"""
Karpathy Autoresearch Loop + TensorLake Sandboxes
==================================================
Inspired by github.com/karpathy/autoresearch (April 2026, 64k⭐).
The "Karpathy Loop":
1. Give an AI agent a training script and a plain-English program.md
2. Agent proposes one targeted code modification per iteration
3. Run the modified script in isolation for a fixed step budget
4. If val_loss improves → accept, update the baseline
5. Repeat overnight → hundreds of validated improvements
TensorLake sandboxes are the right tool here:
• Modified training code is untrusted (the agent could emit anything)
• Multiple candidate modifications can race in parallel sandboxes
• Each sandbox is killed after the time budget: no runaway experiments
• The host process never imports/executes model weights or agent code
This example:
State : current best train.py + full experiment history
Action : LLM proposes one self-contained code modification
Sandbox : TensorLake runs the modified script for STEPS training steps
Reward : Δval_loss = best_val_loss − new_val_loss (positive = improvement)
Update : Greedy hill-climbing (accept if reward > 0)
Parallelism: CANDIDATES sandboxes race each iteration (ThreadPoolExecutor)
Smoke : --smoke → 3 iters, 2 candidates, 150 steps/run (~5 min)
Full : 8 iters, 3 candidates, 300 steps/run (~20 min)
"""
from dotenv import load_dotenv
load_dotenv()
import re
import sys
import time
from dataclasses import dataclass, field
from typing import List, Optional
from openai import OpenAI
from tensorlake.sandbox import Sandbox
from tensorlake.applications import application, function
from rich.console import Console
from rich.panel import Panel
from rich.table import Table
from rich.rule import Rule
from rich import box
console = Console()
SMOKE = "--smoke" in sys.argv
# ─── program.md: plain-English guidance for the agent ───────────────────────
# This is what Karpathy calls "the human's job": describe the search space.
PROGRAM_GUIDANCE = """\
You are an ML research agent optimising a character-level MLP language model
trained on a small text corpus using numpy only (no torch/tensorflow).
The training script defines these tunable constants near the top:
CTX (context window / n-gram size, int)
HIDDEN (hidden layer size, int)
LR (learning rate, float)
BATCH (batch size, int)
WDECAY (L2 weight decay, float)
STEPS (DO NOT CHANGE - fixed budget)
Good things to try:
• Learning rate: sweep 1e-4 → 0.1
• Learning rate decay: multiply LR by 0.999 each step (add near opt.step)
• Hidden size: 32 / 64 / 128 / 256
• Context window CTX: 2 / 4 / 8
• Weight decay WDECAY: 0 → 1e-4
• Activation: replace np.tanh with np.maximum(0, x) (ReLU) or np.clip(x,0,None)
• Initialization scale: change 0.01 to 0.1 or use He/Xavier init
• Add a second hidden layer (W3, b3) with size HIDDEN//2
• Momentum: track velocity vectors, apply SGD+momentum
• Batch size: 16 / 32 / 64
Constraints:
• numpy only: do not import torch, tensorflow, sklearn
• STEPS must stay unchanged
• Output format: last printed line must be val_loss: X.XXXX
"""
