K4: an autoresearch loop for Kryptos

Can an autonomous research loop find the method behind Kryptos K4? An AI agent (Claude Code), following Karpathy's autoresearch pattern, attacks the unsolved fourth passage of Jim Sanborn's Kryptos sculpture at CIA headquarters: it designs one experiment at a time, pre-registers the hypothesis, runs it against a frozen harness, and keeps or reverts it. Every experiment, failed ones included, leaves a full record.

The results, live: alexisrondeau.me/k4: every experiment by outcome, the lineage of how each built on the last, the cipher families and what is still open, the pivots, the clue register and the lab notebook. The site and this repository are refreshed after every experiment.

Status

As of 2026-10-18: 198 experiments in 12 cipher families, 16 pivots. Not solved. No reading has beaten the same search run on scrambled copies of the carved text, so there is no champion. What the loop has produced so far is a map of bounded negative results: for each family, which settings were tested exactly and ruled out, which could not be decided from the 24 known letters, and why. The current numbers are on the site.

What success means

Decided 2026-10-14. A reproducible procedure that turns the 97-letter K4 ciphertext into 97 letters that:

1. contain EASTNORTHEAST at positions 22 to 34 and BERLINCLOCK at 64 to 74, exactly (position 1 is the O of OBKR);
2. read as English, allowing the one or two deliberate mistakes Sanborn puts in every section, and X as a separator;
3. re-encrypt to the exact sculpture ciphertext when the procedure is run forward;
4. come from a procedure a person could carry out by hand in 1990, written down step by step, keyed by something with a short description (key words, a named text and a place in it) rather than letters fitted to the known places.

Words without a method is not success. There is no external oracle: the loop certifies on these four criteria, the same standard that settled K1 to K3 before Sanborn confirmed anything. The verifier offered by the buyer of Sanborn's archive (2025) is not used.

How the loop works

• program.md is the agent's instruction set; tools/loop_prompt.md starts a run.
• attack.py is the only file an experiment changes. run_experiment.py is the frozen harness: it runs the attack under a 30-minute budget, scores every candidate, writes the record and commits it.
• kryptos/ holds the frozen facts, the cipher primitives (verified against K1 to K3 in tests/), the gates and the scorer.
• Two hard gates: a candidate that misses any of the 24 known letters fails before English is scored, and a reading must beat the same method run on scrambled copies of the carved text, so a search that makes English out of noise cannot win.
• Every experiment pre-registers its hypothesis, method and prediction, makes one focused change, and records its lineage (parent and what changed), an expert statement of the hypothesis and a plain-words walkthrough with a worked-example figure drawn from its own code.
• families.md and order-of-work.md are the living map of hypothesis families, their open items and the order of work; pivots/ records each change of family and why.
• knowledge/ is the distilled record: facts, the creators' statements, contradictions, the clue register and the assumptions register.

The record

Path	What
experiments/NNNN-slug/	one folder per experiment: experiment.md, attack.py as run, result.json, raw.json, the worked example
results.tsv, grades.tsv	the log, and each experiment's outcome against the scrambled copies
figures/	each experiment's worksheet and crib map
NOTEBOOK.md	the lab notebook, one entry per working day
reports/	longer research reports (prior attempts, success criteria, Scheidt's patents and field ciphers)
dashboard.py	the site: uv run python dashboard.py serves it locally; --export DIR writes it as static pages

Run it yourself

uv run --with pytest pytest -q      # the ruler must match K1-K3 before any run
uv run python run_experiment.py     # runs attack.py once, writes the record, commits it
uv run python dashboard.py          # the site at http://127.0.0.1:8765
tools/run_loop.sh                   # the loop, as its own Claude Code session

More in HUMANS.md.

What is not in this repository

This is the public copy of a private working repository, regenerated from it by tools/publish.py with these left out of every commit: the full texts of copyrighted articles and interviews in knowledge/sources/ (the index says where to read each original; the public-domain ones are included), the chat transcripts and agent logs, the raw research notes, design files, and the 3D model of the sculpture, which its author, Bret L Bowen, allows to be shared only as his own download. Issue numbers in the record refer to the private repository.

K4 ciphertext

OBKRUOXOGHULBSOLIFBBWFLRVQQPRNGKSSOTWTQSJQSSEKZZWATJKLUDIAWINFBNYPVTTMZFPKWGDKZXTJCDIGKUHUAUEKCAR

Four clues released by Sanborn: BERLIN (2010), CLOCK (2014), NORTHEAST (January 2020), EAST (August 2020).

Licence

GPL-3.0, as for the other autoresearch projects at alexisrondeau.me. The public-domain source texts remain in the public domain; the Wikipedia text is CC BY-SA 4.0.