The native Claude provider for the Apograph copilot

A ModelProvider over Anthropic’s own SDK. The default for tool-heavy work, and the path on which native capabilities stay available.

The only package allowed a vendor SDK

The copilot’s domain and server packages must not import one, ever — the same rule that keeps Drizzle and Nest out of any domain layer.

An adapter is where a vendor’s client belongs, because an adapter is the thing you replace.

Install

npm install @apograph/copilot-provider-anthropic

import { createAnthropicProvider } from '@apograph/copilot-provider-anthropic';

CopilotPlugin({
    providers: [
        { name: 'claude', provider: createAnthropicProvider(config.plugins.copilot.providers.claude) },
        { name: 'fake', provider: createFakeProvider() }
    ],
    config: config.plugins.copilot
});

Configuration

{ apiKey, models, baseUrl?, effort?, maxRetries?, timeoutMs?, promptCaching? }

Variable	Default	What it does
`ANTHROPIC_API_KEY`	unset	Setting it is what registers this backend
`COPILOT_ANTHROPIC_MODELS`	see below	Comma-separated. The first is the default
`ANTHROPIC_BASE_URL`	unset	A gateway, proxy or regional endpoint

COPILOT_ANTHROPIC_MODELS=claude-opus-5,claude-sonnet-5,claude-haiku-4-5

A missing key un-registers the backend, it does not break it

Leave ANTHROPIC_API_KEY empty and there is no claude in the model picker at all — rather than one that fails on the first message.

That is the composition root’s job: apograph.config.ts omits a provider whose connection settings are absent, and plugins.ts skips registering it.

The key never leaves the server.

The model list is a list

One key and one client back several models, so a user can switch mid-conversation without a redeploy. The first entry is the default, and it is what the admin’s picker opens on.

A run naming a model outside the list raises an unknown-model error rather than quietly answering on the default. A silent substitution is the kind of thing nobody notices until a bill or an answer looks wrong.

The lazy client

The SDK client is constructed on first use, not in the factory.

A host registers every provider it might route to, but an operator running local inference has no Anthropic key — and an unused adapter must not fail their boot. Constructing eagerly would make registering this package a hard dependency on having configured it.

Capabilities are probed

The adapter asks the Models API what the configured models support, and falls back to a conservative set when that call cannot be made. That is what lets the run engine know whether a native capability is available without a table in this repository going stale every time a model ships.