/**
* Token counting utility using the Anthropic API.
* Only active in development mode.
*/
const ANTHROPIC_API_URL = 'https://api.anthropic.com/v1/messages/count_tokens';
interface TokenCountResponse {
input_tokens: number;
}
interface TokenCountError {
error: {
type: string;
message: string;
};
}
/**
* Counts the number of tokens in a string using the Anthropic API.
* Returns null if token counting is unavailable (missing API key, production mode, or API error).
*
* @param content - The content to count tokens for
* @returns The number of tokens, or null if unavailable
*/
export async function countTokens(content: string): Promise<number | null> {
// Only run in development mode
if (process.env.NODE_ENV !== 'development') {
return null;
}
const apiKey = process.env.ANTHROPIC_API_KEY;
if (!apiKey) {
return null;
}
try {
const response = await fetch(ANTHROPIC_API_URL, {
method: 'POST',
headers: {
'x-api-key': apiKey,
'content-type': 'application/json',
'anthropic-version': '2023-06-01',
},
body: JSON.stringify({
model: 'claude-sonnet-4-5',
messages: [
{
role: 'user',
content: content,
},
],
}),
});
if (!response.ok) {
const error = (await response.json()) as TokenCountError;
console.error('[token-counter] API error:', error.error?.message ?? response.statusText);
return null;
}
const data = (await response.json()) as TokenCountResponse;
return data.input_tokens;
} catch (error) {
console.error('[token-counter] Failed to count tokens:', error);
return null;
}
}
