> ## Documentation Index
> Fetch the complete documentation index at: https://hub.hcompany.ai/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> H Platform has four products: the Agents API (managed computer-use agents, base URL https://agp.eu.hcompany.ai/api/v2 or https://agp.hcompany.ai/api/v2 for the US), the Models API (OpenAI-compatible Holo vision-language models at https://api.hcompany.ai/v1), HoloDesktop CLI (Holo on the user's own desktop), and HoloTab (a free no-code Chrome extension that runs Holo in the user's browser, with recordable routines and schedules).
> Authenticate with a bearer API key from the HAI_API_KEY environment variable. SDKs: `pip install hai-agents` (Python, `from hai_agents import Client`) and `npm install hai-agents` (TypeScript, `import { HaiAgentsClient } from "hai-agents"`). CLI: `hai`.
> Agents do work in a browser or on a desktop; describe the task as an imperative instruction. To run a task quickly, prefer the pre-built agent `h/web-surfer-flash`. Read results from the session's `latest_answer` after it reaches a terminal status.
> Sessions are the unit of work; wait for a terminal status (completed, failed, timed_out, interrupted) before reading the answer. Use webhooks or the `changes` long-poll endpoint to follow progress.

# API reference

> Models API base URL, bearer authentication, OpenAI-compatible endpoints, response channels, rate limits per tier, and error codes.

The Models API is OpenAI-compatible: point the official OpenAI client (or any compatible library) at H Company's endpoint. Tools use the standard `tools` and `tool_calls` fields. Holo-specific behavior (reasoning, structured outputs, and the coordinate convention) comes through a few extra fields documented here.

## Endpoints

<CardGroup cols={2}>
  <Card title="POST /chat/completions" icon="message" href="/models-api/chat-completions">
    The inference endpoint: parameters, response fields, streaming.
  </Card>

  <Card title="GET /v1/models" icon="list" href="/models-api/list-models">
    Discover served models, limits, pricing, and deprecation dates at runtime.
  </Card>
</CardGroup>

## Endpoint and auth

| | |
| :- | :- |
| Base URL | `https://api.hcompany.ai/v1/` |
| Auth | `Authorization: Bearer $HAI_API_KEY` (handled by the OpenAI client) |
| Keys | Create one on [H Platform](https://portal.hcompany.ai/?product=modelsapi\&source=docs) |

The [Quickstart](/models-api/quickstart) shows the client setup in Python, TypeScript, and cURL. Model IDs, per-model limits, pricing, and tiers live on the [Models](/models-api/introduction#models) page.

## The two response channels

Every call returns `message.content` (the action or answer) and `message.reasoning` (the thinking trace, read-only). Field-by-field details are in the [chat completions reference](/models-api/chat-completions#response); how to carry state across turns is in [Core concepts](/models-api/build-an-agent/core-concepts#reasoning).

## Conventions

Coordinates in `[0, 1000]`, the 3-screenshot image budget, choosing between structured outputs and function calling, and passing Holo-specific fields through the OpenAI SDKs are covered in [Core concepts](/models-api/build-an-agent/core-concepts).

## Rate limits

| Tier | Rate limit | Models | How to get there |
| - | - | - | - |
| Free | 10 requests per minute | `holo3-1-35b-a3b` | Create an account. No credit card. |
| Paid | Higher limits | All models | [Add credits](https://portal.hcompany.ai/credits?product=modelsapi\&source=docs). Up to 15 minutes to appear. |

The [credit dashboard](https://portal.hcompany.ai/credits) shows your balance and usage. The balance is checked before a request runs, so a large request on a low balance can overshoot by a few cents; contact [support@hcompany.ai](mailto:support@hcompany.ai) if it keeps growing. Unused credits may expire one year after purchase and are not refundable by default, subject to regional obligations and the [terms of use](https://hcompany.ai/terms-of-use).

## Errors

| Error | Cause | What to do |
| - | - | - |
| `model_not_found` | The model ID was removed after its [`deprecation_date`](/models-api/list-models). | Switch to a served ID from `GET /v1/models`. |

## Next steps

<CardGroup cols={3}>
  <Card title="Chat completions" icon="message" href="/models-api/chat-completions">
    Full parameter and response reference.
  </Card>

  <Card title="Models" icon="microchip" href="/models-api/introduction#models">
    IDs, limits, pricing, lifecycle.
  </Card>

  <Card title="Build an agent" icon="arrows-rotate" href="/models-api/build-an-agent/core-concepts">
    The loop conventions Holo is trained on.
  </Card>
</CardGroup>


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