divisor-entropy agent — structural delta enforcement

[jflowers]

Summary

Create a divisor-entropy.md agent that computes the structural delta between base and PR branches, enforcing the Boy Scout Rule ("leave the code better than you found it"). Deployed to consuming projects via vibe-check init.

RFC: https://github.com/orgs/unbound-force/discussions/483 — Group 2a
Phase: P1 (Enforcement)

Context

The Review Council currently has 9 divisor-* agents that are dynamically discovered. This adds a new entropy-focused divisor that ensures PRs do not degrade structural quality metrics. The agent is shipped as an embedded asset in the vibe-check binary and deployed via vibe-check init (analogous to gaze init).

Deployment

vibe-check init
  └── deploys .opencode/agents/divisor-entropy.md

The agent file lives in internal/scaffold/assets/agents/divisor-entropy.md within the vibe-check repo and is embedded via //go:embed.

Agent Design

divisor-entropy.md

• Discovery: Auto-discovered by the Review Council (follows existing divisor-* naming convention)
• Role: Computes structural quality delta between the base branch and the PR branch
• Tooling: Calls vibe-check analyze on both base and PR branches to compute deltas

What It Measures

• Package coupling changes (Ca, Ce, Instability delta)
• New circular dependencies introduced
• Cohesion changes (LCOM delta)
• Overall structural entropy direction (improving / stable / degrading)

Verdict Logic

• APPROVE: Structural metrics improve or remain stable
• REQUEST CHANGES: PR introduces new circular deps, significantly increases instability, or degrades cohesion beyond threshold
• COMMENT: Minor metric shifts that warrant discussion

Acceptance Criteria

• divisor-entropy.md agent created in internal/scaffold/assets/agents/
• Deployed to .opencode/agents/ via vibe-check init
• Auto-discovered by Review Council (follows naming convention)
• Calls vibe-check analyze (not gaze, not goda) on both branches
• Computes structural delta between base and PR branches
• Provides clear verdict (APPROVE / REQUEST CHANGES / COMMENT) with metric justification
• Tested with sample PRs showing improvement and degradation

Dependencies

• Depends on: vibe-check analyze — Go-native package-level coupling metrics #2 — vibe-check analyze command (for metric collection)

[jflowers]

closed by #26