Step 1 of holder sign-in. Pass your Base wallet address. Returns the SIWE message you need to sign with your wallet to prove you control the address.
AI agents call request-sign-in to retrieve information from Spines Underground without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a Read operation: it queries and retrieves authentication information (a SIWE message) based on wallet address input. No funds are moved, no data is modified, and no external operations are triggered. The tool is a prerequisite step for sign-in flow but itself performs no side effects.
From the tool's definition Tool returns a SIWE (Sign-In with Ethereum) message for wallet authentication. Description states it 'Returns the SIWE message' — a read operation that retrieves authentication data without modifying state or executing transactions.
Attacks that exploit this kind of access
Step 1 of holder sign-in. Pass your Base wallet address. Returns the SIWE message you need to sign with your wallet to prove you control the address. It is categorised as a Read tool in the Spines Underground MCP Server, which means it retrieves data without modifying state.
Register the Spines Underground MCP server in PolicyLayer and add a rule for request-sign-in: 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 Spines Underground. Nothing to install.
request-sign-in is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the request-sign-in 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 request-sign-in. 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.
request-sign-in is provided by the Spines Underground MCP server (lisamaraventano-spine/spines-underground). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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