Model quality evolves quickly, and we tune the CLI defaults as the ecosystem shifts. Use this guide as a snapshot of how the major options compare today, and expect to revisit it as we publish updates. This guide was last updated on Thursday, December 4th 2025.
1 · Current stack rank (December 2025)
| Rank | Model | Why we reach for it |
|---|
| 1 | Claude Opus 4.5 (default) | Highest quality-and-safety balance; current CLI default for both TUI and exec. |
| 2 | GPT-5.1-Codex-Max | Fast coding loops with support up to Extra High reasoning; great for heavy implementation and debugging. |
| 3 | Claude Sonnet 4.5 | Strong daily driver with balanced cost/quality; great general-purpose choice when you don’t need Opus-level depth. |
| 4 | GPT-5.1-Codex | Quick iteration with solid code quality at lower cost; bump reasoning when you need more depth. |
| 5 | GPT-5.1 | Good generalist, especially when you want OpenAI ergonomics with flexible reasoning effort. |
| 6 | Claude Haiku 4.5 | Fast, cost-efficient for routine tasks and high-volume automation. |
| 7 | Gemini 3 Pro | Strong at mixed reasoning with Low/High settings; helpful for researchy flows with structured outputs. |
| 8 | Gemini 3 Flash | Fast, cheap (0.2× multiplier) with full reasoning support; great for high-volume tasks where speed matters. |
| 9 | Droid Core (GLM-4.6) | Open-source, 0.25× multiplier, great for bulk automation or air-gapped environments; note: no image support. |
We ship model updates regularly. When a new release overtakes the list above,
we update this page and the CLI defaults.
2 · Match the model to the job
| Scenario | Recommended model |
|---|
| Deep planning, architecture reviews, ambiguous product specs | Start with Opus 4.5 (default) for depth and safety. Use Sonnet 4.5 when you want balanced cost/quality, or Codex/Codex-Max for faster iteration with reasoning. |
| Full-feature development, large refactors | Opus 4.5 for default depth and safety. GPT-5.1-Codex-Max when you need speed plus Extra High reasoning; Sonnet 4.5 for balanced loops. |
| Repeatable edits, summarization, boilerplate generation | Haiku 4.5 or Droid Core for speed and cost. GPT-5.1 / GPT-5.1-Codex when you need higher quality or structured outputs. |
| CI/CD or automation loops | Favor Haiku 4.5 or Droid Core for predictable, low-cost throughput. Use Codex or Codex-Max when automation needs stronger reasoning. |
| High-volume automation, frequent quick turns | Haiku 4.5 for speedy feedback. Droid Core when cost is critical or you need air-gapped deployment. |
Claude Opus 4.5 is the top-tier option for extremely complex architecture decisions or critical work where you need maximum reasoning capability. Most tasks don’t require Opus-level power—start with Sonnet 4.5 and escalate only if needed.
/model or by toggling in the settings panel (Shift+Tab → Settings).
3 · Switching models mid-session
- Use
/model (or Shift+Tab → Settings → Model) to swap without losing your chat history.
- If you change providers (e.g. Anthropic to OpenAI), the CLI converts the session transcript between Anthropic and OpenAI formats. The translation is lossy—provider-specific metadata is dropped—but we have not seen accuracy regressions in practice.
- For the best context continuity, switch models at natural milestones: after a commit, once a PR lands, or when you abandon a failed approach and reset the plan.
- If you flip back and forth rapidly, expect the assistant to spend a turn re-grounding itself; consider summarizing recent progress when you switch.
4 · Reasoning effort settings
- Opus / Sonnet / Haiku: Off / Low / Medium / High (default: Off)
- GPT-5.1: None / Low / Medium / High (default: None)
- GPT-5.1-Codex: Low / Medium / High (default: Medium)
- GPT-5.1-Codex-Max: Low / Medium / High / Extra High (default: Medium)
- GPT-5.2: Low / Medium / High (default: Low)
- Gemini 3 Pro: Low / High (default: High)
- Gemini 3 Flash: Minimal / Low / Medium / High (default: High)
- Droid Core (GLM-4.6): None only (default: None; no image support)
Reasoning effort increases latency and cost—start low for simple work and escalate as needed. Extra High is only available on GPT-5.1-Codex-Max.
Change reasoning effort from /model → Reasoning effort, or via the
settings menu.
5 · Bring Your Own Keys (BYOK)
Factory ships with managed Anthropic and OpenAI access. If you prefer to run against your own accounts, BYOK is opt-in—see Bring Your Own Keys for setup steps, supported providers, and billing notes.
Open-source models
Droid Core (GLM-4.6) is an open-source alternative available in the CLI. It’s useful for:
- Air-gapped environments where external API calls aren’t allowed
- Cost-sensitive projects needing unlimited local inference
- Privacy requirements where code cannot leave your infrastructure
- Experimentation with open-source model capabilities
Note: GLM-4.6 does not support image attachments. For image-based workflows, use Claude or GPT models.
To use open-source models, you’ll need to configure them via BYOK with a local inference server (like Ollama) or a hosted provider. See BYOK documentation for setup instructions.
6 · Keep notes on what works
- Track high-impact workflows (e.g., spec generation vs. quick edits) and which combinations of model + reasoning effort feel best.
- Ping the community or your Factory contact when you notice a model regression so we can benchmark and update this guidance quickly.
