/**
* Anthropic Native Provider — direct API calls to api.anthropic.com.
*
* Set ANTHROPIC_API_KEY and you're done.
* Uses the Messages API (not OpenAI-compatible).
*
* API docs: https://docs.anthropic.com/en/api/messages
*/
import { Provider, ModelInfo, QueryOptions, QueryResponse } from "./provider.js";
/** Well-known Claude models. Updated as new models ship. */
const KNOWN_MODELS: ModelInfo[] = [
{ id: "claude-opus-4-6", name: "Claude Opus 4.6", provider: "anthropic" },
{ id: "claude-sonnet-4-5-20250929", name: "Claude Sonnet 4.5", provider: "anthropic" },
{ id: "claude-haiku-4-5-20251001", name: "Claude Haiku 4.5", provider: "anthropic" },
{ id: "claude-3-5-sonnet-20241022", name: "Claude 3.5 Sonnet", provider: "anthropic" },
{ id: "claude-3-5-haiku-20241022", name: "Claude 3.5 Haiku", provider: "anthropic" },
];
export class AnthropicProvider implements Provider {
name = "Anthropic";
private apiKey: string;
private baseUrl: string;
private apiVersion: string;
constructor(apiKey?: string) {
this.apiKey = apiKey ?? process.env.ANTHROPIC_API_KEY ?? "";
this.baseUrl = process.env.ANTHROPIC_BASE_URL ?? "https://api.anthropic.com";
this.apiVersion = "2023-06-01";
}
private headers(): Record<string, string> {
return {
"Content-Type": "application/json",
"x-api-key": this.apiKey,
"anthropic-version": this.apiVersion,
};
}
async healthCheck(): Promise<boolean> {
// Anthropic has no lightweight health endpoint.
// Verify the key works by attempting a minimal request.
// We use a cheap short prompt to avoid wasting tokens.
try {
const res = await fetch(`${this.baseUrl}/v1/messages`, {
method: "POST",
headers: this.headers(),
body: JSON.stringify({
model: "claude-3-5-haiku-20241022",
max_tokens: 1,
messages: [{ role: "user", content: "hi" }],
}),
});
// 200 = works, 401 = bad key, anything else = maybe works
return res.status !== 401;
} catch {
return false;
}
}
async listModels(): Promise<ModelInfo[]> {
// Anthropic doesn't have a reliable model listing endpoint.
// Return well-known models. The circuit breaker will disable
// any that fail at query time.
return KNOWN_MODELS;
}
async query(
model: string,
prompt: string,
options?: QueryOptions
): Promise<QueryResponse> {
const startTime = Date.now();
const body: Record<string, unknown> = {
model,
max_tokens: options?.max_tokens ?? 4096,
messages: [{ role: "user", content: prompt }],
};
if (options?.system_prompt) body.system = options.system_prompt;
if (options?.temperature !== undefined) body.temperature = options.temperature;
const res = await fetch(`${this.baseUrl}/v1/messages`, {
method: "POST",
headers: this.headers(),
body: JSON.stringify(body),
});
if (!res.ok) {
const errorText = await res.text();
throw new Error(`Anthropic query failed (${res.status}): ${errorText}`);
}
const data = (await res.json()) as {
content?: Array<{ type: string; text?: string }>;
model?: string;
stop_reason?: string;
usage?: {
input_tokens: number;
output_tokens: number;
};
};
const latency_ms = Date.now() - startTime;
const text = data.content
?.filter((c) => c.type === "text")
.map((c) => c.text ?? "")
.join("") ?? "";
return {
model,
content: text,
usage: data.usage
? {
prompt_tokens: data.usage.input_tokens,
completion_tokens: data.usage.output_tokens,
total_tokens: data.usage.input_tokens + data.usage.output_tokens,
}
: undefined,
latency_ms,
finish_reason: data.stop_reason ?? "stop",
};
}
}
