> ## Documentation Index
> Fetch the complete documentation index at: https://www.agent37.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Health & version

> Probe whether an instance's agent is ready, and read the gateway build.

Both endpoints live on the instance URL, not the hosting API: the base is `https://{instanceId}.agent37.app`, with the same `sk_live_` key sent as the `X-Agent37-Key` header. See [Instance and preview URLs](/docs/agents-api/urls).

## Health

`GET /v1/health` returns `{ "ok": true, "agent": "hermes", "healthy": true, "hermes": true }`. `ok` is true whenever the gateway is up; `agent` is the harness that was probed, and `healthy` reports whether that harness behind it is reachable. By default it probes the instance's configured harness; pass `?agent=`, `hermes`, `openclaw`, `claude-code`, `codex`, `grok`, or `opencode`, to probe a specific one (an unknown value is `400 validation_error`, and an empty value is the same as omitting it). An unreachable or unprovisioned harness reports as `healthy: false` with a `200`; so does `claude-code` until a [Claude account is connected](/docs/agents-api/claude-code#connect-your-claude-account), `codex` until an [OpenAI account is connected](/docs/agents-api/codex#connect-your-openai-account), and `grok` until an [xAI key is set](/docs/agents-api/grok). When Hermes is probed, the body also carries a `hermes` field mirroring `healthy`, kept for backward compatibility; other harnesses omit it. Use it as a readiness probe after [create or start](/docs/agents-api/instances): the create call returns as soon as the instance's computer is up, while the agent inside is still booting, and a start that boots the instance fresh (a stopped instance, or a [wake](/docs/agents-api/instances#auto-sleep) that has to rebuild it because the checkpoint could not be restored or the instance was moved to another host or to cold storage) returns `running` the same way, before the agent is ready. Poll until `healthy` is `true` before sending work; `ok` alone only tells you the gateway is answering.

<CodeGroup>
  ```bash curl theme={null}
  curl https://ab12cd34ef.agent37.app/v1/health \
    -H "X-Agent37-Key: sk_live_..."
  ```

  ```json response theme={null}
  { "ok": true, "agent": "hermes", "healthy": true, "hermes": true }
  ```
</CodeGroup>

## Version

`GET /v1/version` returns the gateway build as `{ "name": "agent37-gateway", "version": "<semver>" }`, where `version` is the gateway release pinned in the instance's image.