> ## Documentation Index > Fetch the complete documentation index at: https://mux-mike-promote-experiments.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Models > Select and configure AI models in Xum Xum supports multiple AI providers. Configure provider API keys in **Settings → Providers** — see [Providers](/config/providers) for setup. ## First-class Models Xum ships with curated models kept up to date with the frontier. Use any custom model with `/model `. | Model | ID | Aliases | Default | | - | - | - | - | | Fable 5.1 | anthropic:claude-fable-5-1 | `fable` | | | Mythos 5.1 | anthropic:claude-mythos-5-1 | `mythos` | | | Opus 5.5 | anthropic:claude-opus-5-5 | `opus` | ✓ | | Sonnet 5.5 | anthropic:claude-sonnet-5-5 | `sonnet` | | | Haiku 4.5 | anthropic:claude-haiku-4-5 | `haiku` | | | GPT-6.1 Sol | openai:gpt-6.1-sol | `gpt`, `sol` | | | GPT-6 Luna | openai:gpt-6-luna | `luna` | | | GPT-6 Astra | openai:gpt-6-astra | `astra`, `gpt-6-astra` | | | Daybreak Blue Latest | openai:daybreak-blue-latest | — | | | Daybreak Red Latest | openai:daybreak-red-latest | — | | | Gemini 3.1 Pro Preview | google:gemini-3.1-pro-preview | `gemini`, `gemini-pro` | | | Gemini 3.8 Flash | google:gemini-3.8-flash | `gemini-flash` | | | Grok 4.7 | xai:grok-4.7 | `grok`, `grok-4.7` | | | DeepSeek V4 Pro | deepseek:deepseek-v4-pro | `deepseek`, `deepseek-pro`, `deepseek-v4`, `deepseek-v4-pro` | | | DeepSeek V4 Flash | deepseek:deepseek-v4-flash | `deepseek-flash`, `deepseek-v4-flash` | | | Kimi K3 | moonshotai:kimi-k3 | `kimi`, `k3`, `kimi-k3` | | | GLM 5.3 Flash | zai:glm-5.3-flash | `glm`, `glm-flash`, `glm-5.3-flash` | | Xum supports the GPT-6 tiers (GPT-6.1 Sol, GPT-6 Astra, and GPT-6 Luna); older OpenAI GPT models are no longer supported. GPT-6 Luna supports thinking from off through max on the default Responses API route. On the opt-in Chat Completions route, Xum disables its reasoning because OpenAI only supports function calling there with reasoning off. GPT-6.1 Sol (the `gpt` and `sol` aliases) and GPT-6 Astra support thinking from low through max; OpenAI does not allow turning their reasoning off. Use the default Responses API route with them, because OpenAI does not support tool calling for these models on Chat Completions. ### OpenAI Ultrafast To use OpenAI's fastest processing tier, choose **ultrafast** as the service tier in **Settings → Providers → OpenAI**. Xum sends it only to models that OpenAI serves Ultrafast for: GPT-6 Astra. Other models run without a service tier instead of falling back to Fast. Ultrafast costs 6× the Standard price, and Xum's cost tracking uses that rate. OpenAI says GPT-6.1 Sol Ultrafast will arrive later. ### Pro reasoning mode (GPT-6) GPT-6.1 Sol, GPT-6 Astra, and GPT-6 Luna support OpenAI's pro reasoning mode. Open the reasoning selector next to the model picker and enable **Pro mode** (or run "Toggle Pro Reasoning Mode" from the Command Palette) to send `reasoning.mode: "pro"` with each request. The setting is saved per workspace. Pro mode can consume more tokens and responses can take noticeably longer. Pro is available on supported direct OpenAI Responses API routes. Gateway routes, Chat Completions, and Codex OAuth use standard mode. For advisor calls, use the **Reasoning** picker in the **Advisor** section of **Settings → Agents**. Advisor Pro mode is saved independently of reasoning effort and the calling chat’s mode. ## Model Selection Keyboard shortcuts: * **Cycle models** * **macOS:** `Cmd+/` * **Windows/Linux:** `Ctrl+/` To *choose* a specific model, click the model pill in the chat footer. Alternatively, use the Command Palette (`Cmd+Shift+P` / `Ctrl+Shift+P`): 1. Type "model" 2. Select "Change Model" 3. Choose from available models Models are specified in the format: `provider:model-name` ## Add custom models Under **Settings → Models**, choose a provider and use the **Model ID** field to search its catalog or enter an ID. Clicking a suggestion, or selecting one with arrow keys and Enter, adds it immediately. Without an explicit selection, **Add** or Enter adds the ID you typed. Opening the field requests suggestions for the selected provider. Discovery does not add models to your configured list or change routing. You can still enter IDs while suggestions load, when the catalog is empty, or when listing fails. ### Suggestion availability | Provider | Catalog used for suggestions | | - | - | | Anthropic, xAI, DeepSeek, Moonshot