REIN keeps policy public and verifiable, and routes execution through Umbra's shielded UTXO pool. Solscan sees a commitment. The owner sees everything.

02 — Our solution

REIN is the trust layer
for agent commerce.

An Anchor program on Solana enforces spending rules inside every transaction — atomically. A compromised SaaS backend, a prompt injection, or a rogue dependency cannot bypass them.

Daily cap$50/day
Per-tx limit$5/tx
Step-up thresholdpause > $10
Allowlist / blocklistMerkle root
Expiry TTL90 days
Pause / dispute1-click
On-chain enforcement
Rules live in a Policy PDA — checked atomically inside every spend transaction. Not in a SaaS DB.
Immutable receipts
SpendReceipt PDA created in the same tx. Every payment is auditable, disputable, refundable on-chain.
Step-up approval
Payments above threshold pause. You approve via push notification + biometric. Agent resumes in <1s.
Drop-in for any runtime
MCP server works with Claude Code, Cursor, Claude Desktop. TypeScript + Python SDKs for LangChain, CrewAI, AutoGen.

02b — Treasury-grade insights

A wallet log
is not a ledger.

Token counts don't get sign-off. Dollar totals, week-over-week deltas, and real anomaly detection do. Every receipt is enriched with USD price at time-of-spend via GoldRush.

Today, everywhere else
Agent spent 12.5 USDC
on inference.
Token count. No USD. No reputation. No WoW. No anomalies. CFO bounces it.
REIN — live
$1,247.38 across 380 calls.
OpenAI 62% · Helius 28% · other 10%+23% WoW · 3 anomalies flaggedSame data. GoldRush-enriched.
The punchline:Sign-off goes from “I don't know what I'm approving” to “I do.” Outlier amounts (mean + 2σ), new-recipient flags, recipient reputation grading on every allowlist entry — computed live, cached at the edge.

02c — Trust model

Four keys.
Owner key never moves.

REIN keeps the owner's key off the hot path entirely. Policy is enforced on-chain. Private spend is brokered by a sidecar. Auditors see only what the owner scopes to them.

Owner key
Phantom / Backpack — never leaves the wallet
Signs policy edits, dispute, refund. Never signs the private path.
Agent key
Bound to a vault, scoped by Policy PDA
Signs public spend; on-chain rules reject everything outside the policy.
Sidecar key (Fly.io)
Isolated service · Umbra UTXO broker
Builds and signs shielded UTXO creation tx. Sees commitments — not amounts, not recipients.
View key (browser-only)
Owner-derived via signed message · never crosses the network
Decrypts confidential receipts client-side. Can be shared with auditors scope-by-scope.

03 — Product

Everything shipped. Today.

Built in one hackathon sprint. 16 milestones shipped, devnet live, real transactions confirmed.

On-chain program
7 Anchor instructions
Policy PDA + Receipt PDA
Daily cap, per-tx, step-up, allowlist, expiry, pause, dispute
MCP server
rein_spend · rein_balance · rein_history · request_step_up
Works in Claude Code, Cursor, Claude Desktop out of the box
rein init CLI — installs MCP config in any runtime
SDKs
TypeScript SDK — LangChain tool wrappers, Vercel AI SDK helpers, OpenAI Functions JSON schema
Python SDK — CrewAI / LangGraph / AutoGen compatible
pip install rein · npm install @rein/sdk
Dashboard
Policy editor, activity feed, step-up UI, spend insights
Real-time WebSocket receipts via Helius webhook
Cloudflare Workers + Durable Objects activity stream

04 — Traction

The agentic economy
is already here.

x402 volume is real. REIN ships into a live ecosystem with immediate distribution through the Solana ecosystem, MCP tooling, and AI developer communities.

$10M+
x402 volume on Solana devnet
35M+
Agent transactions confirmed
16
Milestones shipped (Q2 2026)
<2s
End-to-end spend latency
MCP ecosystem
Claude Code has 500k+ developers. REIN's MCP server drops in with a single rein init — zero configuration.
Python SDK
CrewAI, LangGraph, AutoGen combined have millions of monthly downloads. pip install rein is the distribution.
Solana Foundation
Eligible for Q3 2026 RFP grant for security audit funding. Squads multisig partnership for mainnet upgrade authority.
Hackathon credibility
Built and shipped in one sprint with real on-chain program, MCP integration, and a live dashboard. Not a demo.

