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Chachamaru
via GitHub · Posted Jul 12, 2026 · 1 min read
Claude Skill

Claude Code Dedicated Development Harness - Achieving High-Quality Development Through an Autonomous Plan→Work→Review Cycle

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A structured development framework that orchestrates Claude Code through repeatable planning, implementation, review, and release phases with machine-checked specifications and CI gates. Designed for teams and individual developers who want autonomous AI-assisted coding with verifiable output and clear decision surfaces at each stage.

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README

Claude Code Harness

Claude Code is powerful, but raw agent work drifts: plans live in chat, tests become optional, review happens too late, and release evidence gets rebuilt by memory. Harness turns that into one repeatable operating path.

After install, the default changes from "ask the agent to code" to:

  1. write the spec and plan,
  2. implement only the approved slice,
  3. verify the result,
  4. review independently,
  5. package evidence for PR or release.

Claims in this README are machine-checked against the code. CI gates verify that implemented components are actually wired (no dead code claimed as done), that the task ledger's dependencies stay consistent, and that the shipped binaries rebuild from source. A feature is described here only after a gate proves it is reachable — "written" is not "working."

Quickstart

New users should start from the tool they already use. Existing users should run the migration report before cleanup or reinstall.

Path Start
New user Tool-first onboarding
Existing user Migration check
Claude Code fast path Install in 30 seconds
Trigger proof Skill trigger gate

Install in 30 Seconds

claude
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install claude-code-harness@claude-code-harness-marketplace
/harness-setup

Next command: run /harness-plan with one small request.

/harness-plan Improve the README onboarding flow

First 15 Minutes

  1. Install through your tool route.
  2. Run /harness-setup or the equivalent setup script.
  3. Run /harness-plan with a small request; Harness writes the spec.md and Plans.md drafts for you to check. Small typo, docs, and status updates stay lightweight.
  4. Approve the generated contract or reply with the correction you want.
  5. Run the smallest approved task, for example /harness-work 1.1.1.
  6. Run /harness-review and keep the verification output.

Your job is not to hand-write the plan. It is to approve or correct the generated contract before execution continues.

How It Works

Harness adds a source-of-truth loop around agent work. The 5 verb skills keep that surface small: plan, work, review, sync, release.

  1. You describe the outcome in normal language.
  2. /harness-plan drafts or updates spec.md and Plans.md with scope, acceptance criteria, unknowns, and stop conditions.
  3. Non-trivial planning records team_validation_mode and validates the plan through team/sub-agent or manual-pass perspectives for spec/Plans alignment, memory reuse, product fit, security fit, and works-in-practice.
  4. Harness treats those files as the source of truth. Data the agent has not seen stays unknown instead of being silently invented.
  5. /harness-work implements the approved slice with TDD and verification.
  6. /harness-review separates review from implementation.
  7. /harness-release packages only verified evidence.

Commands

Command What happens inside
/harness-setup Installs project guidance, command surfaces, hooks, and checks so the workflow starts from one known baseline.
/harness-plan Turns intent into spec.md and Plans.md, including scope, acceptance criteria, dependencies, unknowns, stop conditions, and non-trivial planning validation.
/harness-work Executes one approved task or range, adds tests when required, runs verification, and keeps work inside the plan.
/harness-work all Runs the approved plan through implementation and review paths; use after the plan is clear and the repo baseline is known.
/harness-review Reviews the result separately from implementation and treats major findings as blockers.
/harness-release Checks release readiness, CHANGELOG/tag boundaries, and evidence packaging after implementation and review are complete.
bin/harness doctor --migration-report Inventories old plugin caches, Codex skills, OpenCode files, symlinks, and memory state without deleting data.

Basic Workflow

Stage Output Gate
Investigate Evidence and unknowns Do not promote unobserved data into claims.
Plan spec.md + Plans.md User approves or corrects the generated contract.
Work Code and tests TDD required when the task says so.
Review Independent verdict Major findings block completion.
PR Evidence pack PR ready is not release ready.
Release Tag/release artifacts Release preflight must pass on the release path.

Non-engineer decision surfaces

Three single-screen HTML views surface the decision at each phase, so a non-engineer sponsor can judge without reading code:

  • Plan Brief (harness-plan-brief) — understanding, options, risks, and acceptance criteria before implementation. Offered when a plan is finalized.
  • Progress (harness-progress) — WIP/TODO/done counts and drift alerts during work. Auto-regenerated on a PostToolUse hook.
  • Acceptance (harness-accept) — per-criterion pass/fail with a ship/wait/reject recommendation before release.

