Return the CausalLayer issuer registry, or one issuer record. The registry lists all trusted public-key fingerprints, key algorithms, validity windows, and the anchor-log repo for each active issuer. FREE — no API key required.
Part of the FaultKey · CausalLayer server.
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AI agents call query_issuer_registry to retrieve information from FaultKey · CausalLayer without modifying any data. This is common in research, monitoring, and reporting workflows where the agent needs context before taking action. Because read operations don't change state, they are generally safe to allow without restrictions -- but you may still want rate limits to control API costs.
Even though query_issuer_registry only reads data, uncontrolled read access can leak sensitive information or rack up API costs. An agent caught in a retry loop could make thousands of calls per minute. A rate limit gives you a safety net without blocking legitimate use.
Read-only tools are safe to allow by default. No rate limit needed unless you want to control costs.
{
"version": "1",
"default": "deny",
"tools": {
"query_issuer_registry": {}
}
}See the full FaultKey · CausalLayer policy for all 10 tools.
These attack patterns abuse exactly the kind of access query_issuer_registry gives an agent. Each links to the full case and the policy that stops it:
Other read tools across the catalogue. The same approach applies to each: allow, with a rate cap to control cost.
Return the CausalLayer issuer registry, or one issuer record. The registry lists all trusted public-key fingerprints, key algorithms, validity windows, and the anchor-log repo for each active issuer. FREE — no API key required.. It is categorised as a Read tool in the FaultKey · CausalLayer MCP Server, which means it retrieves data without modifying state.
Register the FaultKey · CausalLayer MCP server in PolicyLayer and add a rule for query_issuer_registry: 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 FaultKey · CausalLayer. Nothing to install.
query_issuer_registry 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 query_issuer_registry 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 query_issuer_registry. 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.
query_issuer_registry is provided by the FaultKey · CausalLayer MCP server (https://mcp.faultkey.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 10 FaultKey · CausalLayer tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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