mirror of
https://github.com/MBombeck/HealthLog.git
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Marc-André Bombeck
d947bb1104
Introduce a read-only Model Context Protocol surface built on the official
@modelcontextprotocol/sdk so a user can query their own HealthLog data from an
MCP-capable assistant over local stdio with a pasted, scoped Bearer token — no
extra infrastructure.
The tool and resource layer in src/lib/mcp is transport-agnostic: five read
tools — list_metrics, get_metric_series, get_medication_compliance, get_labs,
get_correlations — each a thin wrapper over the existing server-authoritative
retrieval paths, returning structured values, units, reference bands, and
provenance with an explicit { present: false } for absence and no prose
verdicts. Two resources expose the user's profile (data-minimised) and
medication list. A stdio entrypoint (src/cli/mcp-stdio.ts, pnpm mcp:stdio)
resolves the token through the shared Bearer path and binds the session to
<user>:<token>; with no token it refuses to start.
Read-only and admin-unreachable by construction: only read tools are
registered, and requireAdmin stays cookie-only so the Bearer/MCP wire can never
elevate. Covered by unit tests for every tool and resource, the auth/scope
model, and the cookie-only admin boundary. The server ships in the existing
container; docker compose up is unchanged.
66 lines
2.1 KiB
TypeScript
66 lines
2.1 KiB
TypeScript
/**
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* Local stdio entrypoint for the HealthLog MCP server.
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*
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* A power-user runs this in a plain Node process and points an MCP client
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* (Claude Desktop, etc.) at it. Authentication is a pasted, scoped `hlk_<hex>`
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* Bearer token — no OAuth infrastructure (REQ-T1). The token is read from the
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* `HEALTHLOG_MCP_TOKEN` environment variable (preferred — keeps the secret out
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* of the process argument list) or, as a fallback, the first CLI argument.
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*
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* Off by default: with no token the server refuses to start. Running it with a
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* minted token IS the opt-in.
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*
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* Run it with tsx (the standalone production image strips tsx, so this is a
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* local-only tool):
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*
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* HEALTHLOG_MCP_TOKEN=hlk_... \
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* API_TOKEN_HMAC_KEY=... DATABASE_URL=... ENCRYPTION_KEYS=... \
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* pnpm dlx tsx src/cli/mcp-stdio.ts
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*
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* stdout is the JSON-RPC channel — every diagnostic goes to stderr so it can
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* never corrupt the protocol stream.
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*/
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import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
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import { createMcpServer } from "@/lib/mcp/server";
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import { resolveMcpAuthContext } from "@/lib/mcp/auth";
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function readToken(): string | null {
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const fromEnv = process.env.HEALTHLOG_MCP_TOKEN?.trim();
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if (fromEnv) return fromEnv;
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const fromArg = process.argv[2]?.trim();
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if (fromArg) return fromArg;
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return null;
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}
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async function main(): Promise<void> {
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const token = readToken();
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if (!token) {
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console.error(
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"HealthLog MCP: no token. Set HEALTHLOG_MCP_TOKEN (a scoped hlk_ Bearer token) or pass it as the first argument.",
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);
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process.exit(1);
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}
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let ctx;
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try {
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ctx = await resolveMcpAuthContext(token);
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} catch {
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// Do not echo the token or the underlying reason to stderr.
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console.error("HealthLog MCP: token rejected.");
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process.exit(1);
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}
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const server = createMcpServer(ctx);
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const transport = new StdioServerTransport();
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await server.connect(transport);
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console.error(
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`HealthLog MCP server running on stdio (session ${ctx.binding}).`,
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);
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}
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main().catch((error) => {
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console.error("HealthLog MCP: fatal error during startup.", error);
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process.exit(1);
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});
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