> ## Documentation Index > Fetch the complete documentation index at: https://phaseo.app/docs/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Phaseo Gateway base URL: https://api.phaseo.app/v1. Send `Authorization: Bearer $PHASEO_API_KEY` with every request. > Model IDs look like `provider/model`, for example `openai/gpt-6-astra`. Do not guess IDs: list them with `GET /v1/models` or check https://phaseo.app/models. `phaseo/free` routes to an available free model and needs no wallet balance. > For new text integrations prefer `POST /v1/responses`. `POST /v1/chat/completions` (OpenAI format) and `POST /v1/messages` (Anthropic format) suit existing code. > The full API contract is https://phaseo.app/docs/openapi/v1/openapi.yaml. Official SDKs: `@phaseo/sdk` (TypeScript) and `phaseo` (Python), plus Go, C#, PHP, Ruby and Rust. > Search these docs over MCP at https://phaseo.app/docs/mcp, and install Phaseo skills with `npx skills add https://phaseo.app/docs`. If a page is wrong or out of date, report it with the MCP `submit_feedback` tool. > Manage Phaseo accounts with the `phaseo` CLI (`npm install -g @phaseo/cli`, then `phaseo login` or `phaseo login --device-code`), the `/v1` Management API or the MCP server at `https://mcp.phaseo.app/mcp?access=manage`. Do not send users to the dashboard for account tasks. A person is still needed for sign-up, approving a sign-in, paying the first top-up on the checkout link that `phaseo credits add` returns when no card is saved, confirming each saved-card top-up from the emailed link, and account security (password, MFA, passkeys). Create API keys with `phaseo keys create --name --json`; never guess one. Credit top-ups need `phaseo login --scopes billing:write` first. Task map: https://phaseo.app/docs/v1/developers/manage-from-an-agent.md. # Chat completions > Call /chat/completions from any Phaseo SDK. Call the SDK's chat method to send `POST /v1/chat/completions` and get one completed response. For new integrations, the [Responses API](https://phaseo.app/docs/v1/sdk-reference/client/responses.md) gives one request shape for text, multimodal input, tools and richer output items. ```typescript TypeScript theme={null} const chat = await client.generateText({ model: "openai/gpt-6-astra", messages: [ { role: "system", content: "You are helpful." }, { role: "user", content: "Write a limerick about lighthouses." }, ], }); console.log(chat.choices[0].message.content); ``` ```python Python theme={null} chat = client.generate_text({ "model": "openai/gpt-6-astra", "messages": [ {"role": "system", "content": "You are helpful."}, {"role": "user", "content": "Write a limerick about lighthouses."}, ], }) print(chat["choices"][0]["message"]["content"]) ``` ```go Go theme={null} import ( "context" "fmt" phaseo "github.com/phaseoteam/Phaseo/packages/sdk/sdk-go/v3" ) client, err := phaseo.NewFromEnv() if err != nil { panic(err) } resp, err := client.GenerateText(context.Background(), phaseo.ChatCompletionsRequest{ Model: "openai/gpt-6-astra", Messages: []map[string]interface{}{ {"role": "user", "content": "Write a one-line haiku."}, }, }) if err != nil { panic(err) } fmt.Println(resp["choices"]) ``` ```csharp C# theme={null} using PhaseoSdk; var client = new Phaseo(); var response = await client.GenerateText(new Dictionary { ["model"] = "openai/gpt-6-astra", ["messages"] = new[] { new Dictionary { ["role"] = "user", ["content"] = "Write a limerick about lighthouses.", }, }, }); ``` ```php PHP theme={null} createChatCompletion([ 'model' => 'openai/gpt-6-astra', 'messages' => [[ 'role' => 'user', 'content' => 'Write a limerick about lighthouses.', ]], ]); echo $response['choices'][0]['message']['content']; ``` ```ruby Ruby theme={null} require 'phaseo_sdk' client = PhaseoSdk::Phaseo.new response = client.create_chat_completion( model: 'openai/gpt-6-astra', messages: [{ role: 'user', content: 'Write a limerick about lighthouses.' }] ) ``` ```java Java theme={null} import app.phaseo.sdk.Phaseo; import java.util.List; import java.util.Map; Phaseo client = new Phaseo(System.getenv("PHASEO_API_KEY")); var response = client.createChatCompletion(Map.of( "model", "openai/gpt-6-astra", "messages", List.of( Map.of("role", "user", "content", "Write a one-line haiku.") ) )); System.out.println(response.path("choices").path(0).path("message").path("content").asText()); ``` ```rust Rust theme={null} use phaseo::Phaseo; use serde_json::json; fn main() -> Result<(), Box> { let client = Phaseo::from_env()?; let response = client.chat_completions(&json!({ "model": "openai/gpt-6-astra", "messages": [ { "role": "system", "content": "Answer concisely." }, { "role": "user", "content": "What is provider fallback?" } ] }))?; let text = response .body .pointer("/choices/0/message/content") .and_then(|value| value.as_str()) .unwrap_or(""); println!("{text}"); Ok(()) } ``` | Language | Method | Returns | | - | - | - | | TypeScript | `client.generateText(request)`; `client.chat.completions.create(request)` does the same and switches to streaming when `stream` is true | `ChatCompletionsResponse` | | Python | `client.generate_text(request)`; also `client.chat.completions.create(request)` | `APIResponse` dict | | Go | `client.GenerateText(ctx, req)`, alias `CreateChatCompletion`; takes a `phaseo.ChatCompletionsRequest` | `map[string]interface{}` | | C# | `client.GenerateText(request)`, alias `CreateChatCompletion` | `Dictionary?