05 — Market

Every autonomous agent
is a potential customer.

AI agent commerce is nascent but accelerating fast. REIN targets the infrastructure layer — not applications — which means it rides every vertical simultaneously.

TAM
$18B
AI agent infrastructure spend by 2028 (a16z est.)
SAM
$2.4B
Solana + MCP-compatible agent deployments
SOM (Y1)
$12M
Policy vaults × $15/mo avg. in first 12 months
Why now: Visa's Trusted Agent Protocol, Stripe's Agent Commerce Protocol, and Anthropic's MCP standard all launched in 2025—2026. The x402 payment standard has proven demand. The missing piece is the policy and trust layer. REIN is that piece.

06 — Business model

Simple pricing.
Usage-aligned revenue.

Free
$0forever
1 vault
Basic policy (cap + expiry)
On-chain receipts
MCP server access
Pro
$29/ month
Unlimited vaults
All 7 policy controls
Step-up push notifications
Spend insights + anomaly flags
CSV / JSON export
Priority support
Enterprise
Customannual
SSO + SLA
Custom domains
Audit log export
Key broker (rein.proxy)
Squads multisig integration
Dedicated support
Revenue stream 2
Usage fees
0.1% on proxied API spend via rein.proxy — agents never see the key, REIN earns on every call.
Revenue stream 3
Agent marketplace
Policy templates sold peer-to-peer. 20% platform cut on each sale. Planned Q4 2026.

07 — Roadmap

Mainnet in Q3.
Enterprise in Q4.

Q2 2026 — Done
Anchor program — 7 instructions, Policy + Receipt PDAs
MCP server + TypeScript + Python SDKs
Owner dashboard — policy editor, activity, step-up, insights
Q3 2026
External security audit (Solana Foundation RFP)
Mainnet launch — Squads multisig upgrade authority
Immunefi bug bounty + key broker (2-of-3 Shamir)
Q4 2026
Enterprise tier — SSO, SLA, audit export
Mobile app — push approvals on iOS + Android
Agent marketplace — sell policy templates
2027
Multi-chain — EVM (Base, Arbitrum) + Cosmos IBC
KYA — Know Your Agent on-chain identity attestations
Visa + Stripe bridge — x402 on fiat rails

08 — Defensibility

Why REIN wins
the infrastructure race.

On-chain moat
Policy PDAs and Receipt PDAs cannot be censored, altered, or deleted. An equivalent SaaS product is always one database breach away from failure. REIN's on-chain model is the only trustworthy option for regulated deployments.
MCP standard lock-in
The rein init CLI installs REIN's MCP config into Claude Code, Cursor, and Claude Desktop in seconds. Being the first policy tool in the MCP ecosystem creates switching-cost network effects for every agent developer who adopts it.
Protocol-level reach
rein.proxy ships in Q3 2026. Once agents route API keys through REIN's proxy, we earn on every OpenAI, AWS, and GitHub call — not just Solana payments. This is a cross-chain, cross-runtime trust layer.
Timing advantage
Visa TAP, Stripe ACP, and Anthropic MCP all launched in 2025–2026. The window for the canonical trust-layer standard is open now. The team that ships mainnet in Q3 2026 owns the ecosystem.
Competitive landscape: No direct competitor combines on-chain enforcement + MCP tooling + key brokering. Existing solutions (SaaS rate limiters, wallet guards) operate in a different trust model — they can be bypassed. REIN cannot.

09 — The ask

$1.5M seed round.

Targeting close by end of Q3 2026 — aligned with mainnet launch and audit completion.

40%
Security audit + Immunefi bounty
30%
Engineering — key broker, mobile app
20%
Growth + developer relations
10%
Legal + compliance (KYA framework)
Contact the team Try on devnet
ProductRoadmapDocsGitHub

REIN © 2026 · Built on Solana · Devnet live