# ─── Baseline training script ─────────────────────────────────────────────────
# ~130 K-param nano-GPT on a small public-domain text.
# Runs in ~15 s on CPU (150 steps) / ~30 s (300 steps).
BASELINE_SCRIPT = '''\
import subprocess, sys
subprocess.run(["python3","-m","pip","install","numpy","-q","--target","/tmp/pkgs"],
capture_output=True, check=False)
sys.path.insert(0, "/tmp/pkgs")
import numpy as np
np.random.seed(42)
# ── Corpus (opening of Alice in Wonderland, public domain) ──────────────────
TEXT = (
"Alice was beginning to get very tired of sitting by her sister on the bank,"
" and of having nothing to do: once or twice she had peeped into the book her"
" sister was reading, but it had no pictures or conversations in it, and what"
" is the use of a book thought Alice without pictures or conversations so she"
" was considering in her own mind as well as she could for the hot day made"
" her feel very sleepy and stupid whether the pleasure of making a daisy-chain"
" would be worth the trouble of getting up and picking the daisies when"
" suddenly a White Rabbit with pink eyes ran close by her there was nothing so"
" very remarkable in that nor did Alice think it so very much out of the way"
" to hear the Rabbit say to itself oh dear oh dear I shall be late when she"
" thought it over afterwards it occurred to her that she ought to have wondered"
" at this but at the time it all seemed quite natural but when the Rabbit"
" actually took a watch out of its waistcoat-pocket and looked at it and then"
" hurried on Alice started to her feet for it flashed across her mind that she"
" had never before seen a rabbit with either a waistcoat-pocket or a watch to"
" take out of it and burning with curiosity she ran across the field after it"
) * 4 # ~4 800 chars
# ── Tokeniser ────────────────────────────────────────────────────────────────
chars = sorted(set(TEXT))
vocab = len(chars)
stoi = {c: i for i, c in enumerate(chars)}
data = [stoi[c] for c in TEXT]
split = int(0.9 * len(data))
train_d, val_d = data[:split], data[split:]
# ── Hyperparameters (agent modifies these) ───────────────────────────────────
CTX = 4 # context window (n-gram)
HIDDEN = 64 # hidden layer size
LR = 0.05 # learning rate
BATCH = 32 # mini-batch size
WDECAY = 0.0 # L2 weight decay
STEPS = STEPS_PLACEHOLDER # fixed budget - do not change
# ── Parameters ───────────────────────────────────────────────────────────────
W1 = np.random.randn(vocab * CTX, HIDDEN) * 0.01
b1 = np.zeros(HIDDEN)
W2 = np.random.randn(HIDDEN, vocab) * 0.01
b2 = np.zeros(vocab)
def get_batch(d):
idx = np.random.randint(0, len(d) - CTX, BATCH)
X = np.zeros((BATCH, vocab * CTX))
for i, start in enumerate(idx):
for j in range(CTX):
X[i, j * vocab + d[start + j]] = 1.0
Y = np.array([d[i + CTX] for i in idx])
return X, Y
def forward(X):
H = np.tanh(X @ W1 + b1)
logits = H @ W2 + b2
logits -= logits.max(1, keepdims=True)
probs = np.exp(logits)
probs /= probs.sum(1, keepdims=True)
return H, probs
def ce_loss(probs, Y):
return -np.log(probs[np.arange(len(Y)), Y] + 1e-8).mean()
# ── Training loop ─────────────────────────────────────────────────────────────
for step in range(STEPS):
X, Y = get_batch(train_d)
H, probs = forward(X)
dl = probs.copy(); dl[np.arange(BATCH), Y] -= 1; dl /= BATCH
dW2 = H.T @ dl; db2 = dl.sum(0)
dH = dl @ W2.T * (1 - H**2)
dW1 = X.T @ dH; db1 = dH.sum(0)
W1 -= LR * (dW1 + WDECAY * W1)
b1 -= LR * db1
W2 -= LR * (dW2 + WDECAY * W2)
b2 -= LR * db2
# ── Evaluate ──────────────────────────────────────────────────────────────────
losses = [ce_loss(forward(get_batch(val_d)[0])[1], get_batch(val_d)[1]) for _ in range(30)]
print(f"val_loss: {np.mean(losses):.4f}")
'''
# ─── Data models ──────────────────────────────────────────────────────────────
@dataclass
class Experiment:
iteration: int
candidate: int
description: str
script: str
val_loss: Optional[float] = None
delta: Optional[float] = None # positive = improvement
accepted: bool = False
error: Optional[str] = None
@dataclass
class ResearchState:
best_script: str
best_val_loss: float = 999.0
history: List[Experiment] = field(default_factory=list)
def history_summary(self) -> str:
if not self.history:
return "No experiments yet."
lines = []
for e in self.history[-8:]: # last 8
status = "✓ ACCEPTED" if e.accepted else ("✗ error" if e.error else "✗ rejected")
vl = f"{e.val_loss:.4f}" if e.val_loss else "—"
d = f"Δ{e.delta:+.4f}" if e.delta is not None else ""
lines.append(f" [{status}] iter={e.iteration} val={vl} {d} - {e.description}")
return "\n".join(lines)
# ─── Agent: propose one code modification ────────────────────────────────────
def propose_modification(state: ResearchState, candidate_idx: int) -> tuple[str, str]:
"""Returns (description, modified_script)."""
client = OpenAI()
prompt = f"""{PROGRAM_GUIDANCE}
Current best val_loss: {state.best_val_loss:.4f}
Experiment history:
{state.history_summary()}
Current best script:
```python
{state.best_script}
```
Propose modification #{candidate_idx + 1} (make it different from recent attempts).
