feat: add shared API client with auth and error handling

src/services/api-client.ts

@@ -0,0 +1,113 @@
+import axios, { type AxiosRequestConfig } from "axios";
+import { getApiBaseUrl, getApiKey, CHARACTER_LIMIT } from "../constants.js";
+
+/**
+ * Make an authenticated request to the Novu API.
+ *
+ * @param path - API path including version prefix (e.g., "/v1/events/trigger" or "/v2/topics")
+ * @param method - HTTP method
+ * @param data - Request body for POST/PUT/PATCH
+ * @param params - Query parameters for GET requests
+ */
+export async function novuRequest<T>(
+  path: string,
+  method: "GET" | "POST" | "PUT" | "PATCH" | "DELETE" = "GET",
+  data?: unknown,
+  params?: Record<string, unknown>
+): Promise<T> {
+  // Strip undefined values from params to avoid sending "?key=undefined"
+  const cleanParams = params
+    ? Object.fromEntries(
+        Object.entries(params).filter(([, v]) => v !== undefined)
+      )
+    : undefined;
+
+  const config: AxiosRequestConfig = {
+    method,
+    url: `${getApiBaseUrl()}${path}`,
+    data,
+    params: cleanParams,
+    timeout: 30_000,
+    headers: {
+      Authorization: `ApiKey ${getApiKey()}`,
+      "Content-Type": "application/json",
+      Accept: "application/json",
+    },
+  };
+
+  const response = await axios(config);
+  return response.data as T;
+}
+
+/**
+ * Format an API error into an actionable string for the LLM.
+ */
+export function formatApiError(error: unknown): string {
+  if (axios.isAxiosError(error)) {
+    if (error.response) {
+      const status = error.response.status;
+      const body = error.response.data as
+        | { message?: string; error?: string }
+        | undefined;
+      const detail =
+        body?.message || body?.error || JSON.stringify(body);
+
+      switch (status) {
+        case 400:
+          return `Error (400 Bad Request): ${detail}. Check that all required parameters are provided and valid.`;
+        case 401:
+          return "Error (401 Unauthorized): Invalid or missing API key. Set NOVU_SECRET_KEY environment variable with a valid key from https://dashboard.novu.co";
+        case 403:
+          return `Error (403 Forbidden): ${detail}. Check your API key permissions.`;
+        case 404:
+          return `Error (404 Not Found): ${detail}. Verify the resource ID/key is correct.`;
+        case 409:
+          return `Error (409 Conflict): ${detail}. The resource may already exist.`;
+        case 413:
+          return `Error (413 Payload Too Large): ${detail}. Reduce the request body size.`;
+        case 422:
+          return `Error (422 Unprocessable Entity): ${detail}. Check request body schema.`;
+        case 429:
+          return "Error (429 Rate Limited): Too many requests. Wait before retrying. See https://docs.novu.co/api-reference/rate-limiting";
+        default:
+          return `Error (${status}): ${detail}`;
+      }
+    } else if (error.code === "ECONNABORTED") {
+      return "Error: Request timed out after 30s. Try again or check Novu service status.";
+    } else if (error.code === "ENOTFOUND") {
+      return `Error: Cannot reach Novu API at ${getApiBaseUrl()}. Check NOVU_API_URL and network connectivity.`;
+    }
+  }
+  return `Error: ${error instanceof Error ? error.message : String(error)}`;
+}
+
+/**
+ * Truncate a string if it exceeds CHARACTER_LIMIT, appending a truncation notice.
+ */
+export function truncateIfNeeded(text: string): string {
+  if (text.length <= CHARACTER_LIMIT) return text;
+  const truncated = text.slice(0, CHARACTER_LIMIT);
+  return (
+    truncated +
+    "\n\n... [Response truncated. Use pagination or filters to see more results.]"
+  );
+}
+
+/**
+ * Create a standard MCP tool result (success).
+ */
+export function toolResult(text: string) {
+  return {
+    content: [{ type: "text" as const, text: truncateIfNeeded(text) }],
+  };
+}
+
+/**
+ * Create a standard MCP tool result (error).
+ */
+export function toolError(error: unknown) {
+  return {
+    content: [{ type: "text" as const, text: formatApiError(error) }],
+    isError: true,
+  };
+}