Detection

The SDK identifies three classes of agent. They are not symmetric — some are exact-match, some are heuristic, some are not detectable at all from the page. Being upfront about that asymmetry is the most important thing on this page.

Class	How we detect	Confidence
WebMCP	navigator.modelContext is set by the agent's browser/extension	Exact — confidence: 1
DOM-driver	A weighted bag of automation signals (Playwright, Puppeteer, Selenium…)	Heuristic — confidence: 0.0–1.0
Screenshot model	Cannot be detected client-side. Use declareAgent().	Declared — trust: 'declared' | 'verified'

Running detection

import { Agentronics } from '@agentronics/sdk'
 
const client = Agentronics.init({ publishableKey: process.env.NEXT_PUBLIC_AGENTRONICS_KEY! })
 
const identity = await client.detect()
// → { class: 'webmcp', trust: 'detected', confidence: 1, vendor: 'claude-extension', … }
// or null if no agent fires above threshold

detect() runs WebMCP first (with a short poll for late-injecting extensions), then falls back to DOM heuristics. The first class that matches wins.

Tuning

await client.detect({
  webmcp: { pollMs: 500 },     // 0 to skip the poll, false to skip WebMCP entirely
  dom:    { threshold: 0.4 },  // raise to be stricter, false to skip DOM heuristics
})

Agents declaring themselves

Screenshot agents — and any agent that wants higher trust than detection alone provides — should call declareAgent():

import { declareAgent } from '@agentronics/sdk'
 
const id = declareAgent({
  class: 'screenshot',
  vendor: 'browser-use',
  verificationToken: '<token from your verification endpoint>',
})
// → trust: 'verified' if a token is supplied, otherwise 'declared'

verified requires the gateway to validate the token against the customer's configured verification endpoint. That validation lands with the gateway in Phase 8.

What we deliberately do not do

• No fingerprinting beyond detection. No canvas hashes, no audio context probes, no font enumeration.
• No silent retries to defeat anti-detection tooling. If a sophisticated DOM-driver scrubs navigator.webdriver, it passes as human and that's the right answer for v0.1.
• No server-side header inspection in v0.1. That belongs to a future edge product.

See research/phase-0.5-detection-spike.md in the repo for the full methodology, signal weights, and decision log.