Summary

• Homebrew formula now installs from tar archives (not bare binaries), placing the Sigstore attestation bundle next to the binary in bin/ so aicr can find it at <binary>-attestation.sigstore.json
• Optional cosign verification on install — if cosign is present, the formula verifies binary provenance against the SLSA attestation bundle before completing
• Runs aicr trust update post-install to fetch the latest Sigstore trusted root (fails gracefully with a warning if sandboxed or offline)
• Added syft to dev tooling — .settings.yaml, setup-tools, and check-tools now include syft (SBOM generator required by goreleaser)
• Bumped tilt from 0.36.3 to 0.37.0

Changed Files

How It Works

# 1. Install binary and attestation bundle next to it
bin.install "aicr"
bin.install "aicr-attestation.sigstore.json"

# 2. Verify provenance if cosign is available
if File.exist?(bin/"aicr-attestation.sigstore.json") && which("cosign")
  system "cosign", "verify-blob-attestation", ...
end

# 3. Update Sigstore trusted root (graceful fallback)
system(bin/"aicr", "trust", "update") rescue opoo("...")

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)
• Build/CI/tooling

Testing

Local testing, but might require a some round of testing in CI yet.

• goreleaser release --snapshot --clean --skip=publish generates correct formula
• ruby -c dist/homebrew/Formula/aicr.rb passes syntax check
• Local tap install succeeds (brew install local/aicr/aicr)
• Post-install trust update fails gracefully in Homebrew sandbox
• Attestation bundle skipped correctly when not present (snapshot builds)
• make tools-check shows syft with correct version
• Verified syft Linux download URLs return 302 (amd64 + arm64)
• Tested setup-tools on Linux — syft installs correctly with updated .settings.yaml
• TODO: Full release build verifies cosign attestation path (requires CI tag build)

Risk Assessment

• Low — Isolated change, well-tested, easy to revert
• Medium — Touches multiple components or has broader impact
• High — Breaking change, affects critical paths, or complex rollout

Rollout notes:

Checklist

• Tests pass locally (make test with -race)
• Linter passes (make lint)
• I did not skip/disable tests to make CI green
• I added/updated tests for new functionality
• I updated docs if user-facing behavior changed
• Changes follow existing patterns in the codebase
• Commits are cryptographically signed (git commit -S) — GPG signing info