[BUG] Empty settingSources array causes --setting-sources "" to consume next CLI flag

[nick-inkeep]

Bug Description

When settingSources is not explicitly provided to query(), the SDK passes --setting-sources "" (empty string) to the Claude Code CLI. The CLI argument parser then consumes the next flag (--permission-mode) as the setting source value, producing:

Error processing --setting-sources: Invalid setting source: --permission-mode. Valid options are: user, project, local

This blocks all default usage of the SDK — any query() call without explicit settingSources fails.

Version

@anthropic-ai/claude-agent-sdk@0.2.84, Claude Code CLI 2.1.84

Reproduction

import { query } from '@anthropic-ai/claude-agent-sdk';

// Simplest possible call — no settingSources configured
for await (const msg of query('Say hello')) {
  console.log(msg.type);
}
// → Error: Invalid setting source: --permission-mode

Expected Behavior

When settingSources is not provided, the SDK should not pass --setting-sources to the CLI at all — matching the behavior of other array-typed flags like --betas, --allowedTools, and --disallowedTools, which are correctly omitted when their arrays are empty.

Workaround

for await (const msg of query('Say hello', { settingSources: ['user'] })) {
  console.log(msg.type);
}

Explicitly providing a non-empty settingSources avoids the empty-string argument.

Additional Context

• The client() constructor appears to have the same issue (hardcoded empty settingSources array)

[ElliotJLT]

The fix is a one-liner in the CLI argument builder. In the compiled sdk.mjs, the current check is:

if(h) p.push("--setting-sources", h.join(","))

Arrays are truthy in JS, so an empty [] still emits --setting-sources "", which consumes the next flag. The fix:

if(h && h.length > 0) p.push("--setting-sources", h.join(","))

This matches the existing pattern used by --betas (if(J&&J.length>0)), --allowedTools (if(B$.length>0)), and --disallowedTools (if(x$.length>0)).

Since this repo only contains published artifacts, this would need to be applied to the TypeScript source internally.