Files
Deng-m1andCursor 232fbc6dd8 feat: initial release of llm-fingerprint-detector
TypeScript library + CLI implementing single-token behavioral
fingerprinting of LLMs behind OpenAI-compatible APIs, per
'One Token Is Enough' (Bruckner, arXiv:2607.10252).

- Zero runtime dependencies (Node >= 18.17 built-in fetch)
- fingerprint / compare / verify API + llm-fingerprint CLI
- Jensen-Shannon divergence over per-cell answer distributions
- Reasoning-model aware (auto-disables hidden thinking channels)
- Bundled sample references for 11 popular models (CC-BY-4.0,
  derived from the paper's public Zenodo dataset)
- Unit + integration tests via node --test

Co-authored-by: Cursor <[email protected]>
2026-07-21 16:58:00 +08:00

53 lines
1.8 KiB
JavaScript

/**
* Example 2 — verify that a cheap/unknown endpoint really serves the model it
* claims, by comparing its live fingerprint against a reference.
*
* Run (from the package root, after `npm run build`):
* SUSPECT_API_KEY=sk-... node examples/02-verify-endpoint.mjs
*
* The reference here is a bundled sample derived from the paper's public
* dataset (CC-BY-4.0) — handy for a demo. For real audits, collect your own
* reference from the official API with example 01 and load that file instead.
*/
import { verify } from '../dist/index.js'
import { loadBundledReference } from '../dist/reference.js'
const apiKey = process.env.SUSPECT_API_KEY
if (!apiKey) {
console.error('Set SUSPECT_API_KEY for the endpoint you want to test.')
process.exit(1)
}
// Endpoint under test: does it really serve gpt-4o-mini?
const suspectEndpoint = {
baseUrl: 'https://openrouter.ai/api/v1', // ← put the reseller/aggregator URL here
model: 'openai/gpt-4o-mini',
apiKey,
}
const reference = loadBundledReference('openai/gpt-4o-mini')
const result = await verify(suspectEndpoint, reference, {
cells: 8,
samplesPerCell: 25,
onProgress: (e) => {
if (e.stage === 'sampling') process.stderr.write(`\r${e.done}/${e.total}`)
},
})
process.stderr.write('\n')
for (const warning of result.warnings) console.warn(`warning: ${warning}`)
console.log(`verdict: ${result.verdict}`)
console.log(`mean JSD: ${result.meanJsd?.toFixed(3)} over ${result.comparison.comparableCellCount} cells`)
console.log('baselines: same model ≈ 0.14 · cross-provider ≈ 0.227 · different model ≈ 0.463')
console.log('\nmost divergent cells:')
for (const cell of result.comparison.cells.slice(0, 5)) {
console.log(` ${cell.cellId.padEnd(26)} JSD ${cell.jsd.toFixed(3)}`)
}
// CI-style decision:
process.exitCode = result.verdict === 'match' ? 0 : 1