harness-retro

harness-retro is a skill for Claude Code, Codex from nnabuuu/harness-engineering-toolkit. It costs 130 tokens per session (3,424 once invoked), scanned A, original, MIT.

A review tool for completed harness tasks, using run data, evaluation reports, and change logs to find recurring problems and suggest improvements.

In plain words
What is it for?
Use it to review one or more completed harness tasks, compare their results, improve prompts, scoring rules, and completion conditions, and optionally archive finished tasks.
Why use it?
It helps reveal why tasks stall, repeat work, or spend resources inefficiently. It also keeps findings and suggested prompt or scoring changes in a written report.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to review one or more completed harness tasks, compare their results, improve prompts, scoring rules, and completion conditions, and optionally archive finished tasks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nnabuuu/harness-engineering-toolkit/harness-retro
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add nnabuuu/harness-engineering-toolkit --skill harness-retro
Clone the repo
git clone --depth 1 https://github.com/nnabuuu/harness-engineering-toolkit

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for harness-retro

README.md
[![agentmods](https://agentmods.dev/badge/skills/nnabuuu/harness-engineering-toolkit/harness-retro/github.svg)](https://agentmods.dev/skills/nnabuuu/harness-engineering-toolkit/harness-retro)
Your own site
<a href="https://agentmods.dev/skills/nnabuuu/harness-engineering-toolkit/harness-retro"><img src="https://agentmods.dev/badge/skills/nnabuuu/harness-engineering-toolkit/harness-retro/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for harness-retro

Your own site · 80×15
<a href="https://agentmods.dev/skills/nnabuuu/harness-engineering-toolkit/harness-retro"><img src="https://agentmods.dev/badge/skills/nnabuuu/harness-engineering-toolkit/harness-retro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 130 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,424 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00130 $0.03424
Opus 5 $0.00065 $0.01712
Sonnet 5 $0.00026 $0.00685
Haiku 4.5 $0.00013 $0.00342

Measured 8d ago against content hash 5c130d3ccddc, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

harness-retro scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

harness-retro/SKILL.md · 324 lines

How it starts

The opening of the file, as written. The whole thing — 324 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Harness Retrospective

Analyze completed harness runs to extract patterns and generate concrete improvements to prompts, rubrics, and exit conditions. This is L4 — the evaluation loop applied to the harness system itself.

Self-Review Checklist (read BEFORE and AFTER every phase)

Discovery Guards

  • Scanned ALL task directories in .harness-workspace/, not just first match
  • Verified each task has enough data to analyze (at minimum: state.json or progress.md)
  • Confirmed scope with user before starting analysis

Analysis Guards

  • Read ALL eval reports and changelogs for selected tasks
  • Did not skip any dimension — marked "insufficient data" if data missing
  • All findings cite specific evidence (iteration numbers, scores, file paths)
  • Cross-task analysis (D6) only when 2+ tasks selected

Report Guards

  • Improvement suggestions include concrete diffs, not just descriptions
  • Suggestions reference specific dimension names from EVAL_CRITERIA.md
  • Report saved to RETRO.md in the task directory (single-task) or .harness-workspace/RETRO-{date}.md (multi-task)

Archive Guards

  • Archive only after retro report is complete (Entry A) OR after user acknowledges no RETRO.md (Entry B)
  • User explicitly confirmed before any file operations
  • Entire task directory moved to _archive/, not left split across two locations
  • DAGU symlink updated to point to new _archive/ path (execution history preserved)

Entry Point Detection

Determine which entry point the user needs before starting any phase.

  • Entry A — Full Retro: Phases 1 → 2 → 3 → 4 (archive optional at end). The complete retrospective flow.
  • Entry B — Standalone Archive: Skip directly to Phase 4A. Archive completed/failed tasks without running analysis.

Detection Rules

User says Entry
"archive harness", "archive task", "clean up workspace", "归档harness", "归档" Entry B
"retro", "retrospective", "review harness", "analyze harness", "复盘", "回顾", "总结harness" Entry A
Unclear or ambiguous Ask: "Do you want a full retrospective (analysis + improvements), or just archive completed tasks?"

Read the full file on GitHub · 324 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 324 lines · 130 tokens per session scan A 5c130d3ccddc

Subscribe to this mod's changes

harness-retro is a skill published in the GitHub repository nnabuuu/harness-engineering-toolkit (5 stars, last pushed 1mo ago), licensed MIT. It adds 130 tokens to every session and 3,424 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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