VSAC FHIR (BYOK)

VSAC FHIR (BYOK) — connector documentation

• MCP endpoint: https://byok-vsac.connectorbay.com/mcp
• REST API: POST https://byok-vsac.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://byok-vsac.connectorbay.com/openapi.json
• Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
• Authentication: your own VSAC FHIR UMLS API key, sent in the X-Upstream-Key header of every request (never stored, logged or cached)
• Health: https://byok-vsac.connectorbay.com/health · Tool schemas: https://byok-vsac.connectorbay.com/tools.json
• Publisher: Unify Dynamics LLC · connectorbay.com/byok-vsac · agent@connectorbay.com

What VSAC FHIR (BYOK) is for

VSAC FHIR (BYOK) lets an AI assistant read your own VSAC FHIR data through the VSAC FHIR API with a key you supply (UMLS API key). Read-only: 6 tools (get_value_set, expand_value_set, validate_code_in_value_set, get_code_system, lookup_code, check_subsumption). The BYOK key travels with each request, is used for that one call only and is never stored, logged or cached; it is only ever sent to cts.nlm.nih.gov. Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by VSAC FHIR. VSAC FHIR and its logos are trademarks of their owners and are used only to say which service the connector works with.

Ask your assistant things like:

• "Describe VSAC value set 2.16.840.1.113883.3.464.1003.113.11.1090"
• "List the codes in VSAC value set 2.16.840.1.113883.3.464.1003.113.11.1090 that mention spine"
• "Is ICD-10-CM code M45.0 in VSAC value set 2.16.840.1.113883.3.464.1003.113.11.1090?"
• "Describe the CDCREC code system in VSAC"
• "What is LOINC code 1963-8?"
• "Does SNOMED CT code 29857009 subsume 10000006?"

What it does

• get_value_set: Get the definition of a VSAC value set by OID: title, status, version, publisher, description and its compose rules.
• expand_value_set: List the codes in a VSAC value set (code, display, code system, version), optionally filtered by text; at most 1,500 codes per code system.
• validate_code_in_value_set: Check whether a code of a given code system belongs to a VSAC value set.
• get_code_system: Get details of a code system supported by VSAC by its id (for example CDCREC): name, URL, status, content mode and publisher.
• lookup_code: Look up one code in a code system (LOINC, SNOMED CT, ICD-10-CM, RxNorm and others): display name, version and properties.
• check_subsumption: Test whether one code subsumes another in a hierarchical code system (SNOMED CT, ICD-10-CM and others).

BYOK key

You bring your own VSAC FHIR UMLS API key (https://uts.nlm.nih.gov/uts/profile). Your assistant sends it in the X-Upstream-Key header with each request. ConnectorBay uses it for that one call only: it is never stored, logged or cached, never shown in an answer, and it is only sent to cts.nlm.nih.gov over https, with no redirects followed. Create a key with the fewest permissions the tools need (read-only if the provider offers it), and revoke it at the provider whenever you like.

Data sources

• https://www.nlm.nih.gov/vsac/support/usingvsac/vsacfhirapi.html (the API this connector calls, with a BYOK key)

Live from the VSAC FHIR API (cts.nlm.nih.gov) with a BYOK key; documentation: https://www.nlm.nih.gov/vsac/support/usingvsac/vsacfhirapi.html. Endpoints checked against that documentation on 2026-10-16.

What it is not

Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by VSAC FHIR. VSAC FHIR and its logos are trademarks of their owners and are used only to say which service the connector works with. It is read-only: it never creates, changes, sends or deletes anything in your VSAC FHIR account.

Built for: Worldwide. Languages: English.

VSAC FHIR (BYOK) — Privacy Policy

Effective 24 October 2026. Unify Dynamics LLC ("we", "us"), Menlo Park, California.

What VSAC FHIR (BYOK) is. VSAC FHIR (BYOK) is a connector (an MCP server and REST API) that an AI assistant calls on your behalf to read your own VSAC FHIR data: Read VSAC value sets and code systems through the NLM FHIR terminology service: expand value sets, validate and look up codes, check subsumption, with your own UMLS API key. You bring your own VSAC FHIR UMLS API key; the assistant sends it to us with each request.

