---
title: "Agent Payments: Lobster.cash + Treeship"
description: "Lobster.cash handles wallet and settlement. Treeship proves what happened."
date: 2026-03-26
tags: ["integrations", "commerce"]
readTime: "5 min read"
---

[Lobster.cash](https://www.lobster.cash/) (by Crossmint) gives agents a payment layer: wallet provisioning, transaction signing, settlement. Treeship adds the verification layer: every transaction gets a signed receipt.

Together, they solve both halves of the agent payment problem. Lobster.cash answers "how does the agent pay?" Treeship answers "can anyone prove the agent was authorized to pay?"

## Separation of concerns

The two systems own different things:

| Layer | Owner | Responsibility |
|-------|-------|----------------|
| Wallets, signing, settlement | Lobster.cash | Move the money |
| Approval, attestation, verification | Treeship | Prove what happened |
| Intent and business logic | The agent | Decide what to do |

This separation matters. Payment infrastructure and trust infrastructure have different threat models. Combining them creates a single point of failure. Keeping them separate means each system can be audited, upgraded, and secured independently.

## The flow

### 1. Agent gets human approval

```bash
treeship attest approval \
  --approver human://ops \
  --description "approve $49.99 USDC for API credits"
```

### 2. Agent calls Lobster.cash to execute payment

The agent calls the Lobster.cash API to send USDC. This is a standard API call, nothing Treeship-specific.

### 3. Agent attests the result

Option A: Wrap the API call directly.

```bash
treeship wrap \
  --approval-nonce abc123def456 \
  -- curl -X POST https://api.lobster.cash/v1/payments \
    -H "Authorization: Bearer $LOBSTER_TOKEN" \
    -d '{"amount": "49.99", "currency": "USDC", "recipient": "0x..."}'
```

Option B: Attest the result after the fact.

```bash
treeship attest action \
  --actor agent://payments \
  --action lobster.payment.create \
  --approval-nonce abc123def456 \
  --meta '{"tx_id": "7f2a...", "amount_usdc": 49.99, "recipient": "0x..."}'
```

Both produce a signed receipt that binds the payment to the approval.

### 3b. Spend-limit proof (automatic)

When a payment is attested, Treeship runs the `spend-limit-checker` ZK circuit. This produces a zero-knowledge proof that the amount falls within the approved spend limit, without revealing the exact threshold to third-party verifiers. The proof is embedded in the receipt automatically.

### 4. The receipt chain is complete

The chain now proves:

```
human://ops approved "$49.99 USDC for API credits"
  -> agent://payments intended lobster.payment.create
    -> Lobster.cash executed tx 7f2a...
      -> receipt signed and chained
```

### 5. Anyone can verify

```bash
treeship verify --full
```

The receipt travels with the transaction. Verification happens offline, client-side. No callback to Treeship or Lobster.cash required.

## Why this pairing works

Lobster.cash solves the hard problem of agent wallets: provisioning, key management, transaction signing, settlement finality. Building this from scratch is months of work and a significant security surface.

Treeship solves the hard problem of provable authorization: who approved, what was approved, did the action match the approval. Building this from scratch is also months of work and a different security surface.

An agent using both gets wallet infrastructure and trust infrastructure without building either. The receipts from Treeship and the transaction confirmations from Lobster.cash form a complete audit trail from human intent to settled payment.

## Integration docs and Verifiable Intent

For a step-by-step setup guide, see the [Lobster Cash integration page](/docs/integrations/lobster-cash).

Lobster Cash payments are also compatible with [Verifiable Intent](/docs/integrations/verifiable-intent) credentials. When both are configured, Treeship produces the `agent_attestation` field for VI Layer 3 credentials, giving the payment a standards-compliant proof chain on top of the Treeship receipt chain.
