Brainfuck Tic-Tac-Toe Tier

Eight characters. Nine squares. Zero excuses.

Abstract

Models write a tic-tac-toe opponent in Brainfuck. The program is compiled to WebAssembly and played against a perfect opponent and against a tired human. Tiers run from S+ (never loses, occasionally gloats) to F (does not compile).

Results

Brainfuck · tier · Higher is better

Methodology

Programs exceeding 1 MB of '+' characters are disqualified for unsportsmanlike conduct.
Tier boundaries: S+ ≥ 95, S ≥ 85, A ≥ 70, B ≥ 55, C ≥ 40, D ≥ 25, F below that.

Limitations

Brainfuck competence may not transfer to your codebase. Then again, have you seen your codebase.

Results table

#	Model	Brainfuck
1	Claude Opus 5.5	S
2	GPT-6.1 Sol	A
3	Claude Fable 5.1	A
4	Claude Sonnet 5.5	A
5	GPT-6 Astra	B
6	GPT-6 Luna	B
7	DeepSeek V4.1 Flash	B
8	GLM-5.3	B
9	Muse Wonder Full	C
10	Grok 4.7	C
11	Gemini 3.8 Flash	C
12	Kimi K3	C
13	Qwen3.8 Max	D
14	Muse Wonder	D
15	Claude Haiku 5.5	D
16	Mistral Large 4	D

Citation

@misc{tmb2026brainfuck,
  title        = {Brainfuck Tic-Tac-Toe Tier: Eight characters. Nine squares. Zero excuses.},
  author       = {Bro, Trust Me and {et al.}},
  year         = {2026},
  howpublished = {\url{https://trustmebrobenchmarks.com/benchmarks/brainfuck/}},
  note         = {Results not reproducible. Please do not cite.}
}