Create a free-tier 0xArchive account and get an API key using a signed SIWE message.
AI agents use web3_signup to create or update resources in 0xarchive — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your 0xarchive environment.
This tool creates persistent account and credential objects, which is a Write operation. Severity is medium because: (1) it only creates free-tier access with limited scope, (2) creation is reversible (account can be deleted), and (3) blast radius is modest—an AI agent misusing this could spam account creation but cannot access financial assets or critical infrastructure.
From the tool's definition Tool creates a new account and generates an API key ('Create a free-tier 0xArchive account and get an API key'). These are irreversible account creation actions that modify backend state.
Documented attack patterns abuse exactly the kind of access web3_signup gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and 0xarchive, and nothing reaches the server without passing your rules. This is the rule we recommend for web3_signup:
{
"version": "1",
"default": "deny",
"tools": {
"web3_signup": {
"limits": [
{
"counter": "web3_signup_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}web3_signup stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Create a free-tier 0xArchive account and get an API key using a signed SIWE message. It is categorised as a Write tool in the 0xarchive MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the 0xarchive MCP server in PolicyLayer and add a rule for web3_signup: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches 0xarchive. Nothing to install.
web3_signup is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the web3_signup rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for web3_signup. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
web3_signup is provided by the 0xarchive MCP server (0xarchiveio/0xarchive-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from 0xarchive, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
5 0xarchive tools catalogued and risk-classified — across an index of 43,000+ MCP servers.