clinicaltrialsgov-mcp-server — Claude Code MCP server
Connects AI assistants to the ClinicalTrials.gov registry to query studies, pull outcome data, and pre-screen trials for patient profiles. No API key needed.
claude mcp add --transport http clinicaltrialsgov-mcp-server https://clinicaltrials.caseyjhand.com/mcpWhat clinicaltrialsgov-mcp-server does
The server provides access to clinical study records using seven tools and the clinicaltrials://{nctId} resource. It runs free-text and field queries covering conditions, sponsors, locations, or trial phases, and retrieves posted outcome data for completed trials.
While clinicaltrials_find_eligible filters recruiting studies by age, sex, and diagnosis, it skips inclusion and exclusion criteria analysis. Protocol criteria still require manual review. You can run it locally via npx over STDIO or attach directly to the hosted HTTP endpoint.
What it helps with
- search active clinical trials by condition, sponsor, or location coordinates
- retrieve full protocol records and reported study outcomes by NCT identifier
- count matching trials quickly without downloading entire study records
- screen candidate studies matching patient demographics and diagnoses
Example prompts for the agent
- Find recruiting phase 3 breast cancer studies within 50 miles of Boston
- Get published outcome measures and adverse event summary for NCT04280705
- Count how many completed stroke trials have posted results
How to install clinicaltrialsgov-mcp-server
1Platform CLI: remote server
claude mcp add --transport http clinicaltrialsgov-mcp-server https://clinicaltrials.caseyjhand.com/mcp2Platform CLI
claude mcp add --env CT_API_BASE_URL=<CT_API_BASE_URL> --env CT_REQUEST_TIMEOUT_MS=<CT_REQUEST_TIMEOUT_MS> --env CT_MAX_PAGE_SIZE=<CT_MAX_PAGE_SIZE> --env MCP_LOG_LEVEL=<MCP_LOG_LEVEL> --env MCP_TRANSPORT_TYPE=<MCP_TRANSPORT_TYPE> --transport stdio clinicaltrialsgov-mcp-server -- npx -y clinicaltrialsgov-mcp-serverReplace <…> with your own values. 4 more environment variables are in the server README
1Platform CLI: remote server
codex mcp add clinicaltrialsgov-mcp-server --url https://clinicaltrials.caseyjhand.com/mcp2Platform CLI
codex mcp add clinicaltrialsgov-mcp-server --env CT_API_BASE_URL=<CT_API_BASE_URL> --env CT_REQUEST_TIMEOUT_MS=<CT_REQUEST_TIMEOUT_MS> --env CT_MAX_PAGE_SIZE=<CT_MAX_PAGE_SIZE> --env MCP_LOG_LEVEL=<MCP_LOG_LEVEL> --env MCP_TRANSPORT_TYPE=<MCP_TRANSPORT_TYPE> -- npx -y clinicaltrialsgov-mcp-serverReplace <…> with your own values. 4 more environment variables are in the server README
Config file
{
"mcpServers": {
"clinicaltrialsgov-mcp-server": {
"url": "https://clinicaltrials.caseyjhand.com/mcp"
}
}
}{
"mcpServers": {
"clinicaltrialsgov-mcp-server": {
"command": "npx",
"args": [
"-y",
"clinicaltrialsgov-mcp-server"
],
"env": {
"CT_API_BASE_URL": "<CT_API_BASE_URL>",
"CT_REQUEST_TIMEOUT_MS": "<CT_REQUEST_TIMEOUT_MS>",
"CT_MAX_PAGE_SIZE": "<CT_MAX_PAGE_SIZE>",
"MCP_LOG_LEVEL": "<MCP_LOG_LEVEL>",
"MCP_TRANSPORT_TYPE": "<MCP_TRANSPORT_TYPE>"
}
}
}
}Replace <…> with your own values. 4 more environment variables are in the server README
Config file
{
"servers": {
"clinicaltrialsgov-mcp-server": {
"type": "http",
"url": "https://clinicaltrials.caseyjhand.com/mcp"
}
}
}{
"servers": {
"clinicaltrialsgov-mcp-server": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"clinicaltrialsgov-mcp-server"
],
"env": {
"CT_API_BASE_URL": "<CT_API_BASE_URL>",
"CT_REQUEST_TIMEOUT_MS": "<CT_REQUEST_TIMEOUT_MS>",
"CT_MAX_PAGE_SIZE": "<CT_MAX_PAGE_SIZE>",
"MCP_LOG_LEVEL": "<MCP_LOG_LEVEL>",
"MCP_TRANSPORT_TYPE": "<MCP_TRANSPORT_TYPE>"
}
}
}
}Replace <…> with your own values. 4 more environment variables are in the server README
1Platform CLI: remote server
gemini mcp add -t http clinicaltrialsgov-mcp-server https://clinicaltrials.caseyjhand.com/mcp2Platform CLI
gemini mcp add -e CT_API_BASE_URL=<CT_API_BASE_URL> -e CT_REQUEST_TIMEOUT_MS=<CT_REQUEST_TIMEOUT_MS> -e CT_MAX_PAGE_SIZE=<CT_MAX_PAGE_SIZE> -e MCP_LOG_LEVEL=<MCP_LOG_LEVEL> -e MCP_TRANSPORT_TYPE=<MCP_TRANSPORT_TYPE> clinicaltrialsgov-mcp-server npx -y clinicaltrialsgov-mcp-serverReplace <…> with your own values. 4 more environment variables are in the server README
Step by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about clinicaltrialsgov-mcp-server
How to install clinicaltrialsgov-mcp-server in Claude Code?
Run claude mcp add --transport http clinicaltrialsgov-mcp-server https://clinicaltrials.caseyjhand.com/mcp for the remote HTTP endpoint, or execute `claude mcp add --env CT_API_BASE_URL=<CT_API_BASE_URL> --env CT_REQUEST_TIMEOUT_MS=<CT_REQUEST_TIMEOUT_MS> --env CT_MAX_PAGE_SIZE=<CT_MAX_PAGE_SIZE> --env MCP_LOG_LEVEL=<MCP_LOG_LEVEL> --env MCP_TRANSPORT_TYPE=<MCP_TRANSPORT_TYPE> --transport stdio clinicaltrialsgov-mcp-server -- npx -y clinicaltrialsgov-mcp-server to run locally via npx`.
Does clinicaltrialsgov-mcp-server require an API key?
No API token is required. The server queries the public endpoints of ClinicalTrials.gov directly.
Does the patient matching tool evaluate inclusion criteria?
No, clinicaltrials_find_eligible only matches basic demographic values and conditions. It does not parse or verify full protocol inclusion and exclusion criteria.
