--- license: cc-by-4.0 pretty_name: AtlasOpenCoder --- # AtlasOpenCoder — v1.0 Calibrated concept profiles for **OpenCoder-1.5B-Base**, read on 169 Python constructs across 61 pretraining and annealing checkpoints. This dataset is the battery, the licence tables and the artefacts every figure and table of two papers reads: * **"Calibrated Concept Profiles: Making the Reading of a Model's Neurons a Measurement"** (Wilam, 2026) — the method. Its code: `piotrwilam/AtlasCalibratedConceptProfiles`. * **"Representational Drift in a Code Model: Behaviour Settles, Which Neurons Carry It Does Not"** (Wilam, 2026) — the finding, read with that instrument on this dataset. Its code: `piotrwilam/AtlasRepresentationalDrift`. `MANIFEST_PAPER1.md` and `MANIFEST_PAPER2.md` below are named for the first and the second of those, in that order. ## What is here | | | |---|---| | `phase_battery/` | the battery: 557,990 prompts in sets A, B and C, two twins and the nu arm | | `battery/` | the earlier pilot battery | | `validation/` | every artefact a figure or table in either paper reads | | `inventory/`, `calibration/` | the 206 constructs and the corpus rate tables | | `probe/companions.json` | the logged companion shares | | `MANIFEST_PAPER1.md`, `MANIFEST_PAPER2.md` | every number in each paper, to its file, field and script | **The battery cannot be regenerated.** Its per-prompt seeds came from `abs(hash(...))`, salted per process, so the seeds recorded in `CONTENT_HASHES.json` do not reproduce the prompts they name. That is why it is published. ## What is not here **The raw record (2,022 GB over 61 references)** — per-core accumulators and per-prompt activations. It is regenerable from OpenCoder's released checkpoints, this battery and the code. One reference of it is planned for the next version. **The pilot recording.** Two artefacts were once computed from a pilot tree and later found to differ from the phase recording at every reference; everything derived from it is excluded and named in the papers. ## Two batteries, two hashes The **recorded** battery — the one the model was run on, and the one the papers' numbers come from — carries prompt-content hash `570b42db…`, and its per-set hashes are the figures the papers cite. The **released** battery differs from it in **1,927 of 557,990 prompts (0.35%)**: those prompts drew padding containing one of six third-party email addresses, which are replaced here with `user@example.com`. The token offsets each prompt stores are recomputed to match, and the recomputation is verified per prompt. See `phase_battery/REDACTION.json` and `phase_battery/RELEASED_HASHES.json`. Only a reader who re-runs the model on those 1,927 prompts sees a difference. Every artefact in `validation/` was computed on the recorded battery. ## Licence The dataset's own content (generator text, profiles, tables, artefacts) is **CC BY 4.0** (`LICENSE`); the padding snippets in the battery remain under their original licences, listed in `ATTRIBUTION.md`. **The padding is not ours.** Padding blocks were drawn from `codeparrot/codeparrot-clean` and carry the licences of the repositories they came from: MIT, Apache-2.0, BSD, GPL, AGPL, LGPL and others. Roughly **29% of prompts** contain at least one such fragment, each one to three lines and a median of 45 characters. Every block, its source repositories and their licences are listed in `ATTRIBUTION.md`. ## Citing Cite **the paper that owns this dataset, and the DOI together with the tag** — the method paper, named above. The dataset is its instrument and its realisation on OpenCoder; the second paper reads it. > Wilam, P. (2026). *Calibrated Concept Profiles: Making the Reading of a Model's Neurons a > Measurement.* Dataset: AtlasOpenCoder, tag `v1`. **The DOI is shown on this page, above the file list, and belongs in the citation beside the tag.** It is not repeated here: a DOI names the revision it was minted on, so a card cannot carry its own without pointing at a later revision than the one the DOI names. The paper's arXiv identifier is in the paper's own listing. A Hugging Face DOI is assigned **to the revision it is generated on**, so a later version takes a new DOI and the earlier one is marked outdated. Name the tag as well as the DOI: the tag says which content a number came from in words a reader can check against this repository's history. **Version 1 is the 20-cell yardstick** (4 token classes x 5 fifths of the prompt). A later version computed under a different yardstick names different neurons for the same constructs, so a figure from one version cannot be compared with a figure from another. ## What the directory names mean `validation/paper1/` and `validation/paper2/` record **which paper's script wrote a file, not which paper reads it**. Both papers read across them: the first paper's numbers come from 31 files under `validation/paper2/` and `validation/r2/`, and the second paper's from 14 under `validation/paper1/`. `MANIFEST_PAPER1.md` and `MANIFEST_PAPER2.md` in this repository give, for every number printed in each paper, the file and the field it is read from and the script that rebuilds that file -- 407 numbers and 495, including the few that no released file holds, which are marked and collected in a section of their own. ## Provenance The model is `OpenCoder-LLM/OpenCoder-1.5B-Base-Checkpoints` (MIT). The reference corpus is `codeparrot/codeparrot-clean`. The yardstick is the 20-cell split (4 token classes × 5 fifths of the prompt), version 1.