` | | PHP | `$client->generateText($request)`, alias `createChatCompletion()` | Array | | Ruby | `client.generate_text(...)`, alias `create_chat_completion` | Hash | | Java | `client.createChatCompletion(request)`; takes a `Map` or Jackson `JsonNode` | Jackson `JsonNode` | | Rust | `client.chat_completions(&request)` | `PhaseoResponse`; the JSON is in `body` | Every return value has the Chat Completions shape: the reply is in `choices[0].message.content`, with `finish_reason` and `usage` alongside. ## Stream the response ```typescript TypeScript theme={null} for await (const chunk of client.streamChat({ model: "openai/gpt-6-astra", messages: [{ role: "user", content: "Stream a story" }], })) { if (chunk.text) process.stdout.write(chunk.text); } ``` ```python Python theme={null} for chunk in client.stream_chat({ "model": "openai/gpt-6-astra", "messages": [{"role": "user", "content": "Stream a story"}], }): if chunk.get("text"): print(chunk["text"], end="", flush=True) ``` ```java Java theme={null} import app.phaseo.sdk.Phaseo; import com.fasterxml.jackson.databind.ObjectMapper; import java.util.List; import java.util.Map; Phaseo client = new Phaseo(System.getenv("PHASEO_API_KEY")); var payload = Map.of( "model", "openai/gpt-6-astra", "messages", List.of(Map.of("role", "user", "content", "Hello")), "stream", true ); try (var lines = client.rawClient().requestLines( "POST", "/chat/completions", null, null, new ObjectMapper().writeValueAsString(payload) )) { lines.forEach(System.out::println); } ``` | Language | How to stream | | - | - | | TypeScript | `client.streamChat(request)` yields parsed chunks; `client.streamText()` yields the raw SSE lines. | | Python | `client.stream_chat(request)` yields parsed chunks; `client.stream_text()` yields the raw SSE lines. | | Java | `createChatCompletion` returns one JSON body. Set `stream: true` and send the request with `rawClient().requestLines`, which returns SSE lines as they arrive; close it with try-with-resources. | | Go, C#, PHP, Ruby, Rust | No Chat Completions streaming helper; leave `stream` unset. In C#, PHP and Ruby, [Responses](https://phaseo.app/docs/v1/sdk-reference/client/responses.md#stream-the-response) has a streaming method. | Each parsed chunk (TypeScript and Python) keeps the original fields (`choices`, `id`, …) and adds `text` (the content added by this chunk), `usage` and reasoning tokens (`reasoningTokens` / `reasoning_tokens`). ## Parameters Field names are the JSON body fields in every SDK. Go's typed `phaseo.ChatCompletionsRequest` uses PascalCase struct fields (`Model`, `Messages`). | Group | Fields | | - | - | | Required | `model`; `messages` with roles `system`, `developer`, `user`, `assistant` or `tool`, and content as a string or parts | | Sampling | `temperature` (0–2), `top_p` (0–1), `top_k` (-1 or more), `min_p` (0–1), `seed`, where the model supports them | | Length and penalties | `max_tokens` or `max_completion_tokens`, `presence_penalty` and `frequency_penalty` (-2 to 2), `repetition_penalty` (above 0), `stop` (string or array) | | Tools | `tools`, `tool_choice`, `max_tool_calls`, `parallel_tool_calls` | | Reasoning | `reasoning` object or `reasoning_effort` | | Log probabilities | `logprobs`, `top_logprobs` (0–20) | | Output | `response_format`, `n` (1–16), `stream`, `service_tier`, `metadata` (string values) | | Gateway | `provider` routing, `usage` (include usage), `meta` (include the gateway meta block) | [Parameters](https://phaseo.app/docs/v1/api-reference/parameters.md) explains each field, and the [Chat Completions API reference](https://phaseo.app/docs/v1/api-reference/endpoint/chat-completions.md) has the full schema. ## Response `ChatCompletionsResponse`: ```json theme={null} { "id": "chatcmpl-123", "object": "chat.completion", "created": 1677652288, "model": "openai/gpt-6-astra", "choices": [ { "index": 0, "message": { "role": "assistant", "content": "Hello there, how may I assist you today?" }, "finish_reason": "stop" } ], "usage": { "prompt_tokens": 9, "completion_tokens": 12, "total_tokens": 21 } } ``` With `stream: true`, the endpoint sends SSE frames that end with `data: [DONE]`: ``` data: {"id":"chatcmpl-123","object":"chat.completion.chunk","created":1677652288,"model":"openai/gpt-6-astra","choices":[{"index":0,"delta":{"role":"assistant","content":""},"finish_reason":null}]} data: {"id":"chatcmpl-123","object":"chat.completion.chunk","created":1677652288,"model":"openai/gpt-6-astra","choices":[{"index":0,"delta":{"content":"Hello"},"finish_reason":null}]} data: {"id":"chatcmpl-123","object":"chat.completion.chunk","created":1677652288,"model":"openai/gpt-6-astra","choices":[{"index":0,"delta":{},"finish_reason":"stop"}],"usage":{"prompt_tokens":9,"completion_tokens":12,"total_tokens":21}} data: [DONE] ``` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.