[jehrr]

Problem

A reCAPTCHA v2 widget rendered from a .g-recaptcha element loads api.js with no render parameter. The live detector had no rule for "no size, no render", so both the checkbox and the invisible form fell to its last branch and were classified v3. A v3 task bought for a v2 widget is refused by the solver (ERROR_CAPTCHA_UNSOLVABLE in the manual test that reported this).

The report saw the invisible demo come out as a plain checkbox; measured here it came out as v3, the same as the checkbox demo. Either way it was the wrong task type.

The HTML-only detector had the same mistake in another place: it labelled grecaptcha.render, which is v2's explicit-render call, as v3.

Behaviour after

Classification, strongest signal first:

signal	kind
loader render=<sitekey>	v3 (v3 cannot load without it)
render=explicit	v2, invisible if the client says so
loader seen, no render	v2; the badge then means invisible
loader not seen	the previous fallback, unchanged

The badge is checked only after v3 has been ruled out, because v3 draws .grecaptcha-badge too. The discovery script now records whether the api.js/enterprise.js loader is on the page at all (loaderSeen); without it, "no render" means nothing.

Static detector: data-sitekey + grecaptcha.render → v2.

Evidence (2026-10-22, Google's own demo pages)

page	before	after
v2 checkbox, implicit	v3	v2
v2 invisible, implicit (two demos)	v3	v2-invisible
v2 checkbox, render=explicit	v2	v2
v3, render=<key>	v3	v3

• The same in Playwright, Selenium and pyppeteer.
• Paid check, bounded: with the corrected kind, the v2 checkbox and v2 invisible demos were solved (36 s and 15 s) and accepted by Google ("Verification Success"), $0.00299 total.
• On the demos, grecaptcha.render appears only on the v2 explicit page and grecaptcha.execute only on the v3 page.

Tests

• captures/recaptcha_discovery.json: what the discovery script returned on those pages, with sitekeys replaced by demo-sitekey (equality with render preserved, which is all the classifier reads). Pins the kind per page, plus "v3 has a badge and stays v3", "no loader seen falls back" and both static rules.
• .gitignore ignored every *.json, so this fixture would never have reached git and its check would have skipped in CI, which reads as green. !captures/*.json added, plus a check that fails on any file in captures/ that git would not commit.
• Controls in disposable copies, each caught by the named check: implicit-render rule removed, badge decides before v3 is ruled out, loader presence ignored, static render back to v3, JSON captures ignored again — 5 of 5.
• Offline suite green with core requirements and in each engine venv; credential scan clean (59 files).

🤖 Generated with Claude Code

https://claude.ai/code/session_01VrpkXSoXyZMGV5nqF9JV6P