# Execution

> Markdown export of the Gearbox Protocol documentation page for agents and retrieval systems.

Canonical page: https://docs.gearbox.finance/developers/ga-execution
Source file: content/developers/ga-execution.mdx
Section router: https://docs.gearbox.finance/developers/llms.txt
Section full export: https://docs.gearbox.finance/developers/llms-full.txt

How agents interact with the Gearbox protocol on-chain — and why it's safe.

## The Security Model

A core principle of Gearbox Agentic: **the SDK builds transactions, but never signs them**. Transaction construction (what to do) is separated from transaction execution (actually doing it). This creates a clear security boundary.

Every transaction goes through **preview** before execution:

1. **Build** — `sdk.positions.prepareOpen()` → produces a `RawTx { to, calldata, value }`
2. **Preview** — `sdk.previewTransaction(rawTx)` → simulates the exact bytes, returns success, health factor, actions, balance changes, warnings
3. **Validate** — agent (or human) checks: success = true, HF > threshold, no critical warnings
4. **Execute** — sign and send via wallet

The same bytes that were previewed are the bytes that go on-chain. No deviation.

## Two Execution Modes

| Mode | Trust Level | Best For |
| --- | --- | --- |
| [**Human-in-the-Loop**](https://docs.gearbox.finance/developers/ga-human-loop) | Agent proposes, human approves | High-value positions, institutional compliance, initial trust building |
| [**Bot Execution**](https://docs.gearbox.finance/developers/ga-bot-execution) | Agent executes autonomously within bounds | Rebalancing, liquidation monitoring, automated management |

Both modes use the same preview mechanism. The difference is who signs.

## Learn More

- [Human-in-the-Loop](https://docs.gearbox.finance/developers/ga-human-loop) — verify.gearbox.finance approval flow
- [Bot Execution](https://docs.gearbox.finance/developers/ga-bot-execution) — bounded on-chain permissions
- [The Agent Loop](https://docs.gearbox.finance/developers/ga-agent-loop) — how Preview and Execute fit in the 6-step cycle