Anthropic Tightens Controls Blocking Third-Party Claude Code Access

Anthropic rolled out technical controls this week to prevent third-party applications from impersonating its Claude Code client, aiming to stop cheaper access and higher usage limits. The changes disrupted workflows for open-source coding agents like OpenCode and curtailed access from competing labs such as xAI using the Cursor IDE, the company publicly clarified on Friday. Some accounts were briefly banned by abuse detection, which Anthropic says it is reversing.