ClinicalTrials.gov MCP by usefulapi is answering right now. Last checked 2 min ago. It exposes 7 tools. Last commit 25 Oct 2026.
Search and read ClinicalTrials.gov studies, sites and outcomes.
Uptime history
27 days of history
27 days agonow
100.0%
Uptime 24h
92 of 92 checks
7
Tools
read from the server
330 ms
Response time
average over 24h
0
Stars
last commit 25 Oct 2026
What changed 33
Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 30 September 2026. No other catalogue keeps this.
25 Oct
a tool changed version4 times that day
24 Oct
a tool changed version3 times that day
23 Oct
a tool changed version
22 Oct
7 tools appeared
clinicaltrialsgov_count_studies, clinicaltrialsgov_get_api_version, clinicaltrialsgov_get_studies_stats and 4 more
22 Oct
7 tools disappeared
count_studies, get_api_version, get_studies_stats and 4 more
22 Oct
a tool changed version2 times that day
20 Oct
a tool changed version3 times that day
13 Oct
a tool changed version
9 Oct
a tool changed version4 times that day
30 Sep
a tool changed version
and 11 more, back to 30 September 2026
Tools have disappeared from this server
A tool that vanishes takes a piece of your agent with it, and the change arrives silently. Watch this server and every such change lands in your inbox.
Connect this server
Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 2 min ago.
run in your terminal
claude mcp add clinicaltrialsgov --transport http https://clinicaltrialsgov.usefulapi.io/mcpSettings → Connectors → Add custom connector, then paste this address
https://clinicaltrialsgov.usefulapi.io/mcp~/.codex/config.toml
[mcp_servers.clinicaltrialsgov]
url = "https://clinicaltrialsgov.usefulapi.io/mcp".cursor/mcp.json
{
"mcpServers": {
"clinicaltrialsgov": {
"url": "https://clinicaltrialsgov.usefulapi.io/mcp"
}
}
}.vscode/mcp.json
{
"servers": {
"clinicaltrialsgov": {
"type": "http",
"url": "https://clinicaltrialsgov.usefulapi.io/mcp"
}
}
}Available tools 7
Read directly from the server with tools/list, grouped by what they act on.
If a tool disappears, we record the date.
clinicaltrialsgov
clinicaltrialsgov_count_studies
Return only the total NUMBER of studies matching a query, without fetching any records. Accepts the same query terms and filters as clinicaltrialsgov_search_studies (term, condition, intervention, title, location, sponsor, status, geoFilter, advanced). Returns { totalCount }. GET /studies with countTotal=true and pageSize=1.
clinicaltrialsgov_get_api_version
Return the ClinicalTrials.gov API version and the timestamp of the underlying data snapshot: { apiVersion, dataTimestamp }. GET /version.
clinicaltrialsgov_get_studies_stats
Return overall study-size statistics across the registry: { totalStudies, averageSizeBytes, percentiles, ranges, largestStudies }. Useful for understanding data volume. GET /stats/size.
clinicaltrialsgov_get_study
Fetch a single ClinicalTrials.gov study by its NCT id (format NCT######## — the letters 'NCT' followed by digits, e.g. NCT00841061). Returns the full study object { protocolSection, derivedSection?, hasResults? }. Use `fields` to return only specific fields/modules. GET /studies/{nctId}.
clinicaltrialsgov_get_study_metadata
Return the ClinicalTrials.gov study data model as a tree of module nodes (each with name/title/type/children). Use this to explore what fields/modules exist and their nesting, to build `fields` selections or `sort`/filter expressions. GET /studies/metadata.
clinicaltrialsgov_list_field_values
Discover valid values / enums for one or more study fields. Returns per-field value statistics — for each field: its type, unique-value count and topValues [{value, studiesCount}]. Great for finding valid enum values (e.g. OverallStatus, Phase) before building a filter. GET /stats/field/values.
clinicaltrialsgov_search_studies
Search the ClinicalTrials.gov v2 study registry. Provide any combination of query terms (condition, intervention, title, location, sponsor, general term) — multiple query.* terms are ANDed together — plus optional filters (status, geo, advanced Essie expression, explicit NCT ids). Returns { totalCount?, studies: [...], nextPageToken? }. Use `fields` to trim the response to specific fields/modules, `sort` to order (e.g. '@relevance', 'LastUpdatePostDate:desc', 'EnrollmentCount:desc'), and pageSize/pageToken to page. GET /studies.
Tools removed
Tools this server used to expose. Anything built against them stopped working on the day they went.
count_studies
removed 22 Oct 2026
get_api_version
removed 22 Oct 2026
get_studies_stats
removed 22 Oct 2026
get_study
removed 22 Oct 2026
get_study_metadata
removed 22 Oct 2026
list_field_values
removed 22 Oct 2026
search_studies
removed 22 Oct 2026
Endpoints
| URL | Transport | State | Latency | Checked |
|---|---|---|---|---|
| https://clinicaltrialsgov.usefulapi.io/mcp | streamable-http | answering | 136 ms | 2 min ago |
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ClinicalTrials.gov MCP by usefulapi — questions
Answers built from our own checks of this server.
What can ClinicalTrials.gov MCP by usefulapi do?
It exposes 7 tools, read directly from the server on our last check. Among them: clinicaltrialsgov_count_studies, clinicaltrialsgov_get_api_version, clinicaltrialsgov_get_studies_stats, clinicaltrialsgov_get_study, clinicaltrialsgov_get_study_metadata, clinicaltrialsgov_list_field_values and 1 more. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README.
How MCP servers expose tools in the first place →
Is ClinicalTrials.gov MCP by usefulapi working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 330 ms. The bar chart above shows every period we have measured.
Did ClinicalTrials.gov MCP by usefulapi ever remove tools?
Yes. count_studies, get_api_version, get_studies_stats, get_study and 3 more are no longer exposed — we recorded the date each one disappeared. A tool vanishing usually means a breaking change for anything that depended on it.
How do I connect ClinicalTrials.gov MCP by usefulapi?
Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does ClinicalTrials.gov MCP by usefulapi need an API key?
No. ClinicalTrials.gov MCP by usefulapi completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 7 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is ClinicalTrials.gov MCP by usefulapi?
It answers our handshake in 330 ms on average, which is faster than 49% of all working MCP servers we measure. The comparison comes from our own checks across the whole registry, every 15 minutes.
Is ClinicalTrials.gov MCP by usefulapi open source?
The code is open source: it is published under the MIT licence, written in JavaScript, 0 stars on GitHub and 1 open issue. The licence covers the code in the repository, not the hosted service at clinicaltrialsgov.usefulapi.io, which runs on its operator's own terms.