eval-harness

A framework for checking whether Claude Code sessions complete tasks correctly. It uses evals, which are repeatable checks similar to unit tests, to measure new abilities and regressions.

In plain words
What is it for?
Defining expected outcomes, running code-based, model-based, or human checks, tracking regressions, and measuring success across repeated attempts.
Why use it?
It gives you a defined way to test agent behaviour before and after changes, instead of judging each result informally.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/codelably/harmony-claude-code/eval-harness
Any agent
npx skills add codelably/harmony-claude-code --skill eval-harness
Clone the repo
git clone --depth 1 https://github.com/codelably/harmony-claude-code

Made for: Claude Code, Codex.

Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,718 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00019 $0.01718
Opus 5 $0.00010 $0.00859
Sonnet 5 $0.00004 $0.00344
Haiku 4.5 $0.00002 $0.00172

Measured 2d ago against content hash 4333f5558ca9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

eval-harness 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 2d 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.

docs/zh-TW/skills/eval-harness/SKILL.md · 228 lines

How it starts

The opening of the file, as written. The whole thing — 228 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Eval Harness 技能

Claude Code 工作階段的正式評估框架,實作 eval 驅動開發(EDD)原則。

理念

Eval 驅動開發將 evals 視為「AI 開發的單元測試」:

  • 在實作前定義預期行為
  • 開發期間持續執行 evals
  • 每次變更追蹤回歸
  • 使用 pass@k 指標進行可靠性測量

Eval 類型

能力 Evals

測試 Claude 是否能做到以前做不到的事:

[CAPABILITY EVAL: feature-name]
任務:Claude 應完成什麼的描述
成功標準:
  - [ ] 標準 1
  - [ ] 標準 2
  - [ ] 標準 3
預期輸出:預期結果描述

回歸 Evals

確保變更不會破壞現有功能:

[REGRESSION EVAL: feature-name]
基準:SHA 或檢查點名稱
測試:
  - existing-test-1: PASS/FAIL
  - existing-test-2: PASS/FAIL
  - existing-test-3: PASS/FAIL
結果:X/Y 通過(先前為 Y/Y)

評分器類型

1. 基於程式碼的評分器

使用程式碼的確定性檢查:

# 檢查檔案是否包含預期模式
grep -q "export function handleAuth" src/auth.ts && echo "PASS" || echo "FAIL"

# 檢查測試是否通過
npm test -- --testPathPattern="auth" && echo "PASS" || echo "FAIL"

# 檢查建置是否成功
npm run build && echo "PASS" || echo "FAIL"

2. 基於模型的評分器

使用 Claude 評估開放式輸出:

[MODEL GRADER PROMPT]
評估以下程式碼變更:
1. 它是否解決了陳述的問題?
2. 結構是否良好?
3. 邊界案例是否被處理?
4. 錯誤處理是否適當?

分數:1-5(1=差,5=優秀)
理由:[解釋]

3. 人工評分器

標記為手動審查:

[HUMAN REVIEW REQUIRED]
變更:變更內容的描述
理由:為何需要人工審查
風險等級:LOW/MEDIUM/HIGH

指標

pass@k

「k 次嘗試中至少一次成功」

  • pass@1:第一次嘗試成功率
  • pass@3:3 次嘗試內成功
  • 典型目標:pass@3 > 90%

pass^k

「所有 k 次試驗都成功」

  • 更高的可靠性標準
  • pass^3:連續 3 次成功
  • 用於關鍵路徑

Eval 工作流程

1. 定義(編碼前)

## EVAL 定義:feature-xyz

### 能力 Evals
1. 可以建立新使用者帳戶
2. 可以驗證電子郵件格式
3. 可以安全地雜湊密碼

### 回歸 Evals
1. 現有登入仍可運作
2. 工作階段管理未變更
3. 登出流程完整

### 成功指標
- 能力 evals 的 pass@3 > 90%
- 回歸 evals 的 pass^3 = 100%

2. 實作

撰寫程式碼以通過定義的 evals。

3. 評估

# 執行能力 evals
[執行每個能力 eval,記錄 PASS/FAIL]

# 執行回歸 evals
npm test -- --testPathPattern="existing"

# 產生報告

4. 報告

EVAL 報告:feature-xyz
========================

能力 Evals:
  create-user:     PASS (pass@1)
  validate-email:  PASS (pass@2)
  hash-password:   PASS (pass@1)
  整體:           3/3 通過

回歸 Evals:
  login-flow:      PASS
  session-mgmt:    PASS
  logout-flow:     PASS
  整體:           3/3 通過

指標:
  pass@1: 67% (2/3)
  pass@3: 100% (3/3)

狀態:準備審查

Read the full file on GitHub · 228 lines

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. 2d ago First seen · 228 lines · 19 tokens per session scan A 4333f5558ca9

Subscribe to this mod's changes

eval-harness is a skill published in the GitHub repository codelably/harmony-claude-code (42 stars, last pushed 6mo ago), licensed MIT. It adds 19 tokens to every session and 1,718 once invoked, about $0.0001 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 2026-08-30.

Related

Other skills, from other repositories

systematic-debugging

Use when encountering any bug, test failure, or unexpected behavior, before proposing fixes.

obra/superpowers · 21 tokens

brainstorming

You MUST use this before any creative work - creating features, building components, adding functionality, or modifying behavior. Explores user intent, requirements and design before implementation.

obra/superpowers · 37 tokens

chat-pet-sprite-creation

Use when creating or changing VS Code chat pet sprite art, sprite sheets, state animations, eye treatments, Stable/Insiders variants, or pet transitions under src/vs/workbench/contrib/chat/browser/widget/media/chatPet.

microsoft/vscode · 53 tokens

cpu-profile-analysis

Analyze V8/Chrome CPU profiles (.cpuprofile) and DevTools trace files (Trace-.json). Use when: profiling performance, investigating slow functions, comparing code paths, finding bottlenecks, analyzing timeToRequest, understanding call trees from sampling profiler data, analyzing layout/paint/rendering, investigating…

microsoft/vscode · 71 tokens

agent-host-chat-contributions

Build and review cross-cutting agent-host chat behavior through lifecycle contributions. Use when adding turn lifecycle side effects, prompt or context injection, restored-history transformation, protocol-action observation, or when reviewing changes that add code to AgentSideEffects or AgentService.

microsoft/vscode · 56 tokens

auto-perf-optimize

Run agent-driven VS Code performance or memory investigations. Use when asked to launch Code OSS, automate a VS Code scenario, run the Chat memory smoke runner, capture renderer heap snapshots, take workflow screenshots, compare run summaries, or drive a repeatable scenario before heap-snapshot analysis.

microsoft/vscode · 62 tokens