"About a quarter of them contained bugs": Gemini 4's ML R&D benchmark

On LessWrong, Simon Mendelsohn examines Google DeepMind's Gemini 4 Argon safety report, which rules out its AI-research-automation threshold using an internal benchmark that the report's own audit says has about a quarter of tasks unpassable. Mendelsohn agrees with the verdict but asks Google to disclose the numbers.

Why it matters

The same thing, for different readers.

What it means for you

The tests used to say whether a new AI could automate AI research were partly broken, so a reassuring result says less than it appears to.

For lawmakers

Safety frameworks that rely on pass-rate thresholds need disclosed denominators and audited benchmarks; the author argues regulation should require more transparency of this kind.

For researchers

Unpassable tasks only lower a capability score, so bugs bias rule-out tests toward false reassurance; the post requests scored subset size, bug counts and timeouts.

The question it raises

If a refusal triggered by evaluation awareness looks the same as failure, tests cannot separate what a model won't do from what it can't.

In their own words

Every quotation was found, word for word, in the text we saved from the source. That shows the words are there; it does not make them true, or prove the speaker meant them as quoted.

From the source’s own text.

“During this evaluation cycle, we audited the subset of original challenges that remain in the current suite. About a quarter of them contained bugs that prevent any submission from passing (e.g. crashing verifiers, incorrect ground truth), and several more were graded against details not stated in the task.”
Google DeepmindPassage from Google DeepMind's Gemini 4 Argon safety report (p.67) as quoted by the author, describing an audit of its internal ML R&D benchmark.
Found word for word in the sourceAs quoted in the text we read, not the speaker’s own text or a transcript of their words
“Our conclusion that Gemini 4 is below the threshold is robust to these issues: Gemini 4 would remain below the threshold even if every incomplete trajectory had succeeded.”
Google DeepmindGoogle DeepMind's safety report (p.67) as quoted by the author, on why timeouts and bugs do not change its conclusion.
Found word for word in the sourceAs quoted in the text we read, not the speaker’s own text or a transcript of their words
“An unpassable task only lowers the score, never raises it. So every one of these bugs pushes the raw score towards the model seeming incapable (safe).”
Simon MendelsohnThe author's argument for why benchmark bugs in a capability rule-out test bias results in one direction.
Found word for word in the source
“I’m not reassured that Google will actually be able to tell if the next model passes thresholds.”
Simon MendelsohnThe author's conclusion after agreeing that Gemini 4 Argon is probably not at the critical level.
Found word for word in the source

How the finding was reached

In our words, from the source. Weigh the finding by how it was made.

What was done
A reading of Google DeepMind's Gemini 4 Argon safety report and public summaries of it, focused on the internal ML R&D benchmark (GRB) used to rule out the automation threshold.
What it found
Per the report as quoted, about a quarter of audited original tasks had bugs preventing any pass; many runs timed out; of completed runs the model solved roughly half, and Google says the conclusion holds even counting bugged tasks or unfinished runs as passes.
What it does not show
The post cannot see the benchmark and relies on the report's text; the size of the scored subset, the number of bugged tasks and the denominator of the 90% rule are not disclosed.
Status
A report

The record

Questions
What happens when AI helps build more capable AI? · Are AI companies putting stronger safeguards into practice?
People
Simon Mendelsohn (Wrote it)
What we read
We read the whole source.
Found by
The Radar, run of October 17, 2026, via lesswrong (tier 1: the source’s own channel or an official record)
Cite this
LessWrong, “"About a quarter of them contained bugs": Gemini 4's ML R&D benchmark”, October 16, 2026. Entry in the Ctrl AI Base, https://ctrlai.com/base/lesswrong-2026-10-16-gemini-4-ml-rd-benchmark-bugs
Our notesThe two Google quotations are the report's words as reproduced by the post, not checked against the report itself (the post says the report PDF was updated Oct 16). The speaker id for those is the organization. The post is a personal blog by a commentator; its reading that the report did not state which set the verdict used is its own.