Harness sync

Skill BCGen/skills/skills/harness-sync

Teach your coding agent — Claude Code, Cursor, or any AGENTS.md agent — your project's conventions, and turn every correction into a team-shared, git-tracked lesson.

Install

npx -y skills add BCGen/skills --skill harness-sync

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

2 stars2 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its author says it does

Copied from the file, not written here

Sets up and re-syncs a project's entry-file harness block — the wiring that brings retro in — plus cross-agent interop glue, with idempotent, diff-first, marker-managed writes; retro owns the learning loop. Use when setting up AI collaboration for a new or existing project, or when re-syncing the managed block after the skills were updated. Optional — projects bootstrap without it.

SKILL.md

4.0 KB, as published. Nobody here has run it

Harness Sync

Set up — and keep synced — the files agents read ("instruction surface") plus the harness loop. Tables and templates live in references/playbook.md — read it first. Never touch execution settings (settings.json, hooks, MCP, CI).

Step 1 — Detect

Check for agent artifacts (.claude/, CLAUDE.md, .cursor/, AGENTS.md) and coexisting frameworks (.specify/, .agent-os/, .kiro/steering/) per the playbook. Zero or multiple agents → ask one question with a recommended answer (AGENTS.md is the portable default). Never guess.

Step 2 — Inventory

List what already exists: entry file, harness block, interop glue. The plan covers the missing pieces AND the harness block if it drifted from the current template — re-running on an up-to-date project must be a no-op. The .ai/ loop directories are retro's to create; harness-sync neither creates nor reconciles them.

Step 3 — Discover (new entry file only)

If an entry file must be created, gather verified facts from the repo: build/test/lint commands read from manifests (package.json, Makefile, CI config), plus layout facts worth stating. Never write a command you did not verify in a file. Where the agent has a native bootstrap (e.g. /init), prefer it for discovery, then trim to the content policy: no generic rules, no personas, no best-practice boilerplate — verified facts and the harness block only.

Step 4 — Present the plan, then get approval

Print the full plan in the conversation — the complete content of every file to be created and a diff for every file to be modified — then ask for approval with the platform's option-prompt tool when it has one (Claude Code: AskUserQuestion) — choices like approve-as-planned / adjust-first; plain question only when no such tool exists. Never ask the user to approve content they have not seen. The plan covers:

Entry file (create, append the managed harness block to an existing one, or update a drifted block in place — never edit outside your harness:begin/end markers).
Interop glue when applicable (e.g. CLAUDE.md starting with @AGENTS.md).
No rules directory — git cannot track an empty directory; rule-writing creates it with the first rule.
No .ai/ loop directories — retro creates and maintains .ai/learnings/ and .ai/backlog/ on its first write; harness-sync only names them in the harness block.
Coexisting framework detected → one reference line instead of duplicate content, per the playbook.

Step 5 — Write and verify

Apply the approved plan, then self-check:

Re-run the inventory — everything present, nothing else changed.
User-authored content outside markers is byte-identical.
A hypothetical second run would change nothing (report this).

Step 6 — Report and hand off

Short summary: what was created/modified, the detected target, and the budget status (entry file lines / 60). Then point at the next move, in order:

Commit the new files — the harness is team-shared through git.
Existing project → run the codify skill next, so the agent's first real task already follows the project's conventions.
Then just work; retro picks up each task's lessons when it ends, creating .ai/learnings/ and .ai/backlog/ on its first write.

Mistakes to refuse

Request	Response
"Also set up permissions/hooks/MCP"	Out of scope — instruction surface only
"Generate a full set of best-practice rules"	Near-empty baseline by design; rules come from evidence via rule-writing
"Rewrite my existing CLAUDE.md"	Only the managed block is yours to write