Install By Tool

Tool Tier Route
Claude Code supported Claude plugin marketplace, then /harness-setup.
Codex CLI supported scripts/setup-codex.sh --user; live H4 workflow smoke (2026-07-17) + release-preflight fail-closed gate (H7, 2026-07-19); 3cli Bash PreToolUse floor — not Codex app parity.
Codex app candidate Candidate smoke only; do not reuse Codex CLI proof.
OpenCode internal-compatible scripts/setup-opencode.sh; runtime parity is not claimed.
Cursor supported scripts/setup-cursor.sh real-directory local install; workflow smoke + release-preflight fail-closed gate green; no FS jail — containment is harness-side, see docs/CURSOR_INTEGRATION.md.
Grok supported scripts/setup-grok.sh plugin package install/check; live H4 (2026-07-17) + H7 preflight; Claude-envelope PreToolUse floor — not full Claude hook parity.
Hermes Agent candidate Manual symlink research route only; dynamic slash discovery observed locally, runtime parity not claimed.
GitHub Copilot CLI candidate Manual profile research only.
Antigravity CLI future/unsupported No end-user install route in this phase.

Existing User Migration

Run bin/harness doctor --migration-report before changing an existing setup. The report inventories stale Claude plugin caches, duplicate Codex skills, old symlinks, OpenCode backup paths, and harness-mem state without deleting anything.

Support Boundary

Four install routes ≠ four identical capability guarantees. Setup scripts mean each tool has an entry path, not a shared product guarantee. Public 正式対応 maps to EN tier supported. Claude Code, Codex CLI, Cursor, and Grok passed H1–H8 on their verified claim paths (live H4 2026-07-17; H7 release-preflight fail-closed wiring 2026-07-19). Other rows in the install table stay at their listed tier (internal-compatible or candidate) until their own H1–H8 pass (docs/spec/planning-and-host-adapter.md; Phase 111).

EN tier JP public wording (safe)
supported 正式対応
internal-compatible 互換利用可 / 制限付き対応
candidate 試験対応 / プレビュー
future/unsupported 非対応 / 将来検討

Harness can describe candidate paths, but it does not inherit support claims from Superpowers, Hermes Agent, or any other project. A host only moves up when Harness has its own bootstrap, trigger, runtime, and release evidence.

not_observed != absent: missing local proof means "not proven here", not "impossible" and not "supported".

Requirements

  • Claude Code v2.1+ for the supported Claude path.
  • A project repository with write access for local setup.
  • No Node.js is required for the Go-native guardrail engine.
  • Optional harness-mem for cross-session memory when configured and healthy.

Advanced

Use these after the basic trigger path is visible.

Capability What it adds Boundary
Breezing Planner/Critic/Worker style team execution for larger task lists. Still gated by plan quality and review.
Codex companion review Schema-backed Codex second opinion through scripts/codex-companion.sh. Raw codex exec is not the Harness companion path.
OpenCode bootstrap Mirrors Harness guidance into OpenCode-compatible surfaces. Real runtime parity is not claimed.
harness-mem Project-scoped memory and recall across sessions. Optional companion; purge remains explicit.
auto-approve (experimental) HARNESS_AUTO_APPROVE=on currently records the enablement gate and prereq check result in the orchestration ledger only. Approval prompts are not skipped. Default OFF. Strict env value (on only). Gated on Phase 92.1.1 / 92.2.3 / 96.1.2 prereqs for ledger instrumentation; approval automation is deferred until HOTL governance verification (Phase 101 U0-U7 evidence).

Documentation

Resource Description
Tool-first onboarding Where to start by host tool.
Install routes Per-tool setup and support-tier boundaries.
Migration check Existing-user impact, compatibility, and rollback path.
Skill trigger gate How install success is verified.
Capability matrix Supported, internal-compatible, candidate, and unsupported host claims.
Claude Code Compatibility Current Claude Code requirements and compatibility notes.
Cursor Integration Cursor handoff boundary and supported adapter notes (harness-side containment).
Distribution Scope Included vs compatibility vs development-only paths.
Hardening parity Runtime safety differences between Claude hooks and Codex gates.
Work All Evidence Pack Success/failure verification contract for full-plan execution.
Language / i18n How to switch output language (English default, Japanese opt-in).
Changelog User-facing version history.

Contributing

Issues and PRs welcome. See CONTRIBUTING.md.

Acknowledgments

  • AI Masao - Hierarchical skill design
  • Beagle - Test tampering prevention patterns

License

MIT License. See LICENSE.md.

24 skills in this repo

Plugin marketplace
agent-browser

Browser automation through the repo agent-browser CLI. Explicit helper for navigation, forms, screenshots, scraping, and web-app checks. Prefer Browser Use or Playwright when available. Do NOT load for: sharing URLs, embedding links, or edi...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install agent-browser
breezing

Team execution mode (Codex host) — backward-compatible alias for harness-work with backend selection, including opt-in Cursor worker delegation. Composer/composer 2.5 maps to the cursor backend.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install breezing
breezing

Team execution mode — backward-compatible alias for harness-work with team orchestration. Composer/composer 2.5 maps to the cursor backend.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install breezing
cc-update-review

Quality guardrail for Claude/Codex update integration. Detects doc-only Feature Table additions and requires implementation or explicit planning. Internal use only.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install cc-update-review
ci

