openevidence-sdk-patterns

# OpenEvidence SDK Patterns ## Overview Production-ready patterns for the OpenEvidence clinical evidence API. OpenEvidence provides REST endpoints for querying medical literature, retrieving clinical guidelines, and generating evidence-based recommendations. The API authenticates via `OPENEVIDENCE_API_KEY` and returns structured clinical data with citation provenance. A singleton client enforces consistent auth, handles healthcare-specific errors, and preserves citation chains for audit compliance. ## Singleton Client ```typescript const OE_BASE = 'https://api.openevidence.com/v1'; let _client: OpenEvidenceClient | null = null; export function getClient(): OpenEvidenceClient { if (!_client) { const apiKey = process.env.OPENEVIDENCE_API_KEY; if (!apiKey) throw new Error('OPENEVIDENCE_API_KEY must be set — get it from openevidence.com/developer'); _client = new OpenEvidenceClient(apiKey); } return _client; } class OpenEvidenceClient { private headers: Record<string, string>; constructor(apiKey: string) { this.headers = { 'Authorization': `Bearer ${apiKey}`, 'Content-Type': 'application/json' }; } async query(question: string, opts: { specialty?: string; maxResults?: number } = {}): Promise<EvidenceResponse> { const res = await fetch(`${OE_BASE}/query`, { method: 'POST', headers: this.headers, body: JSON.stringify({ question, specialty: opts.specialty, max_results: opts.maxResults ?? 10 }) }); if (!res.ok) throw new OEError(res.status, awa...