Codex

model = "MiniMax-M3.1-Flash"
model_provider = "minimax"
model_context_window = 524288
preferred_auth_method = "apikey"
forced_login_method = "api"

[model_providers.minimax]
name = "MiniMax"
base_url = "https://api.minimax.io/v1"
experimental_bearer_token = "<MINIMAX_API_KEY>"
wire_api = "responses"

Configure model capabilities (optional)

model_catalog_json = "~/.codex/model-catalogs/custom-catalog.json"

{
  "models": [
    {
      "slug": "MiniMax-M3.1-Flash",
      "display_name": "MiniMax-M3.1-Flash",
      "description": "MiniMax M3.1 Flash",
      "default_reasoning_level": "max",
      "supported_reasoning_levels": [
        { "effort": "low", "description": "Low" },
        { "effort": "medium", "description": "Medium" },
        { "effort": "high", "description": "High" },
        { "effort": "xhigh", "description": "Extra high" },
        { "effort": "max", "description": "Maximum" }
      ],
      "shell_type": "shell_command",
      "visibility": "list",
      "supported_in_api": true,
      "priority": 0,
      "base_instructions": "You are Codex, a coding agent based on MiniMax-M3.1-Flash. You and the user share the same workspace and collaborate to achieve the user's goals.",
      "supports_reasoning_summaries": true,
      "default_reasoning_summary": "none",
      "support_verbosity": false,
      "truncation_policy": { "mode": "tokens", "limit": 10000 },
      "supports_parallel_tool_calls": true,
      "experimental_supported_tools": [],
      "prefer_websockets": false,
      "apply_patch_tool_type": "freeform",
      "web_search_tool_type": "text",
      "supports_image_detail_original": false,
      "tool_mode": "code_mode_only",
      "multi_agent_version": "v2",
      "use_responses_lite": false,
      "input_modalities": ["text", "image"],
      "context_window": 524288,
      "max_context_window": 524288,
      "effective_context_window_percent": 95,
      "auto_compact_token_limit": null,
      "reasoning_summary_format": "experimental",
      "supports_search_tool": true
    }
  ]
}

• slug / display_name: The model identifier and display name used in Codex config and the /model list. Keep this aligned with the model name used by the API.
• default_reasoning_level: The default reasoning effort. MiniMax-M3.1-Flash uses max by default.
• supported_reasoning_levels: Reasoning options users can switch between in /model. MiniMax-M3.1-Flash supports low, medium, high, xhigh, and max; none is not supported.
• base_instructions: Base system prompt Codex adds when using this model. Use it to describe the model identity and collaboration style.
• supports_reasoning_summaries: Enables Codex’s Responses API reasoning path for this model. Set this to true so Codex sends reasoning.effort; otherwise Codex omits the reasoning field even when default_reasoning_level is configured. In this example, default_reasoning_summary is set to none so Codex does not request a separate reasoning summary.
• shell_type: Declares the shell tool-call type supported by the model. This example uses shell_command.
• visibility / supported_in_api / priority: Control whether the model appears in the list, whether it is available through the API, and its ordering priority in the model list.
• supports_parallel_tool_calls: Indicates that the model supports parallel tool calls, allowing Codex to handle multiple tool requests.
• experimental_supported_tools: Reserved list for experimental tool capabilities. Leave it as an empty array when no extra tools are needed.
• input_modalities: Supported input modalities. ["text", "image"] means text and image input are supported.
• truncation_policy: Controls content truncation; this example counts tokens.
• context_window / max_context_window: Set the client context window to the recommended 512K (524,288 tokens) in this example. See the 512K guidance.
• effective_context_window_percent / auto_compact_token_limit: Use 95% of the window as the effective context budget without a separate fixed auto-compaction threshold.

Context window and cost optimization (optional)

Why consider 512K?