Skip to content
Coding Standards
Blog

Preview Before You Commit: --dry-run and make diff-standards

C65 LLC

Phase 4 of the standards tooling roadmap adds two preview capabilities that let you see exactly what setup and sync-standards would change before a single file is modified.

The problem: trust during team rollouts

Section titled “The problem: trust during team rollouts”

When you run make setup or make sync-standards in an existing project, files get written. For a solo developer that is usually fine, but for a team rollout — or any project with carefully tuned AI agent configs — you want to review changes before committing to them. The new --dry-run flag and make diff-standards target solve this.

–dry-run for setup and sync

Section titled “–dry-run for setup and sync”

Both scripts/setup.sh and scripts/sync-standards.sh now accept a --dry-run flag. When active, no files are created, modified, or deleted. Instead, each write operation prints a [dry-run] line describing what would have happened.

$ ./scripts/setup.sh --dry-run


🔍 DRY RUN — showing what would change (no files modified)


📝 Assembling claude-code config...
  [dry-run] Would write: /project/CLAUDE.md
✅ claude-code config (dry-run)
📝 Assembling cursor config...
  [dry-run] Would write: /project/.cursorrules
✅ cursor config (dry-run)
  [dry-run] Would write: /project/.standards.yml
  [dry-run] Would write: /project/.git/hooks/post-merge
  [dry-run] Would append to: /project/.gitignore

Nothing was written. You can now review the list and decide whether to proceed.

The same flag works for sync:

$ ./scripts/sync-standards.sh --dry-run


🔍 DRY RUN — showing what would change (no files modified)


  [dry-run] Would pull latest standards (submodule has updates)
  [dry-run] Would re-assemble: /project/CLAUDE.md
  [dry-run] Would re-assemble: /project/.cursorrules
  [dry-run] Would create: /project/.gemini/GEMINI.md

make diff-standards: line-level preview

Section titled “make diff-standards: line-level preview”

--dry-run tells you which files would change. make diff-standards tells you exactly what would change inside each file. It assembles every declared agent config to a temp file, diffs it against the installed version, and prints color-coded output.

$ make diff-standards


Standards Diff
=======================================


→ claude-code  (CLAUDE.md)
  ~ Changes: +12/-3 lines
--- CLAUDE.md
+++ (assembled)
@@ -45,7 +45,7 @@
...


→ cursor  (.cursorrules)
  ✅ Up to date


→ copilot  (copilot-instructions.md)
  + Would create: .github/copilot-instructions.md


=======================================
  Summary: 1 up to date  1 would change  1 new


Run make sync-standards to apply changes.

No temp files are left behind. If everything is up to date you see only checkmarks.

Section titled “Recommended workflow for team rollouts”
  1. make diff-standards — review what would change across all agents
  2. ./scripts/sync-standards.sh --dry-run — confirm the list of write operations
  3. make sync-standards — apply once you are satisfied
  4. Commit the updated agent configs in a single PR for team review

This workflow is especially useful when pulling a new version of the standards submodule: diff first, sync second, never surprise your teammates.