Repository artifact retention

Kiln keeps reviewable evidence in Git and keeps raw execution output outside Git. The normative policy is contracts/repository-artifact-policy-v1.json, enforced by scripts/check_repository_artifacts.py on every push and pull request.

The policy governs what may enter the repository. It does not create a backup service or a time-based deletion job for local and external artifacts.

Choose where an artifact belongs

If a file is required to interpret a claim but is too large or too sensitive for Git, retain the file elsewhere and commit its exact SHA-256, byte count, role, and locator. A digest identifies bytes; it does not preserve them, authenticate their producer, or grant a reviewer access.

Retention boundary

Check in evidence that a reviewer can understand and validate without replaying an entire terminal session:

• Compact qualification and benchmark receipts with exact schema versions.
• Aggregate summaries, comparison tables, manifests, hashes, and verdicts.
• Hardware, model, workload, source-tree, and effective-configuration identity.
• Reproduction commands and the hash of any raw local artifact used to derive a conclusion.

Do not check in raw server logs, streamed SSE responses, Prometheus scrapes, profiler captures, traces, or large tabular exports. Local qualification writes these under ignored .qualification/ directories. Other experiments should use an equivalently ignored output directory and reduce their result to a compact receipt or summary before commit.

Review raw output for secrets and personal or customer data before copying it to any external store. Redaction changes file bytes, so record the digest of the retained, reviewed form rather than a discarded unredacted input.

Retention duration and deletion

The v1 contract sets no automatic expiry:

• Tracked compact evidence remains in the current tree until an ordinary reviewed change removes it. Its old bytes normally remain in Git history.
• Ignored .qualification/ output remains until the operator or host cleanup policy deletes it. Kiln does not prune it on a timer.
• External workflow or object-store artifacts follow that service’s configured retention period. The repository policy neither extends nor verifies it.
• Removing raw evidence after review preserves the committed digest and conclusion, but future reviewers can no longer recompute that digest unless another retained copy exists.

Before deleting raw evidence, decide whether future independent revalidation is required. If it is, move the exact bytes to controlled external storage, confirm the stored digest and byte count, and update the compact locator when the contract permits it. If it is not, document that the raw payload will no longer be available.

Deletion is deliberately not automated by scripts/check_repository_artifacts.py. The checker reports policy violations and can write a removal manifest, but a reviewer must choose what to archive or remove.

Enforced limits

The v1 policy applies to the exact Git index, not a filename list maintained by CI:

The suffix match is case-insensitive. The canonical list includes .log, .sse, .prom, .trace, .prof, .profile, .nsys-rep, .qdrep, .nvvp, and .perf.data. A file exactly at a byte limit is accepted; a file one byte over is rejected.

The general 10 MiB rule has a deliberately narrow exception mechanism. An exception must name one normalized repository path, exact byte count, exact content SHA-256, and a substantive rationale. Exceptions cannot authorize a forbidden raw-artifact suffix or a CSV over 1 MiB. Stale, moved, or content-drifted exceptions fail the check.

An exception permits one exact blob; it is not a directory pattern, suffix waiver, or standing size increase. The current v1 policy has no large-file exceptions.

Local check

Run the same check used by the lightweight hosted workflow:

python3 scripts/check_repository_artifacts.py

The checker reads NUL-delimited index records and Git object metadata, so spaces and newlines in tracked names cannot bypass it. It rejects unresolved index stages and validates exception content against the indexed blob.

The check evaluates the Git index. An untracked local file is outside this repository policy until someone stages it; other security and storage policies still apply.

Historical audit artifacts

The 2026-07-13 cleanup removed raw artifacts from the current tree without rewriting Git history. Compact audit summaries remain in docs/audits/ and docs/archive/. Their references to removed paths identify the original inputs; docs/audits/removed-raw-artifacts-2026-07-13-v1.json is the canonical lookup from each removed path to its byte count and SHA-256.

For a manifest entry with source_commit and path, restore a raw artifact to an ignored location with:

mkdir -p .qualification/restored
git show '<source_commit>:<path>' > .qualification/restored/artifact
sha256sum .qualification/restored/artifact

The observed digest must equal the manifest's sha256. This recovery path uses ordinary retained Git history. The cleanup did not run a history filter, force push, or garbage collection, so it reduces the current checkout and review surface but does not claim to reduce historical clone transfer size.

Recovery depends on the source commit still being reachable in the available repository history. A shallow clone or a future history rewrite may not contain it.

Creating a removal manifest

Before removing a previously tracked raw-artifact set, record its exact indexed content:

python3 scripts/check_repository_artifacts.py \
  --archive-current-offenders .qualification/removal-manifest.json

The command refuses to overwrite an existing manifest, refuses a dirty mismatch between each offender's worktree bytes and indexed blob, and records the source commit, policy hash, byte totals, per-reason counts, paths, and SHA-256 digests. Review the compact manifest, move it to an appropriate audit location, and only then remove the recorded files. No removal command is built into the checker.

The manifest proves which indexed bytes were selected for removal. It does not prove that an external archive exists; record external custody separately when the bytes must remain recoverable.

Failure triage

CI scope

.github/workflows/repository-hygiene.yml runs only checkout plus this Python check on an inexpensive CPU runner. It runs for every push and pull request so a large file with an unanticipated extension cannot evade path filters. It is a repository-integrity check, not hardware qualification and not evidence that a GPU backend works.