Monitor on-chain contracts for anomalous transactions. Checks for large transfers, ownership changes, unusual methods, and selfdestruct calls via Blockscout API v2. TRIGGER when: user asks about contract monitoring, "check this contract", on-chain alerts, "any suspicious transactions", or invokes "/sentinel". DO NOT TRIGGER when: user is working on sentinel agent code itself.

Sentinel

On-chain contract monitor. 4 alert rules (large transfers, ownership changes, unusual methods, selfdestruct) across 8 chains via Blockscout API v2.

What You Get

Alert list: large transfers, ownership changes, unusual methods, selfdestruct calls
JSONL alert log at ~/.local/share/sentinel/alerts.jsonl
macOS notifications for continuous watch mode

CLI Usage

# One-shot contract check
sentinel check --address 0x... --chain 1

# Check from a specific block
sentinel check --address 0x... --chain 8453 --since-block 12345678

# Continuous monitoring from config
sentinel watch --config sentinel.toml

# View recent alerts
sentinel alerts --limit 20

Supported Chains

EVM-only. Not available for native Solana or Tron -- use coingecko skill for token data on those chains.

Chain	ID	Chain	ID
Ethereum	1	Arbitrum One	42161
Polygon	137	OP Mainnet	10
Base	8453	zkSync Era	324
Gnosis	100	Scroll	534352
Celo	42220	Mode	34443
Neon EVM (Solana)	245022934

MCP Server

sentinel serve

Configure MCP

Add to ~/.mcp.json:

{
  "mcpServers": {
    "sentinel": {
      "command": "sentinel",
      "args": ["serve"]
    }
  }
}

MCP Tools

Tool	Description
`sentinel_check`	Check a contract for anomalous transactions
`sentinel_alerts`	Show recent alerts from the local log

Install

cd agents/sentinel
pip install -e .

No API keys required -- uses public Blockscout API v2 endpoints.