How do I install the Harness Implement skill?

Run npx skillmds@latest add vasuag09/harness-implement in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Harness Implement safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Harness Implement?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Harness Implement free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Harness Implement?

vasuag09 (@vasuag09) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Harness Implement by vasuag09 — Agent Skill

Name: Harness Implement
Author: vasuag09

Harness Implement

Orchestrate the entire IMPLEMENT phase — test-driven implementation of the approved plan, resolving build/type errors as they arise. Use after /harness-plan. Sequences /implement and /build-fix, delegates to subagents, and halts if reality diverges from the plan.

vasuag09 Updated Sep 21, 2026

File contents

/harness-implement — run the Implement phase

Thin orchestrator over the Implement skills. Requires an approved plan from /harness-claude:harness-plan (or /harness-claude:plan). Refuse to start without one for non-trivial work.

Sequence

For each plan phase, in order:
- /harness-claude:implement — delegate to the harness-claude:tdd-guide agent: failing test (RED) → minimum code (GREEN) → refactor, against the phase's acceptance criteria.
- Parallel-fan-out checkpoint (mandatory when it triggers): before editing a phase serially, if it spans 3+ independent files with disjoint write-sets and no dependency, you must surface /harness-claude:orchestrate — name the file split and let the user choose. The offer is not optional (that's the only way parallel mode fires); acting on it stays opt-in — never auto-start a multi-agent run.
- Let the format/typecheck/quality hooks run; act on what they surface.
- If the build/types break and the fix isn't obvious → /harness-claude:build-fix (delegate to the harness-claude:build-error-resolver agent), minimal diffs only.
- Confirm the phase's exit check (tests green, build clean) before the next phase.
Plan-divergence gate: if reality contradicts the plan (a phase is wrong, missing, or bigger than scoped), HALT — report the divergence, update the plan with the user, then resume. Never silently improvise scope.

Rules

Delegate search/exploration and isolated edits to cheaper models; keep the orchestrator focused on integration.
Files stay modular and lean (<800 lines), immutable patterns, validated inputs.
Compact at phase boundaries, not mid-phase.
Do not commit or push — branch creation follows rules/git.md (branch-at-first-write in /harness-claude:implement).

Output

Phase-by-phase summary (what was built, tests added, build status). Then hand off to /harness-claude:harness-verify.

---name: harness-implementdescription: Orchestrate the entire IMPLEMENT phase — test-driven implementation of the approved plan, resolving build/type errors as they arise. Use after /harness-plan. Sequences /implement and /build-fix, delegates to subagents, and halts if reality diverges from the plan.---# /harness-implement — run the Implement phaseThin orchestrator over the Implement skills. Requires an approved plan from`/harness-claude:harness-plan` (or `/harness-claude:plan`). Refuse to start without one for non-trivial work.## Sequence1. For each plan phase, in order: - **`/harness-claude:implement`** — **delegate to the `harness-claude:tdd-guide` agent**: failing test (RED) → minimum code (GREEN) → refactor, against the phase's acceptance criteria. - **Parallel-fan-out checkpoint (mandatory when it triggers):** before editing a phase serially, if it spans 3+ independent files with disjoint write-sets and no dependency, you **must** surface `/harness-claude:orchestrate` — name the file split and let the user choose. The offer is not optional (that's the only way parallel mode fires); *acting* on it stays opt-in — never auto-start a multi-agent run. - Let the format/typecheck/quality hooks run; act on what they surface. - If the build/types break and the fix isn't obvious → **`/harness-claude:build-fix`** (delegate to the `harness-claude:build-error-resolver` agent), minimal diffs only. - Confirm the phase's **exit check** (tests green, build clean) before the next phase.2. **Plan-divergence gate:** if reality contradicts the plan (a phase is wrong, missing, or bigger than scoped), **HALT** — report the divergence, update the plan with the user, then resume. Never silently improvise scope.## Rules- Delegate search/exploration and isolated edits to cheaper models; keep the orchestrator focused on integration.- Files stay modular and lean (<800 lines), immutable patterns, validated inputs.- Compact at phase boundaries, not mid-phase.- Do **not** commit or push — branch creation follows `rules/git.md` (branch-at-first-write in `/harness-claude:implement`).## OutputPhase-by-phase summary (what was built, tests added, build status). Then hand off to`/harness-claude:harness-verify`.

Frequently asked questions