API reference - H Platform Docs

The Agents API is a JSON REST API. Every resource (agents, environments, sessions, skills, vaults, schedules, webhooks) has its own reference pages; this page holds the conventions they share.

Base URL

H runs isolated EU and US regions. Requests stay in-region: an EU key only ever reaches EU infrastructure. The REST API lives under /api/v2 and the MCP server under /mcp on each region’s host.

Region	Host
EU (default)	`https://agp.eu.hcompany.ai`
US	`https://agp.hcompany.ai`

The SDKs and CLI default to the EU host; see Client configuration to switch.

Authentication

Create a key at platform.hcompany.ai/settings/api-keys. It is shown once and scoped to your organization, so store it server-side. Send it as a bearer token on every request:

curl https://agp.eu.hcompany.ai/api/v2/sessions \
  -H "Authorization: Bearer $HAI_API_KEY"

The SDKs and CLI read HAI_API_KEY from the environment; see Authenticate.

Request and response format

Request bodies are JSON with Content-Type: application/json. Responses are JSON, except 204 No Content on deletes and on a changes poll with nothing new. Timestamps are ISO 8601 strings.

Errors

Non-2xx responses carry one envelope: message summarizes the problem, detail lists one entry per problem.

Error envelope

{
  "message": "Session not found.",
  "detail": [
    { "type": "not_found", "message": "Session not found." }
  ]
}

Status codes, the 422 detail shape, and SDK retry behavior are on Errors.

Pagination

List endpoints for sessions, agents, environments, skills, schedules, and webhooks take page (1-based, default 1) and size (default 10) and return a page envelope:

Page envelope

{
  "items": [],
  "page": 1,
  "total": 47
}

items holds the resources, page echoes the page you asked for, and total counts all matches. Responses do not echo size, so track it yourself: there are more pages while page * size < total. Each list page documents its size cap and sort options. Vaults and browser profiles use offset pagination: limit and offset in, total, limit, offset, and a named array out.

Idempotency

POST /sessions accepts an Idempotency-Key header so a retried create returns the original session. See Create a session for the key rules and the 409 / 422 responses.

Limits

There are no request-rate limits. Your plan caps tokens per billing period and concurrent sessions; both are readable from the API. See Plans and limits.

Resources

Resource	What it is	Path
Agents	Reusable configurations: model, instructions, environments, skills, tools	`/api/v2/agents`
Environments	The surfaces an agent perceives and acts on: a cloud browser, or a browser or desktop on your own machine	`/api/v2/environments`
Sessions	One run of an agent on a task	`/api/v2/sessions`
Skills	Reusable instruction fragments attached to agents	`/api/v2/skills`
Vaults	Site logins the agent uses, without secrets passing through the API	`/api/v2/vaults`
Schedules	Sessions created on a recurring cron cadence	`/api/v2/schedules`
Webhooks	Signed HTTP notifications when sessions change status	`/api/v2/webhooks`

​Base URL

​Authentication

​Request and response format

​Errors

​Pagination

​Idempotency

​Limits

​Resources