CI red? Call us. Pipeline fire brigade deploys. Use when user mentions CI failures, build errors, test failures, or pipeline issues. Do NOT load for: local builds, standard implementation work, reviews, or setup.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install ci
cursor-ask

Read-only delegate to cursor-agent (Composer) for questions, investigation, design discussion, and adversarial sanity checks. No worktree, no cherry-pick, no Lead diff review — cursor-agent is locked to ask mode and cannot write. Use when u...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install cursor-ask
cursor-do

Delegate a single write task to Cursor Composer via cursor-companion.sh inside an isolated worktree, then Lead-review the diff and cherry-pick. Use when user invokes cursor:do, says delegate to cursor, have composer write it, refactor with...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install cursor-do
cursor-review

Run a Cursor Composer review as an advisory second opinion while keeping the primary review verdict on the host brain. Use when user invokes cursor:review, asks Cursor to review, or wants composer to sanity-check a diff. Cursor never owns A...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install cursor-review
cursor-setup

Configure and verify the Cursor backend for Claude Code Harness. Use when user invokes cursor:setup, wants Cursor as the local default implementation backend, or asks to check Cursor plugin/agent readiness. Distribution default remains opt-...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install cursor-setup
failure-codifier

Extract recurring failure patterns from breezing orchestration logs and Judgment Ledger, emit failure-rule.v1 proposals with confidence scores. SSOT promotion to patterns.md or decisions.md is proposal-only — human-approval-required. Use wh...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install failure-codifier
harness-accept

Generate an Acceptance Demo HTML for non-engineer vibecoders right before ship/wait/reject decision. Reads back the acceptance_criteria that were stored as personal-preference.v1 by harness-plan-brief (joined by user_request_hash), then ren...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-accept
harness-loop

HAR: Codex-native long-running loop runner. Uses a real background runner that executes one ready batch per cycle through Breezing by default, with status/stop controls. Trigger: long-running, loop, autonomous, background, Codex. Do NOT loa...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-loop
harness-loop

Long-running task loop using /loop (Claude Code dynamic mode) and ScheduleWakeup to re-enter with fresh context on each wake-up. Internally invokes harness-work through Agent. Trigger: long-running, loop, wake-up, autonomous. Do NOT load fo...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-loop
harness-plan

HAR: Research-backed, team-validated task planning, Plans.md management, progress sync. Trigger: create a plan, add tasks, update Plans.md, mark complete, check progress. Do NOT load for: implementation, review, release.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-plan
harness-plan-brief

Generate a Plan Brief HTML for non-engineer vibecoders before implementation starts. Searches harness-mem (project-only) for relevant past decisions, patterns, and Plans archive entries, then renders a single-file HTML artifact summarizing...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-plan-brief
harness-progress

Generate a Progress Tracker HTML for non-engineer vibecoders to glance at session progress (cc:WIP / cc:TODO / cc:完了 counts, percentage, elapsed/estimated minutes, cost so far/estimate, drift alerts). Uses Plans.md as source of truth, ren...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-progress
harness-release

Generic release automation for projects using Keep a Changelog + GitHub. Single confirmation gate then end-to-end automation: bump detection, CHANGELOG promotion, PR/main merge, tag, GitHub Release. Trigger: release, version bump, publish....

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-release
harness-review

HAR: Multi-angle code, plan, scope review. Security/quality check. Trigger: review, code review, plan review, scope analysis. Do NOT load for: implementation, new features, bugfix, setup, release.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-review
harness-setup

HAR: Project init, tool setup, agent config, memory setup, skill mirror sync. Trigger: setup, init, new project, CI/Codex setup, harness-mem, mirror. Do NOT load for: implementation, review, release, planning.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-setup
harness-sync

HAR: Sync Plans.md with implementation. Drift detect, marker update, retrospective. Trigger: sync-status, where am I, check progress. --snapshot for snapshots. Do NOT load for: planning, implementation, review, release.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-sync
harness-work

HAR: Execute Plans.md tasks from single task to full parallel team run. Trigger: implement, execute, do everything, breezing, team run, parallel, composer, composer 2.5. Do NOT load for: planning, review, release, setup.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-work
harness-work

HAR: Execute Plans.md tasks from single task to full parallel team run. Trigger: implement, execute, do everything, breezing, team run, parallel, composer, composer 2.5. Do NOT load for: planning, review, release, setup.

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install harness-work
maintenance

File cleanup and archiving. Tidies up bloated Plans.md, session-log.md, old logs, and state files. Trigger: /maintenance, cleanup, archive, organize, split session-log. Do NOT load for: implementation, review, release, new feature developme...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install maintenance
memory

Manage SSOT, memory, and cross-tool memory search. Guardian of decisions.md and patterns.md. Use when user mentions memory, SSOT, decisions.md, patterns.md, merging, migration, SSOT promotion, sync memory, save learnings, memory search, har...

Install 
/plugin marketplace add Chachamaru127/claude-code-harness
/plugin install memory

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