AI, OpenRouter | The configured provider's model-list API. | | OpenAI | The API-key catalog. Codex OAuth-only listing and Azure deployment enumeration are not supported. If both an API key and OAuth are configured, suggestions describe the API-key account, not OAuth access. | | Google | Gemini Developer API models that advertise content generation. Vertex AI is not included. | | Ollama | Models installed on the configured Ollama server. | | GitHub Copilot | The configured endpoint's catalog, using the existing token without updating Copilot's login catalog. | | Coder | The existing deployment catalog. Use **Settings → Providers → Coder → Refresh models** to update it. | | Z.ai and custom providers | Available only if the configured server supports model listing. Supporting inference alone does not guarantee a listing API. This applies to OpenAI-compatible, OpenAI Responses, and Anthropic Messages custom providers. | | Bedrock | On-demand text foundation models and active inference profiles backed only by text models, in the configured region. Listing requires a supported fixed credential configuration and permission for both catalog operations. | Bedrock suggestions support configured or environment bearer tokens, explicit AWS keys, and environment AWS keys when no profile is selected. They use standard regional endpoints. Profile-based authentication, SSO, role assumption, credential processes, metadata credentials, and custom endpoints are not supported for suggestions; enter model IDs manually for those configurations. These limits apply to discovery, not to inference. Xum Gateway remains a routing option, not a provider in this field. Configure it through the **Route** column instead. A catalog entry does not guarantee account access, tool support, or availability through every route. Adding a model is separate from choosing its route; see [Providers](/config/providers) for routing and credential setup. ## Model fallbacks When a model refuses to respond, Xum can retry the turn on the next model in that model's fallback chain. Chains apply only to refusals, never to quota, auth, or network errors. Edit them under **Settings → Models → Model Fallbacks**, or in `~/.xum/config.json` under `modelFallbacks`. New installs start with these chains: | Model | Falls back to | | - | - | | `anthropic:claude-fable-5-1` | `anthropic:claude-opus-5` | | `anthropic:claude-sonnet-5-5` | `anthropic:claude-sonnet-5` | Claude Sonnet 5.5 can refuse some higher-risk cybersecurity requests, and Anthropic's own fallback for those requests is Claude Sonnet 5. Updates never change an existing config's chains. If your config predates the Sonnet 5.5 chain, add it by hand: 1. Under **Settings → Models**, add the custom model `claude-sonnet-5` for Anthropic. 2. Under **Model Fallbacks**, add a chain for `anthropic:claude-sonnet-5-5` and pick `anthropic:claude-sonnet-5`. Or add the entry to `~/.xum/config.json` directly: ```json theme={null} { "modelFallbacks": { "anthropic:claude-sonnet-5-5": { "models": ["anthropic:claude-sonnet-5"] } } } ``` ## One-shot Overrides Override the model or thinking level for a single message using slash commands. The override applies only to that message — workspace settings stay unchanged. ### Syntax | Command | Effect | | - | - | | `/sonnet explain this code` | Use Sonnet for one message | | `/opus+high deep review` | Use Opus with high thinking | | `/haiku+0 quick answer` | Use Haiku at its lowest thinking level | | `/+2 analyze this` | Keep current model, set thinking level 2 | ### Thinking levels Append `+level` to any model alias. Levels can be **named** (`off`, `low`, `medium`/`med`, `high`, `max`) or **numeric** (`0`–`9`). Numeric levels are **model-relative** — they map to the model's allowed thinking range: * `0` = model's lowest allowed level (e.g., `off` for Haiku and Sonnet, `low` for Opus or Astra) * Higher numbers select progressively higher levels, clamped to the model's maximum This means `/haiku+0` disables thinking while `/astra+0` sets thinking to low (Astra's minimum). Use `/+level` (no model) to override thinking on the current model: `/+0 quick answer` ### CLI The `xum run` CLI accepts the same thinking levels via `--thinking`: ```bash theme={null} xum run -t 0 "Quick fix" # Lowest thinking for the model xum run -t high "Deep analysis" # Named level ``` ## Next Steps Set up API keys for Anthropic, OpenAI, Google, and other providers.