Choose the smallest useful MCP tool catalog

MCP gives an agent a standard way to discover and call tools. Product teams still decide which tools exist, what data they expose, and which scopes they require. Focused queries create clearer authorization and evaluation than unrestricted access to an entire record.

Implement discovery, authorization, and errors as one flow

Publish a machine-readable manifest and an OpenAPI contract, then let the agent list tools after authorization. Start with functions such as reading health context, listing sources, querying trends, or locating providers. Require explicit endpoint grants for imports, analysis creation, external connections, export, deletion, or paid compute.

Use an approval flow that displays the agent name and never puts a key in a redirect URL. The agent should retain a private polling secret, receive a key once after approval, and store it with restrictive file permissions.

A practical first tool set

Start with a short catalog that matches complete user jobs. Useful examples include read latest health context, compare a named biomarker, start an upload, check analysis status, build a dashboard specification, and search providers. Split tools when they require different permissions or failure handling.

Describe required fields, supported units, limits, asynchronous states, and safety boundaries in the schema. Return structured errors with a stable code, plain-language explanation, and next action. Agents recover better when the fix is explicit.

Test the authorization boundary

A remote MCP server should validate that the token was issued for the correct audience and requested operation. Token passthrough to downstream services can expose credentials and undermine the trust boundary. Exchange or mint credentials designed for each service.

Add negative tests for another user's source, another organization's analysis, an expired grant, a tool outside the endpoint grant, and a revoked agent. A successful happy path proves connectivity; these failures prove isolation.

  • tools/list returns only allowed capabilities
  • tools/call validates schema and scope
  • Errors expose a safe fix without leaking data
  • Revocation blocks the next call
  • Logs identify user, agent, tool, request, and result

MCP health server release gate

  • Authorization follows the current MCP specification for the chosen transport
  • Token audience and scope validation are tested
  • Tool schemas contain limits and examples
  • Writes are idempotent where retries are possible
  • Sensitive values never appear in prompts, URLs, or client logs
  • The server supports revocation and audit review

Expose the same health operations through MCP

WellNizz publishes an agent manifest and OpenAPI 3.1 contract, supports MCP tools/list and tools/call, and maps tools to scopes and endpoint grants. The same capabilities are available through REST, with both transports using the same health operations.

Keep credentials out of prompts and URLs

MCP connectivity does not make an agent trustworthy by itself. Review the tools, permissions, data retention, and model behavior of every client before connecting sensitive health data.

Editorial sources

Read the primary guidance

These sources support the technical and health boundaries in this article. Provider prices, availability, and product terms should always be checked at the provider before purchase.

Questions, answered

FAQ

What tools should an MCP health agent start with?

Start with focused, read-only tools such as querying health context, trends, sources, or provider options. Add consequential tools only when there is a clear approval and audit model.

How should an agent get a health-data key?

Through an explicit user approval flow that identifies the agent and returns a scoped credential privately, not through a copied token in chat.