Cursor Compatibility

Cursor has restricted third-party API providers

Recent Cursor releases tightly limit custom API providers. Connecting through Flatrouter currently hits these incompatibilities:

• Inline (Tab) completion does not work at all — Tab completion is locked to Cursor's official models and cannot be swapped
• Agent mode is unavailable — Background Agent does not support third-party API providers
• Auto model selection breaks custom config — Auto mode bypasses your settings and falls back to official models
• Cursor Pro paywall — even when the config looks right, the free plan cannot use custom models

Taken together, Cursor is not a good way to reach Flatrouter today.

Recommended alternatives

These tools have full Flatrouter support with no feature lockouts:

• Claude Code — AI coding agent, fully supported
• Codex CLI — OpenAI's official CLI, fully supported
• Zed Editor — code editor, fully supported
• Cherry Studio — desktop client, fully supported

Keep using the Cursor editor

If you like Cursor's editing experience and do not want to switch editors, run Claude Code or Codex CLI in Cursor's built-in terminal. The editor stays Cursor; the AI traffic goes through Flatrouter. The two do not interfere.

Open the built-in terminal (Ctrl+`) and use them as usual:

# Claude Code
claude "refactor this function"

# Codex CLI
codex "refactor this function"

Claude Code and Codex CLI read the current directory and finish the coding task in the terminal. Files you have open in Cursor stay in sync.

Why Cursor does not work

Inline completion is locked

Tab completion (inline completion) is one of Cursor's core features, but it is hard-coded to Cursor's official models and never reads a custom API config. Even with a correct Flatrouter base URL and API key, Tab completion still goes through Cursor's official channel.

Agent mode does not support third parties

Background Agent is bound to Cursor's official API. Third-party providers cannot plug in.

Auto mode overrides custom config

Cursor's Auto mode picks the "best" model, but that logic prefers official models and skips the custom base URL you entered.

The free plan cannot use custom models

Even with Cursor Pro, support for custom API providers keeps getting tighter. Cursor's business depends on official-model usage; third-party access is not a design goal.