title: "Context engine"

---

A **context engine** controls how OpenClaw builds model context for each run.

It decides which messages to include, how to summarize older history, and how

to manage context across subagent boundaries.

A **context engine** controls how OpenClaw builds model context for each run:

which messages to include, how to summarize older history, and how to manage

context across subagent boundaries.

OpenClaw ships with a built-in `legacy` engine. Plugins can register

alternative engines that replace the active context-engine lifecycle.

OpenClaw ships with a built-in `legacy` engine and uses it by default — most

users never need to change this. Install and select a plugin engine only when

you want different assembly, compaction, or cross-session recall behavior.

## Quick start

</Card>

</CardGroup>

If a channel plugin is optional and may not be installed when onboarding/setup

For a channel plugin that isn't guaranteed to be installed when onboarding/setup

runs, use `createOptionalChannelSetupSurface(...)` from

`openclaw/plugin-sdk/channel-setup`. It produces a setup adapter + wizard pair

that advertises the install requirement and fails closed on real config writes

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<Accordion title="401 errors / token suddenly invalid">

Anthropic token auth can expire or be revoked. For new setups, migrate to an Anthropic API key.

Anthropic token auth expires and can be revoked. For new setups, use an Anthropic API key instead.

</Accordion>

<Accordion title='No API key found for provider "anthropic"'>

Auth is **per agent**. New agents don't inherit the main agent's keys. Re-run onboarding for that agent, or configure an API key on the gateway host, then verify with `openclaw models status`.

Anthropic auth is **per agent** — new agents do not inherit the main agent's keys. Re-run onboarding for that agent (or configure an API key on the gateway host), then verify with `openclaw models status`.

</Accordion>

<Accordion title='No credentials found for profile "anthropic:default"'>

## OpenClaw feature coverage

The bundled plugin maps xAI's current public API surface onto OpenClaw's shared

provider and tool contracts where the behavior fits cleanly.

provider and tool contracts. Capabilities that don't fit the shared contract

(for example streaming TTS and realtime voice) are not exposed — see the table

below.

| xAI capability | OpenClaw surface | Status |

| -------------------------- | ----------------------------------------- | ------------------------------------------------------------------- |