diff --git a/src/connectors/io.ts b/src/connectors/io.ts
index e02d13cc..ab1ba52f 100644
--- a/src/connectors/io.ts
+++ b/src/connectors/io.ts
@@ -13,21 +13,43 @@ export async function readConnectorConfig<T extends object>(
   defaultConfig: T,
 ): Promise<T> {
   await ensureConnectorHome(connectorId);
+  const configPath = getConnectorConfigPath(connectorId);
+
+  let rawConfig: string;
 
   try {
-    return {
-      ...defaultConfig,
-      ...(JSON.parse(
-        await readFile(getConnectorConfigPath(connectorId), "utf8"),
-      ) as T),
-    };
+    rawConfig = await readFile(configPath, "utf8");
   } catch (error) {
     if (isFileNotFoundError(error)) {
       return defaultConfig;
     }
 
-    throw error;
+    throw new Error(
+      `Failed to read connector config for ${connectorId} at ${configPath}: ${getErrorMessage(error)}`,
+      { cause: error },
+    );
+  }
+
+  let parsedConfig: unknown;
+  try {
+    parsedConfig = JSON.parse(rawConfig);
+  } catch (error) {
+    throw new Error(
+      `Invalid JSON in connector config for ${connectorId} at ${configPath}: ${getErrorMessage(error)}`,
+      { cause: error },
+    );
+  }
+
+  if (!isJsonObject(parsedConfig)) {
+    throw new Error(
+      `Invalid connector config for ${connectorId} at ${configPath}: expected a JSON object.`,
+    );
   }
+
+  return {
+    ...defaultConfig,
+    ...parsedConfig,
+  };
 }
 
 export async function readConnectorState(
@@ -106,3 +128,11 @@ function isFileNotFoundError(error: unknown): boolean {
     (error as NodeJS.ErrnoException).code === "ENOENT"
   );
 }
+
+function getErrorMessage(error: unknown): string {
+  return error instanceof Error ? error.message : String(error);
+}
+
+function isJsonObject(value: unknown): value is Record<string, unknown> {
+  return typeof value === "object" && value !== null && !Array.isArray(value);
+}
diff --git a/test/connector-config.test.ts b/test/connector-config.test.ts
index 1fdacd2a..a3778fe6 100644
--- a/test/connector-config.test.ts
+++ b/test/connector-config.test.ts
@@ -1,5 +1,137 @@
-import { describe, expect, test } from "vitest";
+import { mkdir, mkdtemp, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import path from "node:path";
+import { afterEach, describe, expect, test, vi } from "vitest";
 import { normalizeStringArray } from "../src/connectors/config.ts";
+import type { ConnectorId } from "../src/connectors/types.ts";
+
+const originalHome = process.env.HOME;
+const originalUserProfile = process.env.USERPROFILE;
+const tempHomes: string[] = [];
+
+afterEach(async () => {
+  vi.resetModules();
+
+  if (originalHome === undefined) {
+    delete process.env.HOME;
+  } else {
+    process.env.HOME = originalHome;
+  }
+  if (originalUserProfile === undefined) {
+    delete process.env.USERPROFILE;
+  } else {
+    process.env.USERPROFILE = originalUserProfile;
+  }
+
+  await Promise.all(
+    tempHomes
+      .splice(0)
+      .map((home) => rm(home, { force: true, recursive: true })),
+  );
+});
+
+async function createTempHome(): Promise<string> {
+  const home = await mkdtemp(path.join(tmpdir(), "openwiki-connector-config-"));
+  tempHomes.push(home);
+  return home;
+}
+
+async function writeConnectorConfigRaw(
+  home: string,
+  connectorId: ConnectorId,
+  contents: string,
+): Promise<string> {
+  const configPath = getTestConnectorConfigPath(home, connectorId);
+  await mkdir(path.dirname(configPath), { recursive: true });
+  await writeFile(configPath, contents, "utf8");
+
+  return configPath;
+}
+
+function getTestConnectorConfigPath(
+  home: string,
+  connectorId: ConnectorId,
+): string {
+  return path.join(home, ".openwiki", "connectors", connectorId, "config.json");
+}
+
+async function loadConnectorIo(home: string) {
+  vi.resetModules();
+  process.env.HOME = home;
+  process.env.USERPROFILE = home;
+
+  return import("../src/connectors/io.ts");
+}
+
+describe("readConnectorConfig", () => {
+  test("returns the default config when the config file is missing", async () => {
+    const home = await createTempHome();
+    const { readConnectorConfig } = await loadConnectorIo(home);
+
+    await expect(
+      readConnectorConfig("google", {
+        enabled: false,
+        format: "metadata",
+        maxMessages: 10,
+      }),
+    ).resolves.toEqual({
+      enabled: false,
+      format: "metadata",
+      maxMessages: 10,
+    });
+  });
+
+  test("merges a valid object config over defaults", async () => {
+    const home = await createTempHome();
+    await writeConnectorConfigRaw(
+      home,
+      "google",
+      `${JSON.stringify({ enabled: true, maxMessages: 5 }, null, 2)}\n`,
+    );
+    const { readConnectorConfig } = await loadConnectorIo(home);
+
+    await expect(
+      readConnectorConfig("google", {
+        enabled: false,
+        format: "metadata",
+        maxMessages: 10,
+      }),
+    ).resolves.toEqual({
+      enabled: true,
+      format: "metadata",
+      maxMessages: 5,
+    });
+  });
+
+  test("adds connector and path context for invalid JSON", async () => {
+    const home = await createTempHome();
+    const configPath = await writeConnectorConfigRaw(home, "slack", "{");
+    const { readConnectorConfig } = await loadConnectorIo(home);
+
+    await expect(
+      readConnectorConfig("slack", { enabled: false }),
+    ).rejects.toThrow("Invalid JSON in connector config for slack");
+    await expect(
+      readConnectorConfig("slack", { enabled: false }),
+    ).rejects.toThrow(configPath);
+  });
+
+  test.each([
+    ["null", "null"],
+    ["array", "[]"],
+    ["boolean", "true"],
+    ["number", "42"],
+    ["string", JSON.stringify("enabled")],
+  ])("rejects %s JSON config values", async (_label, contents) => {
+    const home = await createTempHome();
+    const configPath = await writeConnectorConfigRaw(home, "x", contents);
+    const { readConnectorConfig } = await loadConnectorIo(home);
+
+    await expect(readConnectorConfig("x", { enabled: false })).rejects.toThrow(
+      `Invalid connector config for x at ${configPath}: expected a JSON object.`,
+    );
+  });
+});
 
 describe("normalizeStringArray", () => {
   test("keeps non-empty strings and trims each", () => {