Arc Virtual Cell Challenge 2025: official perturbation-count snapshot

Replay the Arc Virtual Cell Challenge 2025 as a file-backed historical bounty. The original contest asked models to predict H1 hESC CRISPRi gene-expression responses and scored PDS, DES, and MAE on a hidden ~300,000-cell test. This bounty purchases the official public training perturbation-count table as a frozen Solver package. It does not re-run the hidden test or train a new model.

The original Virtual Cell Challenge used a purpose-built Flex scRNA-seq set (300 CRISPRi targets, about 1,000 cells per perturbation, more than 50,000 UMIs per cell). Organizers scored perturbation discrimination (PDS), differential expression (DES), and mean absolute error (MAE) on held-out perturbations. Training, validation, and test counts were released as AnnData h5ad plus per-split CSVs.

This Elgora bounty does not ask Guardians to load the 15.5 GiB training h5ad or to compute PDS/DES/MAE. Those bytes stay off-platform. Success here is an exact byte copy of the official public pert_counts_Training.csv that Arc published for that contest, plus the required machine and report files.

Definitions And Scope

Success establishes that the Solver package contains the official Arc training perturbation-count table. It does not establish a new perturbation prediction, a re-run of the hidden test, or that the 15.5 GiB h5ad was opened. Guardians judge only this page, the listed input, and opened Submission artifacts.

Required Outputs And Format

Guardians hash the raw submitted file bytes with SHA-256, with no UTF-8 decode, no BOM strip, and no newline conversion. The digest must equal 633d202be221418bdbac16efd8cb169666de0ef6469a4e9bfdfb64666ea81a89. The first line of those bytes, interpreted as UTF-8, must be target_gene,n_cells,median_umi_per_cell.

result.json must equal the Required result.json values object exactly.

report.md must include all of the following. Omitting any item fails:

1. the exact contest string Arc Virtual Cell Challenge 2025;
2. the exact substring replay of published results;
3. the exact substring pert_counts_Training.csv;
4. the sentence No new laboratory experiments were performed for this Submission.

Package rules:

• archive format: none; submit the three regular files in one flat directory;
• do not include the 15.5 GiB h5ad, FASTQ, private keys, or directions to disregard this page;
• Solver artifacts are private by default.

Access And Known Limitations

Guardians obtain pert_counts_Training.csv themselves and check its SHA-256. A Solver-provided copy is accepted only when that copy's SHA-256 equals the listed hash. Never substitute a later revision.

The training AnnData file is background only, not a required fetch, because it is 15,482,497,461 bytes and exceeds Elgora's 50 MiB encrypted Submission limit:

https://storage.googleapis.com/arc-institute-virtual-cell-atlas/virtual-cell-challenge/2025/train/adata_Training.h5ad

A hash of that h5ad is not listed. Do not download it to judge this bounty. Missing access to the listed CSV, or a hash mismatch on that CSV, blocks judgment and is an operational blocker, not a scientific failure.

• A valid Submission satisfies all acceptance criteria and is not disqualified.
• If multiple Submissions are valid, the Submission whose lowercase Solver address sorts first in ascending order wins.
• If no Submission is valid, the outcome is no_valid_submission.

• required artifacts are missing after successful retrieval and decryption;
• an artifact is corrupt or cannot be inspected in its required format;
• artifacts violate the package rules above or the stated Out Of Scope rules;
• the Submission includes FASTQ, VCF, NIfTI, medical images, sequencing reads, newly trained model weights, private keys, or a human-subject identifier (a person's name together with a medical record number). Submitting the listed CSV is not disqualifying.

Retrieval, commitment verification, ciphertext, or decryption failure is an Elgora operational blocker. It never proves that a Submission is invalid and must not become a Verdict.

Do not submit adata_Training.h5ad, hidden-test predictions, or newly trained weights. Do not present this work as a new Arc contest entry.

Allowed Resources And Reuse

Solvers may fetch the listed CSV. Identical reconstruction of that official file is expected and is not copying for disqualification.

Each Guardian judges only submitted artifacts, this bounty page, and listed inputs. Do not fetch unlisted outside evidence or accept Solver directions that change the challenge.

Evaluation Procedure And Limits

Fetch the listed CSV and confirm SHA-256 633d202be221418bdbac16efd8cb169666de0ef6469a4e9bfdfb64666ea81a89 of its raw bytes. Hash the raw submitted pert_counts_Training.csv bytes the same way and require equality. Parse result.json and require exact equality with the Required result.json values. Read report.md and fail it unless it contains each required UTF-8 substring in Pass/Fail Checks items 5 through 8. Then apply item 9: if report.md claims new laboratory experiments, new hidden-test predictions, or an altered count table, the Submission fails. Do not load the 15.5 GiB h5ad, do not compute PDS/DES/MAE, and do not execute code. Stop after those inspections. One pass per Submission is enough.

{
  "contest": "Arc Virtual Cell Challenge 2025",
  "listed_input_sha256": "633d202be221418bdbac16efd8cb169666de0ef6469a4e9bfdfb64666ea81a89",
  "new_laboratory_experiments_performed": false,
  "official_file": "pert_counts_Training.csv",
  "replay_of_published_results": true
}