Search for clinical trial studies from ClinicalTrials.gov. Supports full-text and field-specific queries, status/phase/geographic filters, pagination, sorting, and field selection. Use the fields parameter to reduce payload size — full study records are ~70KB each.
Risk signalsAccepts freeform code/query input (query) · High parameter count (17 properties)
Part of the Clinicaltrialsgov server.
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AI agents call clinicaltrials_search_studies to retrieve information from Clinicaltrialsgov 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 clinicaltrials_search_studies 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": {
"clinicaltrials_search_studies": {}
}
}See the full Clinicaltrialsgov policy for all 7 tools.
These attack patterns abuse exactly the kind of access clinicaltrials_search_studies 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.
Search for clinical trial studies from ClinicalTrials.gov. Supports full-text and field-specific queries, status/phase/geographic filters, pagination, sorting, and field selection. Use the fields parameter to reduce payload size — full study records are ~70KB each.. It is categorised as a Read tool in the Clinicaltrialsgov MCP Server, which means it retrieves data without modifying state.
Register the Clinicaltrialsgov MCP server in PolicyLayer and add a rule for clinicaltrials_search_studies: 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 Clinicaltrialsgov. Nothing to install.
clinicaltrials_search_studies 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 clinicaltrials_search_studies 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 clinicaltrials_search_studies. 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.
clinicaltrials_search_studies is provided by the Clinicaltrialsgov MCP server (cyanheads/clinicaltrialsgov-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 7 Clinicaltrialsgov tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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