> ## 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 If a page is wrong or out of date, report it with the MCP `submit_feedback` tool.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 <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.

# OpenAI SDK

> Use official OpenAI SDKs with Phaseo.

Use this guide when your app already calls OpenAI from TypeScript, JavaScript, or Python. Change only the API key, base URL, and model id.

## TypeScript

```bash theme={null}
npm install openai
```

```ts theme={null}
import OpenAI from "openai";

const client = new OpenAI({
	apiKey: process.env.PHASEO_API_KEY,
	baseURL: "https://api.phaseo.app/v1",
});

const response = await client.responses.create({
	model: "openai/gpt-5-nano",
	input: "Write one sentence about reliable model routing.",
});

console.log(response.output_text);
```

## Python

```bash theme={null}
pip install openai
```

```python theme={null}
import os
from openai import OpenAI

client = OpenAI(
    api_key=os.environ["PHASEO_API_KEY"],
    base_url="https://api.phaseo.app/v1",
)

response = client.responses.create(
    model="openai/gpt-5-nano",
    input="Write one sentence about reliable model routing.",
)

print(response.output_text)
```

## Chat Completions

Older libraries may still call Chat Completions:

```ts theme={null}
const completion = await client.chat.completions.create({
	model: "openai/gpt-5-nano",
	messages: [{ role: "user", content: "Reply with only: ok" }],
});
```

## Notes

* Use Phaseo model ids, including provider prefixes such as `openai/`, `anthropic/`, or `google/`.
* Server tools use Phaseo tool names such as `phaseo:web_search`.
* For Anthropic-native clients, use the [Anthropic SDK](https://phaseo.app/docs/v1/guides/integrations/anthropic-sdk.md) guide instead.

## Related

* [Responses API](https://phaseo.app/docs/v1/api-reference/endpoint/responses.md)
* [Chat Completions](https://phaseo.app/docs/v1/api-reference/endpoint/chat-completions.md)
* [Server Tools](https://phaseo.app/docs/v1/guides/server-tools.md)


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