BYOK key. The key you supply is used to make the one VSAC FHIR call you asked for. Our application does not store it, write it to a log, put it in a cache, or share it. It is sent only to cts.nlm.nih.gov, over https, and is removed from any text we return to you or your assistant. We do not follow redirects with your key. If VSAC FHIR rejects it, we say so without repeating it.

What we receive. The arguments of each tool call, the BYOK key (for that call only), the technical headers needed to serve the request (an IP address or a client identifier supplied by the assistant) and standard server logs. What VSAC FHIR receives. The request we make on your behalf, including the key and the arguments, under VSAC FHIR's own terms and privacy policy. VSAC FHIR acts at your direction and is the only recipient of the data of your request besides our hosting provider.

What we return. The answer VSAC FHIR gives for your request, trimmed to the fields the tool documents. We do not keep it: it is returned to your assistant and not stored, cached or used to train anything.

What we do not do. We do not build a profile, sell or share personal information, or keep your VSAC FHIR data. Rate-limit counters (a client identifier and timestamps) are held in memory for at most 24 hours. Hosting access logs (IP addresses, request paths and status codes) are kept for up to 30 days for security and abuse prevention; our application adds no request headers or bodies to them.

Sub-processors. VSAC FHIR (the API you call with a BYOK key, at your direction). Hosting: Vercel (United States regions).

Your rights. Because we store no personal data beyond short-lived logs, requests to access, correct or delete data are usually satisfied automatically; you can still contact agent@connectorbay.com and we will respond within 30 days. Revoke your key at VSAC FHIR at any time to end all access.

Children. VSAC FHIR (BYOK) is a general-audience service operated by the adult using the assistant, under VSAC FHIR's own age rules.

Changes. We will post changes here with a new effective date.

VSAC FHIR (BYOK) — Terms of Service

Effective 24 October 2026. These terms govern use of the VSAC FHIR (BYOK) connector ("the Service") operated by Unify Dynamics LLC ("we", "us").

1. The Service. VSAC FHIR (BYOK) provides: Read VSAC value sets and code systems through the NLM FHIR terminology service: expand value sets, validate and look up codes, check subsumption, with your own UMLS API key. It is accessed through an AI assistant or directly over MCP or HTTP, and is read-only.
2. Your own key, your own account. You must use your own VSAC FHIR credentials and only access data you are allowed to access. VSAC FHIR's terms apply to your use of VSAC FHIR; you are responsible for complying with them, including any rate limits and permitted uses. Do not share a key you do not own.
3. Independent. Unofficial connector by Unify Dynamics LLC: not affiliated with, endorsed by or sponsored by VSAC FHIR. VSAC FHIR and its logos are trademarks of their owners and are used only to say which service the connector works with.
4. No advice, no guarantees. Output is the data VSAC FHIR returns, lightly trimmed; it may be incomplete, delayed or changed by VSAC FHIR. Check important facts at the source.
5. Read-only. The Service does not create, change, send or delete anything in your VSAC FHIR account.
6. Acceptable use. Automated use within the published rate limits is welcome. Do not use the Service to access data you are not entitled to, to circumvent VSAC FHIR's controls, or to attack any system.
7. Availability. The Service is provided "as is" without warranty. We may change, limit or discontinue it at any time; VSAC FHIR may change or end its API at any time.
8. Data. Our Privacy Policy describes what we process. In short: the BYOK key is used for the one call and not stored or logged.
9. Pro keys. Optional ConnectorBay Pro API keys are issued at our discretion and are separate from your VSAC FHIR key.
10. Liability. To the fullest extent permitted by law, Unify Dynamics LLC is not liable for any loss arising from use of or reliance on the Service, including any action VSAC FHIR takes on your account. Our total liability is limited to US $100.
11. Governing law. California law; venue in San Mateo County, California.
12. Contact. Unify Dynamics LLC · agent@connectorbay.com · https://connectorbay.com/byok-vsac

VSAC FHIR (BYOK) support

Email agent@connectorbay.com. We answer within two business days.

• MCP endpoint: https://byok-vsac.connectorbay.com/mcp
• REST API: https://byok-vsac.connectorbay.com/openapi.json
• Live status: https://byok-vsac.connectorbay.com/health

When you report a problem, include the question you asked your agent, roughly when, and which agent you used (for example Claude, ChatGPT or Gemini). Never send us passwords, account numbers or ID numbers. VSAC FHIR (BYOK) never asks for them.