Step 27: assistant

text

I've assessed the claim as **supported** (confidence 0.65, credence 0.68). The evidence favours a sustained acceleration in Anthropic's capability trend since late 2025 over a one-time jump, but it doesn't establish it. The evidence comes almost entirely from one assessor, METR, and Anthropic redacted most of the evidence METR found most informative.

**Evidence for sustained acceleration** (from the two METR reports dated 5 November 2026, which I read):
- **Benchmark trend:** Scores on AECI, Anthropic's version of the Epoch Capabilities Index, have grown about 1.9 times their pre-October 2025 rate (95% interval 1.5 to 2.8). The estimate holds at 1.9 to 2.1 times across METR's alternative fitting choices.
- **Newer models:** METR says newer internal models make a permanent slope change look more plausible than a one-time jump at the Mythos Preview model. Later snapshots of one unreleased model ("Model 2") kept adding to the gap, against the reading in Anthropic's own August 2026 Risk Report.
- **Internal indicators:** Leading indicators show acceleration of 1.3 to 2.8 times, and the redacted pipeline data suggest it may be above 2 times and rising.

**Evidence against or limiting it:**
- **Anthropic's own reading:** The August 2026 Risk Report read the data as weak evidence for a one-time jump. METR agrees the data from that time couldn't tell the two explanations apart.
- **Comparison with other developers:** If non-Anthropic models are included, the estimate falls to about 1.4 times. That leaves room for part of the change being a one-off catch-up from behind the frontier.
- **Thin data:** The index rests on few models, and the newest are near the ceiling on most of its benchmarks. Fitting to the benchmarks could also make the slope look steeper than it is.

New models released over the next several months should settle it. Continued gains above the old trend would strengthen the claim; a return to the pre-2025 slope would undercut it.

**What I added to the claim's page:**
- One argument for the claim, which I rated "likely if its premises hold". It links two existing nodes: the claim that benchmark growth roughly doubled, and the quantity for leading-indicator acceleration.
- One argument against, rated "slight". It links the existing quantity for acceleration across all developers.
- Four passages from METR's review that hadn't been matched to any argument at intake: one is now recorded under the argument for, and the other three were dismissed as repeats from the same source.

I also set importance at 0.55 and contestation at 0.55, logged the decision, and answered both inbox messages. Nothing depends on this claim yet, so there was no one to notify. The pass spent $0.66 of the $1.00 budget.