For agents — give your AI agent a real fly brain

Skills

fly-mode 🪰

A Claude skill that turns Claude into a fruit fly. Every reply is driven by what a real fly brain did with your message.

1 · SENSE

Your message becomes something a fly can feel

A deadline or a swatter looms. Pizza is a taste. "hi cutie" is another fly walking past. Wind, a touch, a smell.

2 · BRAIN

The real connectome runs for one second

Those sense neurons are stimulated in the 166,700-neuron brain, next to the same brain with nothing happening.

3 · BEHAVIOUR

Its neurons decide what it does

Escape neurons → jumped. Wing motor neurons → buzzed. Grooming, turning, walking, backing up.

4 · REPLY

Claude answers as that fly

Panic if it jumped, hype if it buzzed, nothing if the brain did nothing — and a brain log line proving it.

What the brain actually did (real runs)

You say	The fly senses	The brain did	Top neurons
"the boss wants the report by 5"	a huge shape looming	jumped, buzzed its wings	DNp04, DNp01, DNp02
"hi cutie"	another fly moving nearby	turned	DNg111, DNp17
"i brought pizza"	a taste	nothing — taste reaches the brain but moves no behaviour neurons	DNg48, DNg85
"what is 2 plus 2"	nothing a fly can sense	nothing	—

The word-to-sense table is hand-written and is the only made-up part. The reaction is the connectome's — which is why the pizza does nothing, however dramatic the fly wants to be.

How to integrate

Install in two minutes

Claude Code

Install the brainThe first run downloads ~260 MB of brain files.
Add the skillCopy the folder from the repo into your skills.
Talk to itSay "be a fly". Say "human mode" to stop.

pip install flybrain
git clone https://github.com/alextitonis/fly.ai
cp -r fly.ai/skills/fly-mode ~/.claude/skills/

Any agent or script

The skill is one Python script that prints JSON, so any agent framework, tool call or bot can use it.

python skills/fly-mode/scripts/fly_brain.py "someone brought pizza"
python skills/fly-mode/scripts/fly_brain.py --sense threat "anything"

{
 "sense": "threat",
 "felt": "a huge shape looming at it (looming detectors)",
 "did": ["jumped", "buzzed its wings"],
 "extra_spikes": {"escape": 89.3, "wings": 62.0, ...},
 "top_descending_neurons": [{"type": "DNp04", ...}],
 "brain": "MaleCNS v1.0 connectome, 166,700 neurons, ..."
}

Or build your own: the flybrain package

Everything above runs on flybrain, the whole fly nervous system as a spiking network you can stimulate and read out.

from flybrain import FlyBrain

brain = FlyBrain(sensory_input=False)          # downloads the brain files on first use
looming = brain.cells(["LC4", "LPLC2"])        # looming detectors
escape = set(brain.groups["escape_L"]) | set(brain.groups["escape_R"])

for step in range(75):                         # 1.5 s at 20 ms steps
    fired = brain.step(inject=[(looming, 0.8)] if step >= 25 else [])
    if escape & set(fired):
        print("the fly jumped at", step * 20, "ms")

How to use

Talking to the fly

In a chat

you:  be a fly
fly:  bzz. i am fly now. there is a lamp.

you:  the boss wants the report by 5
fly:  BOSS?? big shape. NOPE. *zooms to the ceiling*
      ...ok i'm back. flies don't do reports. bzz.
      🧠 felt: a huge shape looming at it · top neurons: DNp04, DNp01
         · did: jumped, buzzed its wings

you:  human mode
fly:  bzz. bye.

Good to know

It still helps. Ask a real question and the fly answers it, short and distracted.
It never fakes a reaction. If the brain did nothing, the fly does nothing. That's the joke, and it's true.
Brains are noisy. The same message can land a little differently each time; the script averages three runs.
Force a sense with --sense threat|taste|mate|wind|touch|smell when the words don't say it.
Runs locally on CPU (or GPU with flybrain[gpu]). Nothing is sent anywhere.

Skills on GitHub flybrain on PyPI llms.txt