# Completions ## Create a Text Completion `$ ant completions create` **post** `/v1/complete` [Legacy] Create a Text Completion. The Text Completions API is a legacy API. We recommend using the [Messages API](https://docs.claude.com/en/api/messages) going forward. Future models and features will not be compatible with Text Completions. See our [migration guide](https://docs.claude.com/en/api/migrating-from-text-completions-to-messages) for guidance in migrating from Text Completions to Messages. ### Parameters - `--max-tokens-to-sample: number` Body param: The maximum number of tokens to generate before stopping. Note that our models may stop _before_ reaching this maximum. This parameter only specifies the absolute maximum number of tokens to generate. - `--model: "claude-opus-4-8" or "claude-opus-4-7" or "claude-mythos-preview" or 15 more or string` Body param: The model that will complete your prompt. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - `--prompt: string` Body param: The prompt that you want Claude to complete. For proper response generation you will need to format your prompt using alternating ` Human:`and` Assistant:` conversational turns. For example: ``` " Human: {userQuestion} Assistant:" ``` See [prompt validation](https://docs.claude.com/en/api/prompt-validation) and our guide to [prompt design](https://docs.claude.com/en/docs/intro-to-prompting) for more details. - `--metadata: optional object { user_id }` Body param: An object describing metadata about the request. - `--stop-sequence: optional array of string` Body param: Sequences that will cause the model to stop generating. Our models stop on `" Human:"`, and may include additional built-in stop sequences in the future. By providing the stop_sequences parameter, you may include additional strings that will cause the model to stop generating. - `--temperature: optional number` Body param: Amount of randomness injected into the response. Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks. Note that even with `temperature` of `0.0`, the results will not be fully deterministic. - `--top-k: optional number` Body param: Only sample from the top K options for each subsequent token. Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277). Recommended for advanced use cases only. - `--top-p: optional number` Body param: Use nucleus sampling. In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`. Recommended for advanced use cases only. - `--beta: optional array of AnthropicBeta` Header param: Optional header to specify the beta version(s) you want to use. ### Returns - `completion: object { id, completion, model, 2 more }` - `id: string` Unique object identifier. The format and length of IDs may change over time. - `completion: string` The resulting completion up to and excluding the stop sequences. - `model: "claude-opus-4-8" or "claude-opus-4-7" or "claude-mythos-preview" or 15 more or string` The model that will complete your prompt. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - `"claude-opus-4-8"` Frontier intelligence for long-running agents and coding - `"claude-opus-4-7"` Frontier intelligence for long-running agents and coding - `"claude-mythos-preview"` New class of intelligence, strongest in coding and cybersecurity - `"claude-opus-4-6"` Frontier intelligence for long-running agents and coding - `"claude-sonnet-4-6"` Best combination of speed and intelligence - `"claude-haiku-4-5"` Fastest model with near-frontier intelligence - `"claude-haiku-4-5-20251001"` Fastest model with near-frontier intelligence - `"claude-opus-4-5"` Premium model combining maximum intelligence with practical performance - `"claude-opus-4-5-20251101"` Premium model combining maximum intelligence with practical performance - `"claude-sonnet-4-5"` High-performance model for agents and coding - `"claude-sonnet-4-5-20250929"` High-performance model for agents and coding - `"claude-opus-4-1"` Exceptional model for specialized complex tasks - `"claude-opus-4-1-20250805"` Exceptional model for specialized complex tasks - `"claude-opus-4-0"` Powerful model for complex tasks - `"claude-opus-4-20250514"` Powerful model for complex tasks - `"claude-sonnet-4-0"` High-performance model with extended thinking - `"claude-sonnet-4-20250514"` High-performance model with extended thinking - `"claude-3-haiku-20240307"` Fast and cost-effective model - `stop_reason: string` The reason that we stopped. This may be one the following values: * `"stop_sequence"`: we reached a stop sequence — either provided by you via the `stop_sequences` parameter, or a stop sequence built into the model * `"max_tokens"`: we exceeded `max_tokens_to_sample` or the model's maximum - `type: "completion"` Object type. For Text Completions, this is always `"completion"`. ### Example ```cli ant completions create \ --api-key my-anthropic-api-key \ --max-tokens-to-sample 256 \ --model claude-opus-4-8 \ --prompt ' Human: Hello, world! Assistant:' ``` #### Response ```json { "id": "compl_018CKm6gsux7P8yMcwZbeCPw", "completion": " Hello! My name is Claude.", "model": "claude-2.1", "stop_reason": "stop_sequence", "type": "completion" } ``` ## Domain Types ### Completion - `completion: object { id, completion, model, 2 more }` - `id: string` Unique object identifier. The format and length of IDs may change over time. - `completion: string` The resulting completion up to and excluding the stop sequences. - `model: "claude-opus-4-8" or "claude-opus-4-7" or "claude-mythos-preview" or 15 more or string` The model that will complete your prompt. See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options. - `"claude-opus-4-8"` Frontier intelligence for long-running agents and coding - `"claude-opus-4-7"` Frontier intelligence for long-running agents and coding - `"claude-mythos-preview"` New class of intelligence, strongest in coding and cybersecurity - `"claude-opus-4-6"` Frontier intelligence for long-running agents and coding - `"claude-sonnet-4-6"` Best combination of speed and intelligence - `"claude-haiku-4-5"` Fastest model with near-frontier intelligence - `"claude-haiku-4-5-20251001"` Fastest model with near-frontier intelligence - `"claude-opus-4-5"` Premium model combining maximum intelligence with practical performance - `"claude-opus-4-5-20251101"` Premium model combining maximum intelligence with practical performance - `"claude-sonnet-4-5"` High-performance model for agents and coding - `"claude-sonnet-4-5-20250929"` High-performance model for agents and coding - `"claude-opus-4-1"` Exceptional model for specialized complex tasks - `"claude-opus-4-1-20250805"` Exceptional model for specialized complex tasks - `"claude-opus-4-0"` Powerful model for complex tasks - `"claude-opus-4-20250514"` Powerful model for complex tasks - `"claude-sonnet-4-0"` High-performance model with extended thinking - `"claude-sonnet-4-20250514"` High-performance model with extended thinking - `"claude-3-haiku-20240307"` Fast and cost-effective model - `stop_reason: string` The reason that we stopped. This may be one the following values: * `"stop_sequence"`: we reached a stop sequence — either provided by you via the `stop_sequences` parameter, or a stop sequence built into the model * `"max_tokens"`: we exceeded `max_tokens_to_sample` or the model's maximum - `type: "completion"` Object type. For Text Completions, this is always `"completion"`.