Intercepta

https://github.com/Eth-Istanbul/Intercepta-BE

https://github.com/Eth-Istanbul/Intercepta-FE

https://www.canva.com/design/DAGyOczbpe8/sK-MbECaoTn48rfYlyE-QQ

Intercepta — Ethereum Guardian

Intercepta is a Chrome MV3 extension that safeguards Web3 activity by intercepting high‑risk Ethereum wallet operations and augmenting user decisions with real‑time, AI‑powered analysis.

Key capabilities

- Transaction interception: Wraps EIP‑1193 `provider.request` to gate methods like `eth_sendTransaction`, `eth_sign`, and `eth_signTypedData` before they reach the wallet.

- User approval workflow: Queues intercepted requests as pending, surfaces them in the popup, and requires explicit approve/reject to proceed.

- AI risk assessment: Sends pending transactions to a configured backend (`/tx/ai-analyze`) and displays risk level, fraud score, reasoning, warnings, and contract insights.

- Heuristic checks: Highlights risky function signatures, large value transfers, high gas settings, common DeFi actions, and signing prompts.

- Multi‑wallet awareness: Detects and wraps `window.ethereum` and any sub‑providers, with resilience to provider changes and late initialization.

- Clear UX: Organized pending vs. history views, filtering, auto‑refresh, and compact summaries of value, addresses, decoded function signatures, and token transfers.

How it works

- Content interception (`contents/ethereum-intercept.ts`): Overrides `request` for target methods, logs context (origin, user agent), and blocks until user decision. Auto‑rejects after 5 minutes if unanswered.

- Background coordination (`background.ts`): Persists pending items in `chrome.storage.local`, updates badge counts, and relays approvals/rejections back to the active tab.

- Popup review (`popup.tsx`): Lists pending/history, fetches AI analysis per transaction, and executes approve/reject actions that either proceed with the original wallet call or abort it.

- Utilities (`utils/transaction-analyzer.ts`, `utils/ai-analyzer.ts`): Local heuristics for quick risk cues and a typed client for AI analysis responses.

Privacy and security

- Local‑first state: Pending transactions are stored in `chrome.storage.local`; no unnecessary data leaves the browser.

- Explicit consent: No transaction proceeds without user approval; rejections never call the provider.

- Configurable AI endpoint: The analysis service URL is explicit and can be hosted under your control.

Technology stack

- Chrome MV3 with service worker background

- Plasmo content script in MAIN world for precise provider interception

- React + TypeScript for the popup UI, styled with Tailwind CSS

- Express backend for rapid prototyping