Return ONLY a JSON object with two keys:
"description": one sentence describing the change
"script": the complete modified Python script
No markdown fences around the JSON. Just the raw JSON object."""
resp = client.chat.completions.create(
model="gpt-4o",
messages=[{"role": "user", "content": prompt}],
temperature=0.9 + candidate_idx * 0.1, # more exploration for later candidates
response_format={"type": "json_object"},
)
import json
data = json.loads(resp.choices[0].message.content)
return data["description"], data["script"]
# ─── TensorLake @function for map-reduce ──────────────────────────────────────────
@function()
def run_experiment_in_sandbox(exp_data: dict) -> dict:
"""Run exp.script in a TensorLake sandbox via map-reduce."""
import re
iteration = exp_data["iteration"]
candidate = exp_data["candidate"]
description = exp_data["description"]
script = exp_data["script"]
max_retries = 5
last_error = None
for attempt in range(max_retries):
try:
box = Sandbox.create(memory_mb=4096, timeout_secs=900)
ex = box.run("python3", ["-c", script], timeout=300)
stdout = (ex.stdout or "").strip()
stderr = (ex.stderr or "").strip()
m = re.search(r"val_loss:\s*([0-9.]+)", stdout)
if not m:
return {
"iteration": iteration,
"candidate": candidate,
"description": description,
"val_loss": None,
"error": (stderr or stdout)[:120] or "no val_loss in output"
}
return {
"iteration": iteration,
"candidate": candidate,
"description": description,
"val_loss": float(m.group(1)),
"error": None
}
except Exception as exc:
last_error = str(exc)[:150]
if attempt < max_retries - 1:
wait_time = 2 ** attempt
time.sleep(wait_time)
continue
return {
"iteration": iteration,
"candidate": candidate,
"description": description,
"val_loss": None,
"error": last_error
}
return {
"iteration": iteration,
"candidate": candidate,
"description": description,
"val_loss": None,
"error": last_error
}
# ─── Main autoresearch loop (TensorLake @application) ──────────────────────────────
@application()
@function()
def autoresearch(iterations: int = 8, candidates: int = 3):
steps = 150 if SMOKE else 300
console.print(Panel(
"[bold cyan]Karpathy Autoresearch Loop + TensorLake Map-Reduce[/bold cyan]\n\n"
"[dim]Inspired by github.com/karpathy/autoresearch (April 2026)\n\n"
"Loop:\n"
" 1. Agent reads current best script + experiment history\n"
" 2. Proposes CANDIDATES modifications (different temperatures)\n"
" 3. All CANDIDATES run in parallel via Tensorlake map-reduce\n"
" 4. Best val_loss wins; accepted if it beats the current best\n"
" 5. Accepted script becomes the new baseline\n\n"
"Reward = Δval_loss (positive = improvement)\n"
"Policy = GPT-4o prompted with program.md + experiment history\n"
"Update = greedy hill-climbing (accept if reward > 0)\n"
f"Mode = {'SMOKE (3 iters, 2 candidates, 150 steps)' if SMOKE else f'Full ({iterations} iters, {candidates} candidates, {steps} steps)'}[/dim]",
border_style="cyan",
))
# ── Calibrate baseline ───────────────────────────────────────────────────
baseline = BASELINE_SCRIPT.replace("STEPS_PLACEHOLDER", str(steps))
console.print(Rule("[yellow]Calibrating baseline[/yellow]", style="yellow"))
console.print("[dim]Running baseline script in sandbox to establish starting val_loss...[/dim]")
calib_result = run_experiment_in_sandbox({
"iteration": 0,
"candidate": 0,
"description": "baseline",
"script": baseline
})
if calib_result["error"] or calib_result["val_loss"] is None:
console.print(f"[red]Baseline failed: {calib_result['error']}[/red]")
return
calib_val_loss = calib_result["val_loss"]
state = ResearchState(best_script=baseline, best_val_loss=calib_val_loss)
console.print(f" Baseline val_loss: [bold yellow]{state.best_val_loss:.4f}[/bold yellow]\n")
try:
# ── Research iterations ──────────────────────────────────────────────────
for it in range(1, iterations + 1):
console.print(Rule(f"[cyan]Iteration {it}/{iterations}[/cyan]", style="cyan"))
console.print(f" [dim]Current best: {state.best_val_loss:.4f} "
f"Proposing {candidates} candidates (map-reduce)...[/dim]")
# Propose candidates (sequentially, they call the LLM)
proposals_data = []
for c in range(candidates):
desc, script = propose_modification(state, c)
proposals_data.append({
"iteration": it,
"candidate": c,
"description": desc,
"script": script
})
# Run all candidates in parallel using Tensorlake map-reduce
console.print(f" [dim]Executing {candidates} candidates in parallel (Tensorlake map-reduce)...[/dim]")
result_dicts = run_experiment_in_sandbox.map(proposals_data)
results = []
for res in result_dicts:
