Anti-hallucination checker for legal references. POST text to verify every cited case (CourtListener), US Code section, and CFR regulation EXISTS, with canonical metadata + source URLs. POST quotes:[{citation,quote}] to deterministically verify an attributed QUOTE actually appears in the cited op...
AI agents call law.citation-check to retrieve information from Mcp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This is a read-only verification tool that queries legal databases and performs lookups without creating, modifying, or deleting data. It has no side effects beyond retrieving and comparing information. Even if an AI agent misuses it (e.g., over-queries), the blast radius is minimal—it only returns factual verification results. Low severity assigned due to benign informational purpose.
From the tool's definition Tool description explicitly states it 'verify[ies]' and 'checks facts (existence, quote presence)' against external sources (CourtListener, US Code, CFR).
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
Anti-hallucination checker for legal references. POST text to verify every cited case (CourtListener), US Code section, and CFR regulation EXISTS, with canonical metadata + source URLs. POST quotes:[{citation,quote}] to deterministically verify an attributed QUOTE actually appears in the cited opinion (ellipsis-aware) — catches fabricated quotations. Returns per-reference exists/quote-present + a summary. Checks facts (existence, quote presence), NOT whether a case legally supports a proposition. It is categorised as a Read tool in the Mcp MCP Server, which means it retrieves data without modifying state.
Register the MCP server in PolicyLayer and add a rule for law.citation-check: 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 Mcp. Nothing to install.
law.citation-check 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 law.citation-check 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 law.citation-check. 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.
law.citation-check is provided by the MCP server (@2sio/mcp). 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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