> ## Documentation Index
> Fetch the complete documentation index at: https://docs.portir.xyz/llms.txt
> Use this file to discover all available pages before exploring further.
# How it works
> The path from a tap on Buy (or a due plan) to a recorded transaction.
## The building blocks
| Piece | Role |
| - | - |
| **Binance RWA Data API** | US session, halts, exchange reference price, issuer multipliers, catalog of 500+ stocks and ETFs |
| **Binance Trading API** | Executable quotes and swap calldata over PancakeSwap liquidity (user buys on mainnet) |
| **The Guard** | Pure verdict logic: GO / WARN / BLOCK with a reason |
| **PlanRegistry** | Plans, sell rules, funding pulls and run history. Holds no funds between calls |
| **LoanGuard** | Capped, on-chain-checked repayments of Venus loans from the borrower's buffer |
| **Portir agent** (BNB Agent Studio) | Executor every 15 min, Loan Guard loop every 5 min, MCP / x402 / A2A faces |
| **Binance Agentic Wallet** | The agent's hands on mainnet: MPC wallet with limits set in the Binance App |
## A manual buy
```mermaid theme={null}
sequenceDiagram
participant U as You
participant A as Portir app
participant G as Guard
participant B as Binance APIs
participant W as Your wallet
U->>A: Buy $50 of NVDA
A->>B: session, reference price, on-chain price per issuer
A->>G: snapshot
G-->>A: GO / WARN / BLOCK + reason
A->>B: quote from the cheapest fair issuer
B-->>A: approval + swap calldata (0.5% minimum output)
A->>W: sign
W-->>U: shares in your wallet
```
Nothing is sent from a server. The app only prepares calldata; your wallet signs.
## A plan run
```mermaid theme={null}
flowchart LR
S[Scan every 15 min] --> D{Plan due?}
D -- no --> S
D -- yes --> F{Funded? allowance and balance}
F -- no --> X[Not recorded, nothing spent]
F -- yes --> G{Fair enough? not BLOCK, or with smart timing: GO and market open}
G -- no, inside the window --> W[Waited, logged sparingly]
G -- yes --> N{News check}
N -- hold --> W
N -- buy --> P[Pull at most the plan amount via PlanRegistry]
P --> B[Buy each holding]
B --> T[Send shares to the owner]
T --> R[recordRun Executed + reason]
G -- window over: 48h, or 7 days for once --> K[Skipped + reason]
```
## A loan rescue
```mermaid theme={null}
flowchart LR
L[Every 5 min] --> R[Read each guarded position]
R --> C{usedBps past trigger?}
C -- no --> L
C -- yes --> K[LoanGuard re-checks on-chain]
K --> P[repayBorrowBehalf from the borrower's buffer, capped]
P --> T[Back to the target, rescue recorded]
```
The agent decides; the contracts enforce. A leaked agent key can take at most one run's amount per due plan, and can only repay a borrower's own debt, capped. See the [security model](/learn/security-model).
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