thedotmack/claude-mem · error

file_path is required

Error message

file_path is required

What it means

resolveWithinWorkspace resolves a requested file path safely within the workspace root for MCP smart-file-read tools. It throws 'file_path is required' when the filePath argument is missing, not a string, or empty/whitespace-only.

Solutions

1. Supply a non-empty file_path string in the MCP tool call, e.g. file_path: "src/index.ts".
2. Fix the client code so the parameter is actually populated (check for failed interpolation or undefined variables).
3. Validate the argument client-side before invoking: typeof p === 'string' && p.trim().length > 0.

Example fix

// before
await read({ file_path: opts.path ?? '' });
// after
if (!opts.path || !opts.path.trim()) throw new Error('file_path is required');
await read({ file_path: opts.path });

function hasFilePath(args: unknown): args is { file_path: string } {
  return typeof args === 'object' && args !== null &&
    typeof (args as any).file_path === 'string' && (args as any).file_path.trim().length > 0;
}

function isNonEmptyString(v: unknown): v is string {
  return typeof v === 'string' && v.trim().length > 0;
}

try {
  const resolved = await resolveWithinWorkspace(args.file_path);
} catch (err) {
  if (String(err) === 'Error: file_path is required') return mcpError(400, 'file_path parameter is required');
  throw err;
}

When it happens

Trigger: An MCP file tool call passes file_path as empty string, whitespace, null/undefined, or a non-string value (e.g. a number or object) into resolveWithinWorkspace.

Common situations: Client omits the file_path parameter in the tool call; a template variable failed to interpolate and left an empty string; JSON schema on the client side does not enforce the parameter.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• " " is required
• observation_add: "content" is required
• Missing required argument: name
• observation_context: "query" is required
• observation_generation_status: "jobId" is required

AI-assisted analysis of thedotmack/claude-mem@d8bc9755e7 (2026-09-17). Data as JSON: /api/errors/75af9ec2deaf86f3. Report an issue: GitHub.

Appendix: source

Thrown at src/services/smart-file-read/workspace-path.ts:30

/**
 * Resolve a caller-supplied path and refuse anything that escapes the workspace.
 *
 * smart_unfold / smart_outline / smart_search used to `resolve()` the argument
 * with no containment check, so an MCP call could read ~/.ssh/id_rsa (and any
 * other file the OS user can read). path.resolve() is lexical only — it does
 * not follow symlinks — so both sides are realpath'd before the comparison.
 * Missing targets fall back to the lexical path so the caller still gets a
 * natural ENOENT, but only after the lexical path itself is known not to escape.
 *
 * @see thedotmack/claude-mem#3861
 */
export async function resolveWithinWorkspace(
  filePath: string,
  workspaceCwd: string = process.cwd(),
): Promise<string> {
  if (typeof filePath !== 'string' || filePath.trim().length === 0) {
    throw new Error('file_path is required');
  }

  const root = await realpath(resolve(workspaceCwd));
  const lexicallyResolved = resolve(root, expandLeadingTilde(filePath.trim()));
  let resolved: string;
  try {
    resolved = await realpath(lexicallyResolved);
  } catch {
    resolved = lexicallyResolved;
  }

  if (resolved !== root && !resolved.startsWith(root + sep)) {
    throw new Error(
      `Access denied: "${filePath}" resolves outside the workspace (${root}). ` +
      'MCP file tools can only read files within the current project.',
    );
  }

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