exp = Experiment(
iteration=res["iteration"],
candidate=res["candidate"],
description=res["description"],
script=proposals_data[res["candidate"]]["script"],
val_loss=res["val_loss"],
error=res["error"]
)
results.append(exp)
# Score & rank
valid = [r for r in results if r.val_loss is not None]
for r in valid:
r.delta = state.best_val_loss - r.val_loss # positive = improvement
valid.sort(key=lambda r: r.val_loss)
# Print iteration table
t = Table(box=box.SIMPLE, show_header=True, header_style="bold white")
t.add_column("C", width=3)
t.add_column("Modification", width=52)
t.add_column("val_loss", width=9, justify="right")
t.add_column("Δ", width=9, justify="right")
t.add_column("", width=3)
for r in sorted(results, key=lambda r: (r.val_loss or 999)):
if r.error:
t.add_row(str(r.candidate), r.description[:50], "—", "—",
f"[red]✗[/red]")
continue
delta_str = (f"[green]{r.delta:+.4f}[/green]" if r.delta and r.delta > 0
else f"[red]{r.delta:+.4f}[/red]" if r.delta
else "—")
t.add_row(str(r.candidate), r.description[:50],
f"{r.val_loss:.4f}", delta_str, "")
console.print(t)
# Accept best if improved
if valid and valid[0].delta is not None and valid[0].delta > 0:
winner = valid[0]
winner.accepted = True
state.best_val_loss = winner.val_loss
state.best_script = winner.script
console.print(
f" [bold green]✓ Accepted: {winner.description}\n"
f" val_loss {calib_val_loss:.4f} → {state.best_val_loss:.4f} "
f"(Δ{winner.delta:+.4f})[/bold green]"
)
else:
console.print(" [dim]No improvement this iteration; baseline unchanged.[/dim]")
state.history.extend(results)
# ── Final summary ────────────────────────────────────────────────────────
finally:
accepted = [e for e in state.history if e.accepted]
total_improvement = calib_val_loss - state.best_val_loss
pct = total_improvement / calib_val_loss * 100
color = "bold green" if pct > 5 else "yellow" if pct > 0 else "red"
console.print(Panel(
f"[bold green]Autoresearch complete[/bold green]\n\n"
f"Baseline val_loss : [yellow]{calib_val_loss:.4f}[/yellow]\n"
f"Final val_loss : [bold green]{state.best_val_loss:.4f}[/bold green]\n"
f"Total improvement : [{color}]{total_improvement:+.4f} ({pct:+.1f}%)[/{color}]\n"
f"Accepted changes : {len(accepted)} / {len(state.history)}\n\n"
+ ("\n".join(f" ✓ iter {e.iteration}: {e.description}" for e in accepted)
if accepted else " (none)"),
title="[bold]Research Summary[/bold]",
border_style="green",
))
# ── Result interpretation ─────────────────────────────────────────────────
accept_rate = len(accepted) / len(state.history) * 100 if state.history else 0
console.print(Panel(
f"[bold]What these numbers mean[/bold]\n\n"
f"val_loss is cross-entropy on held-out characters (nats).\n"
f"Lower = the model assigns higher probability to the correct next character.\n\n"
f" Baseline {calib_val_loss:.4f} → Final {state.best_val_loss:.4f} "
f"([{color}]{pct:+.1f}%[/{color}])\n\n"
f"Context:\n"
f" • A random character predictor on this ~50-char vocabulary scores ln(50) ≈ 3.91\n"
f" • The baseline MLP ({calib_val_loss:.2f}) already beats random: it learned\n"
f" that 'e', space, and 't' are far more likely than 'Z'\n"
f" • Each accepted change is a genuine algorithmic improvement:\n"
f" the agent modified real training code and the sandbox verified it\n"
f" on held-out data, not on the training set\n\n"
f"Acceptance rate: {len(accepted)}/{len(state.history)} ({accept_rate:.0f}%)\n"
f" • Typical for greedy hill-climbing on a small model: 25–40% is normal\n"
f" • Rejected experiments are still informative: they update the agent's\n"
f" memory so it avoids the same dead ends next iteration\n\n"
f"Smoke vs full run:\n"
f" • Smoke (3 iters, 2 candidates, 150 steps) is a proof-of-concept\n"
f" • Full run (8 iters, 3 candidates, 300 steps) gives the agent\n"
f" enough budget to explore LR schedules, second layers, momentum,\n"
f" and architecture changes; improvements compound across iterations\n"
f" • Karpathy's original loop ran ~700 experiments overnight and found\n"
f" 11% speed improvement; the same pattern scales here",
title="[bold cyan]Score interpretation[/bold cyan]",
border_style="cyan",
))
if accepted:
console.print(Rule("[green]Final best script[/green]", style="green"))
console.print(Panel(state.best_script[:1200] + ("..." if len(state.best_script) > 1200 else ""),
border_style="green"))
if __name__ == "__main__":
from tensorlake.applications import run_local_application, Request
request: Request = run_local_application(
autoresearch,
iterations=3 if SMOKE else 8,
candidates=2 if SMOKE else 3,
)
