Is BFCL v4 still meaningful?
Status:Flawed Checked against the report, 5 November 2026
Verdict
No. Epoch AI rates it Flawed, and one task rewards declining the call.
Why flawed: Epoch AI rated BFCL v4 Flawed on 10 September 2026.[1][1] Epoch's benchmark reviews The Neuron Secondary
What “Flawed” meansKnown problems
- One task rewards declining a tool call.[1][1] Epoch's benchmark reviews The Neuron Secondary
What to look at instead
The report names no direct successor.
Where it appears in the report
Chapter 1, Benchmarks
- Figure 5. Thirteen Flawed verdicts in ten weeks
- Table 4. Epoch AI Benchmark Review verdicts and the main defects found, August to October 2026 in “Go deeper: Epoch's verdicts, benchmark by benchmark”
- Table 7. General and computer-use agent benchmarks, November 2026 in “Go deeper: General and computer-use agent benchmarks (18)”
Sources
Copied from the chapter source lists. Each number links back to the source in its chapter.
- [1] Epoch's benchmark reviews, The Neuron. It reports nine Flawed and four Verified ratings on 18 Sep 2026. Secondary theneuron.ai Chapter 1, source 36