# Cartesio by Sequence

> Financial infrastructure for AI agents. Cartesio lets agents read balances, trigger rules, and move money — with guardrails only you define.

## What Cartesio Is

Cartesio is a programmable financial execution layer built for AI agents. Humans configure financial rules once in the Sequence console; agents execute those rules via a REST API or MCP server. Agents never have free-form access to funds — every action is bounded by rules, transfer caps, and scoped API tokens.

Cartesio is currently in closed beta. Access is opening in batches via waitlist at https://cartesio.getsequence.io.

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## Core Primitives

### Accounts
Cartesio supports multiple account types:
- **Income sources** — external bank accounts linked via Plaid, Finicity, Method, or Spinwheel
- **Pods** — isolated sub-accounts for earmarking funds (e.g. a tax pod, an agent spending pod)
- **External accounts** — destination accounts for outbound transfers

### Rules
A rule is the unit of financial strategy. Each rule has:
- **Trigger** — when the rule fires: `MANUAL`, `ON_FUNDS_TRANSFERRED`, or `SCHEDULED`
- **Conditions** — optional guards: `BALANCE`, `DATE`, `TRANSFER_AMOUNT`
- **Action** — what happens: `percentage`, `fixed_amount`, `avalanche` (highest APR first), `snowball` (lowest balance first), `top_up`, `round_down`, `next_payment_minimum`
- **Transfer cap** — hard ceiling that can never be exceeded: `PER_TRANSFER`, `PER_MONTH`, `PER_YEAR`

Rules are created and updated by humans in the console. New or updated rules must be re-enabled by a human before agents can trigger them — agents cannot self-modify their rules.

### Transfers
Every rule execution produces a transfer record with full audit detail: what fired, when, what amount moved, and why.

### Webhooks
Cartesio emits webhooks on rule execution and transfer events for downstream integrations.

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## API

Base URL: `https://api.getsequence.io/api/v1`

Authentication: `Authorization: ApiKey YOUR_TOKEN`

### Key Endpoints
- `GET /accounts` — list all accounts with balances
- `GET /accounts/:id` — read a single account (balance in cents)
- `POST /rules/:id/trigger` — trigger a rule; returns an execution ID
- `GET /rules/:id/executions` — audit log for a rule

### Idempotency
All POST requests accept an `Idempotency-Key` header. Same key = same result. Prevents double-payments from retries.

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## Permission Model

API tokens are scoped at creation time:
- `TRIGGER_RULES` — which specific rule IDs the token can trigger
- `READ_ACCOUNTS` — which specific account IDs the token can read
- No `MANUAL_TRANSFER` permission exists — agents cannot move money outside of pre-approved rules

A compromised or hallucinating agent can only do the one thing its token was granted permission to do.

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## Integration Methods

1. **REST API** — standard HTTP from any language or framework
2. **MCP Server** — `npx @getsequence/mcp-server` — exposes Cartesio as tool calls inside Claude Code, Cursor, or any MCP-compatible agent
3. **n8n / Zapier** — HTTP request node, POST to `/rules/:id/trigger`

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## Example Rule Patterns

```
// Pay minimum on a loan, capped at $500/month
Trigger: MANUAL
Action: next_payment_minimum
Cap: $500 / PER_MONTH

// Move 28% of every income deposit to a tax pod
Trigger: ON_FUNDS_TRANSFERRED
Action: percentage (28%)
Source: income account

// Distribute $1,000/month across credit cards, highest APR first
Trigger: SCHEDULED (monthly)
Action: avalanche
Amount: $1,000

// Fund an agent's dedicated spending pod on demand
Trigger: MANUAL
Action: fixed_amount
Destination: agent-pod
```

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## Safety Guarantees

- **Transfer caps** — hard limits enforced server-side, not bypassable by the agent
- **Idempotency keys** — no accidental double-payments
- **Execution audit log** — every rule run is logged with full detail
- **Human review gate** — new and updated rules require human re-enablement; agents cannot self-modify

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## Links

- Landing page: https://cartesio.getsequence.io
- API docs: https://cartesio.getsequence.io/docs
- Console: https://app.getsequence.io
- Community (Discord): https://discord.gg/yheRpkXX
- Support: https://support.getsequence.io
- Waitlist: https://cartesio.getsequence.io (click "Get API Access")