fix: Normalize paths to prevent double slashes causing 404 errors (#37)

packages/mcp-server/src/features/local-rest-api/index.ts

@@ -251,7 +251,9 @@ export function registerLocalRestApiTools(tools: ToolRegistry, server: Server) {
       "List files in the root directory or a specified subdirectory of your vault.",
     ),
     async ({ arguments: args }) => {
-      const path = args.directory ? `${args.directory}/` : "";
+      // Normalize path by removing trailing slashes to prevent double slashes
+      const directory = args.directory?.replace(/\/+$/, "") || "";
+      const path = directory ? `${directory}/` : "";
       const data = await makeRequest(
         LocalRestAPI.ApiVaultFileResponse.or(
           LocalRestAPI.ApiVaultDirectoryResponse,

packages/mcp-server/src/features/local-rest-api/pathNormalization.test.ts

@@ -0,0 +1,120 @@
+import { describe, expect, test } from "bun:test";
+
+/**
+ * Tests for path normalization logic used in list_vault_files tool
+ * to prevent double slashes when constructing API paths
+ */
+describe("Path normalization for list_vault_files", () => {
+  /**
+   * Helper function that replicates the normalization logic from index.ts
+   * This ensures trailing slashes are removed before constructing the API path
+   */
+  function normalizeDirectoryPath(directory?: string): string {
+    // This replicates the logic from index.ts line 255-256
+    const normalized = directory?.replace(/\/+$/, "") || "";
+    const path = normalized ? `${normalized}/` : "";
+    return path;
+  }
+
+  test("removes single trailing slash from directory", () => {
+    const input = "Documents/";
+    const expected = "Documents/";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("removes multiple trailing slashes from directory", () => {
+    const input = "Documents///";
+    const expected = "Documents/";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles directory without trailing slash", () => {
+    const input = "Documents";
+    const expected = "Documents/";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles empty string directory", () => {
+    const input = "";
+    const expected = "";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles undefined directory", () => {
+    const input = undefined;
+    const expected = "";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles nested paths with trailing slashes", () => {
+    const input = "Documents/Work/Projects/";
+    const expected = "Documents/Work/Projects/";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles nested paths with multiple trailing slashes", () => {
+    const input = "Documents/Work/Projects///";
+    const expected = "Documents/Work/Projects/";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles root directory with single slash", () => {
+    const input = "/";
+    const expected = "";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("handles root directory with multiple slashes", () => {
+    const input = "///";
+    const expected = "";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+
+  test("preserves internal slashes while removing trailing ones", () => {
+    const input = "Documents/Work/Projects/2024/";
+    const expected = "Documents/Work/Projects/2024/";
+    expect(normalizeDirectoryPath(input)).toBe(expected);
+  });
+});
+
+describe("API path construction prevents double slashes", () => {
+  /**
+   * Simulates the full path construction as done in index.ts
+   * to verify no double slashes are created
+   */
+  function constructApiPath(directory?: string): string {
+    const normalized = directory?.replace(/\/+$/, "") || "";
+    const path = normalized ? `${normalized}/` : "";
+    return `/vault/${path}`;
+  }
+
+  test("constructs correct path for directory without trailing slash", () => {
+    expect(constructApiPath("Documents")).toBe("/vault/Documents/");
+  });
+
+  test("constructs correct path for directory with trailing slash", () => {
+    expect(constructApiPath("Documents/")).toBe("/vault/Documents/");
+  });
+
+  test("constructs correct path for directory with multiple trailing slashes", () => {
+    expect(constructApiPath("Documents///")).toBe("/vault/Documents/");
+  });
+
+  test("constructs correct path for root directory", () => {
+    expect(constructApiPath("")).toBe("/vault/");
+    expect(constructApiPath(undefined)).toBe("/vault/");
+  });
+
+  test("constructs correct path for nested directory", () => {
+    expect(constructApiPath("Documents/Work/Projects")).toBe(
+      "/vault/Documents/Work/Projects/",
+    );
+  });
+
+  test("prevents double slashes at vault boundary", () => {
+    // This was the bug: /vault//Documents/
+    const path = constructApiPath("Documents/");
+    expect(path).not.toContain("//");
+    expect(path).toBe("/vault/Documents/");
+  });
+});