A deterministic risk layer for autonomous trading agents.

Quickstart

Get up and running in under 2 minutes. This complete Python script demonstrates how to request a nonce, sign it, authenticate, and run a pre-trade risk check.

import requests
from eth_account import Account
from eth_account.messages import encode_defunct

# Configuration
BASE_URL = "https://backendai-x4m1.onrender.com"
PRIVATE_KEY = "0x..."  # Your agent's private key
account = Account.from_key(PRIVATE_KEY)
wallet_address = account.address

# Step 1: Get authentication nonce
res = requests.get(f"{BASE_URL}/api/v1/auth/nonce", params={"address": wallet_address})
res.raise_for_status()
message_to_sign = res.json()["message"]

# Step 2: Sign EIP-191 message
message = encode_defunct(text=message_to_sign)
signature = Account.sign_message(message, private_key=PRIVATE_KEY).signature.hex()

# Step 3: Exchange signature for access token
auth_res = requests.post(f"{BASE_URL}/api/v1/auth/wallet", json={
    "address": wallet_address,
    "signature": signature
})
auth_res.raise_for_status()
token = auth_res.json()["access_token"]

# Step 4: Analyze a trade before submission
headers = {"Authorization": f"Bearer {token}"}
trade_payload = {
    "wallet": wallet_address,
    "asset": "NVDA",
    "side": "buy",
    "amount": 10.0,
    "contract_address": "0xd0601CE157Db5bdC3162BbaC2a2C8aF5320D9EEC",
    "request_id": "quickstart-test-001"
}

trade_res = requests.post(f"{BASE_URL}/api/v1/analyze/trade", json=trade_payload, headers=headers)
print("Trade Verdict Response:", trade_res.json())

Why Collar exists

Robinhood Chain is a blockchain built for autonomous trading agents. Agents on it are fast, tireless, and increasingly handling real money.

They are also probabilistic. Every LLM-based agent can hallucinate a token address, ignore its own risk rules under pressure, or be talked into a bad trade by a prompt injection hidden in some piece of data it happened to read. When that happens, the agent does not stop. It executes.

The existing risk tooling was not built for this. Most platforms in the space use machine learning to monitor activity across many chains. That is the right model for institutional security. It is not designed for the independent agent developer who needs a deterministic second opinion in one HTTP call.

Collar does not try to be smarter than the agent. It tries to be predictable in a way the agent cannot be. It sits outside the agent's runtime, at the last point before a trade is signed, and returns one of three answers.

When to use Collar

How Collar differs

There are already tools that watch on-chain activity. Most of them are excellent — for their intended audience. Collar is built around four choices that put it in a different shape.

Collar is not claiming to be the first risk tool on Robinhood Chain. It is claiming to be a specific shape of one: API-first, deterministic, and stock-token aware.

Overview

Collar evaluates trade requests against a deterministic policy before the integrating agent submits them for execution. Each request is checked against:

• USD trade notional limits based on wallet COLR tier.
• Real-time Chainlink oracle prices for the traded asset.
• Corporate-action pause state (oraclePaused()) for tokenized equities.
• Feed staleness relative to heartbeat.
• Asset restrictions configured for eligible tiers.
• Potential runaway activity based on request frequency.

COLR is an access and tier-gating token

COLR is not the trade currency. Agents can submit trades involving other supported assets, such as ETH, USDG, or tokenized equities. The wallet's COLR balance determines the access tier:

While COLR has not launched, the API grants a default Tier 1 to every authenticated wallet. See preview-tier testing below.

Verdicts

Verdicts are advisory. Collar does not currently enforce the decision at the blockchain or sequencer level.

Asset registry

Returns every symbol and its official contract address. Robinhood adds new tokens over time — refresh this periodically rather than caching indefinitely.

[
  { "symbol": "NVDA", "contract_address": "0xd0601CE157Db5bdC3162BbaC2a2C8aF5320D9EEC", "is_native": false },
  { "symbol": "ETH",  "contract_address": "NATIVE", "is_native": true }
]

Blocked-asset policy (Tier 2+)

Returns the wallet's current policy configuration.

{
  "blocked_assets": ["MEME", "XYZ"],
  "editable": true
}

Updates the blocked-asset list for Tier 2 and Tier 3 wallets.

{ "blocked_assets": ["MEME", "XYZ"] }

Trade requests against a blocked asset receive a deny verdict.

Rate limiting and runaway-agent detection

Collar tracks request frequency over a rolling 60-second window, per wallet, in Redis.

• Tier 1: warn above 5 trades/min, deny above 15.
• Tier 2: warn above 10, deny above 25.
• Tier 3: warn above 20, deny above 50.

There is no separate API-level rate limit on /analyze/trade beyond this — it is the runaway-agent protection.

While COLR has not launched, every wallet is granted a default Tier 1. To test Tier 2 or Tier 3 behavior, add the header X-Preview-Tier: 2 (or 3). This header is silently ignored once COLR launches and a real balance check takes over.

Authentication

Authentication uses wallet signatures rather than API keys. The same private key the agent already holds for trading is used to sign a one-time challenge.

Request a one-time nonce and the exact message to sign. The nonce expires in 5 minutes and can only be used once.

Submit the wallet address and an EIP-191 signature of the message from the previous step.

{
  "address": "0x1234567890123456789012345678901234567890",
  "signature": "0x..."
}

{
  "access_token": "eyJ...",
  "expires_in_seconds": 3600,
  "preview_mode": true
}

Authenticated API requests use Authorization: Bearer <access_token>. To end a session immediately, call:

Analyze a trade

Submit a trade request for deterministic policy evaluation. Requires authentication.

Request

{
  "wallet": "0x1234567890123456789012345678901234567890",
  "asset": "NVDA",
  "side": "buy",
  "amount": 12.5,
  "contract_address": "0xd0601CE157Db5bdC3162BbaC2a2C8aF5320D9EEC",
  "request_id": "a1b2c3d4-..."
}

Fields

Response

{
  "decision": "allow",
  "reasons": ["All guardrail checks passed"],
  "tier": 1,
  "max_trade_usd": 5000.0,
  "calculated_notional_usd": 2728.72,
  "price_usd": 218.298,
  "price_source": "oracle",
  "risk_score": 18,
  "timestamp": 1757520000,
  "request_id": "a1b2c3d4-..."
}

Error responses

What's next

Verified against mainnet

The oracle path has been tested end-to-end against live Chainlink feeds on Robinhood Chain. Stock Token prices, oraclePaused() state, and staleness windows have all been exercised against real mainnet data.

Independence

Collar Guardrail is an independent third-party application built to provide a risk layer for autonomous trading workflows.

It is not built, operated, sponsored, or endorsed by Robinhood.

Robinhood Chain is the underlying network referenced by the integration. COLR is a separate token used for access and tier gating.