prelude-2

Features of prelude-2

Inside the model, every token is a list of numbers that mix many things at once. A sparse autoencoder, trained on the residual stream after block 4, splits it into 4,096 directions, few of them active at a time: each one tends to mean one thing, like “the last digit of a number” or “a story begins”. Shaded tokens show where a feature fires.

Features: 4,096
Loss recovered: 98.9%
Variance unexplained: 7.3%
Model loss, with the features: 2.565 → 2.631

4,096 features.

#1144
Fires on “0”
worksheet 0.83% of tokens

52039+48267:
#1145
Fires on “ but”
python 0.56% of tokens

item` should return the biggest item of nums, but it has
#1146
Fires on “0”
python 1.41% of tokens

, 0, 1]) == [10,
#1147
Fires on “ number”
worksheet 0.47% of tokens

tail(items)`.<|assistant_end|><|bos|><|system_start|>Answer with the number only.
#1148
Fires on “ lived”
python 0.50% of tokens

and shared them with their friends. And they all lived happily ever
#1149
Fires on “ loud”
story 0.48% of tokens

started to climb the wall, but he heard a loud bark.
#1150
Fires on “ when”
story 0.74% of tokens

then we can eat them and share them with dad when he comes
#1151
Fires on “⏎”
python 0.26% of tokens

final_letter("music") == "c"⏎assert final
#1152
Fires on “ ”
python 0.52% of tokens

example, `evens([1, 5, 2])`
#1153
Fires on “ then”
story 0.88% of tokens

surprised because it
#1154
Fires on “6”
worksheet 0.22% of tokens

67⏎5
#1155
Fires on “9”
worksheet 2.06% of tokens

6242 = 6249.⏎
#1156
Fires on “Once”
story 0.41% of tokens

py`.<|assistant_end|><|bos|>Once upon a
#1157
Fires on “ the”
story 0.80% of tokens

walking through the forest when
#1158
Fires on “9”
worksheet 0.66% of tokens

56⏎6+9: 6+9+1
#1159
Fires on “ob”
agent 1.96% of tokens

"))⏎⏎$ python3 main.py⏎olle
#1160
Fires on “ ”
worksheet 0.66% of tokens

⏎```<|assistant_end|><|bos|><|user_start|>Add 82 and 88
#1161
Fires on “ big”
story 0.50% of tokens

ate their sandwiches.⏎Suddenly, a big bird flew
#1162
Fires on “3”
worksheet 1.06% of tokens

⏎00+63: 0+3+1
#1163
Fires on “ best”
agent 0.83% of tokens

small, angry
#1164
Fires on “+”
worksheet 0.34% of tokens

9: 5+9=
#1165
Fires on “ rain”
story 0.85% of tokens

to make the blouse come to life.⏎Blue started
#1166
Fires on “.”
agent 0.35% of tokens

.<|assistant_end|><|bos|>
#1167
Fires on “ if”
python 0.34% of tokens

nums):⏎ return [n for n in nums if n %
#1168
Fires on “ Max”
story 0.85% of tokens

upon a time, there was a little bunny named Bobo. Bobo
#1169
Fires on “ place”
story 0.65% of tokens

! Tom was sad because he could not find a way to get
#1170
Fires on “ question”
agent 0.90% of tokens

question, read
#1171
Fires on “ and”
worksheet 0.26% of tokens

sum of the
#1172
Fires on “ a”
story 0.33% of tokens

<|user_start|>Tell me a story.<|user_end|><|assistant_start|>Once upon a time,
#1173
Fires on “'m”
story 0.76% of tokens

dog felt very sorry. He said, "I am so sorry
#1174
Fires on “<|tool_call_start|>”
chat 3.18% of tokens

files<|user_end|><|assistant_start|><|tool_call_start|>gl
#1175
Fires on “6”
worksheet 0.17% of tokens

86373 and 33838
#1176
Fires on “ of”
python 0.29% of tokens

104550.<|bos|>The sum of 8
#1177
Fires on “ harness”
agent 0.47% of tokens

an AI agent running in OpenCode, a coding agent harness.<|system_end|>
#1178
Fires on “ she”
story 1.28% of tokens

ary was three and she liked playing
#1179
Fires on “1”
worksheet 1.65% of tokens

, 113<|think_end|>The answer is 113
#1180
Fires on “_”
agent 0.48% of tokens

<|bos|># number_utils.py⏎def sum_up_
#1181
Fires on “ ”
agent 0.51% of tokens

3, 7, 1, 3]))⏎
#1182
Fires on “ ”
agent 3.36% of tokens

x > 5` with `return x > 0`.
#1183
Fires on “,”
worksheet 0.84% of tokens

: 6+6+1=13, 3
#1184
Fires on “ much”
chat 0.43% of tokens

9.<|assistant_end|><|bos|>How much is
#1185
Fires on “ to”
story 0.40% of tokens

. He said, "Let's use this blanket to keep dry
#1186
Fires on “Look”
story 0.20% of tokens

around in the air.⏎"Look, Amy
#1187
Fires on “ function”
agent 0.72% of tokens

a coding agent harness.<|system_end|><|user_start|>"Add a function initial to
#1188
Fires on “ sitting”
story 0.70% of tokens

Tim got to Sue's house, he saw her sitting on her
#1189
Fires on “ me”
agent 0.42% of tokens

([7, 5, 9, 6,
#1190
Fires on “ read”
agent 0.69% of tokens

edit, glob, grep, question, read, shell
#1191
Fires on “.”
worksheet 0.33% of tokens

flowers. Mia gets 177 more flowers. How many
#1192
Fires on “ we”
agent 0.69% of tokens

full of toys! All the kids were so surprised and happy.
#1193
Fires on “ can”
chat 0.40% of tokens

by step or with a calculator.<|assistant_end|><|user_start|>How can you help