learn-eval

learn-eval is a skill for Claude Code from shimo4228/claude-harness. It costs 42 tokens per session (3,552 once invoked), scanned A, original, MIT.

A workflow for extracting reusable lessons from the current coding session and deciding where they should be saved. It can place a lesson in an existing skill, rule, or document, or promote it to a new skill.

In plain words
What is it for?
Use it to review error fixes, debugging methods, workarounds, project patterns, and other lessons that may improve future work.
Why use it?
It prevents useful fixes and patterns from being recorded in unreachable notes or saved without checking whether they are reliable and reusable.

Skill for Claude Code

Written for Claude Code: user-invocable in frontmatter. Also seen: reads .claude/ paths; mentions Claude Code.

Good fit Use it to review error fixes, debugging methods, workarounds, project patterns, and other lessons that may improve future work.

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Install with agentmods
npx agentmods add skills/shimo4228/claude-harness/learn-eval
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 shimo4228/claude-harness --skill learn-eval
Clone the repo
git clone --depth 1 https://github.com/shimo4228/claude-harness

Made for: Claude Code.

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 learn-eval

README.md
[![agentmods](https://agentmods.dev/badge/skills/shimo4228/claude-harness/learn-eval/github.svg)](https://agentmods.dev/skills/shimo4228/claude-harness/learn-eval)
Your own site
<a href="https://agentmods.dev/skills/shimo4228/claude-harness/learn-eval"><img src="https://agentmods.dev/badge/skills/shimo4228/claude-harness/learn-eval/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 learn-eval

Your own site · 80×15
<a href="https://agentmods.dev/skills/shimo4228/claude-harness/learn-eval"><img src="https://agentmods.dev/badge/skills/shimo4228/claude-harness/learn-eval.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,552 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 $0.00042 $0.03552
Opus 5.5 $0.00017 $0.01421
Sonnet 5.5 $0.00008 $0.00710
Haiku 4.5 $0.00004 $0.00355

Measured 10d ago against content hash 6920b7f764be, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

learn-eval 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 10d ago.

The scan reads SKILL.md. This mod also ships 3 executable files (scripts/__init__.py, scripts/overlap_candidates.py, tests/test_overlap_candidates.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/learn-eval/SKILL.md · 261 lines

How it starts

The opening of the file, as written. The whole thing — 261 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/learn-eval - Extract, Evaluate, then Save

Extract a reusable pattern from the session, gate it, and route every Save to a destination something actually reaches.

What to Extract

Look for:

  1. Error Resolution Patterns — root cause + fix + reusability
  2. Debugging Techniques — non-obvious steps, tool combinations
  3. Workarounds — library quirks, API limitations, version-specific fixes
  4. Project-Specific Patterns — conventions, architecture decisions, integration patterns

Process

  1. Review the session for extractable patterns

  2. Identify the most valuable/reusable insight

  3. Determine the destination — there is no parking lot.

    Every Save must land somewhere that something actually routes to (ADR-0047), so pick one of exactly two:

    • Absorb into an existing asset — the pattern belongs inside a skill, rule, or hooks/README.md section that already owns the topic. Name the file and the section. This is the default: an addition to a reachable asset beats a new file. A skill's value lies in its comprehensiveness, so appending improves it — "I don't want to pollute the existing skill" routes the pattern to a file nothing reaches.
    • Promote to a skill — the pattern has its own independent trigger (a user request that no installed skill answers). Run skill: skill-creator (required by rules/common/skills.md before writing any skill).

    If neither fits, the verdict is Drop, not "park it somewhere for now". A note that nothing points at is reachable only by grep, and grep requires already knowing the content exists (measurement: ADR-0047).

    Global vs project placement (once a destination type is chosen): the source of truth is docs/adr/0025-global-vs-project-asset-placement.md.

  4. Draft the candidate as a scratch note (the final skill shape belongs to skill-creator; overlap_candidates.py reads name / description / Problem / Solution / When to Use):

Read the full file on GitHub · 261 lines

Files

What ships with it

5 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. 10d ago Changed · +3 lines 6920b7f764be
  2. 11d ago Changed · -94 tokens per session 8411fe883c0a
  3. 13d ago Changed · -1 lines 40c88fab2d86
  4. 24d ago Changed · -1 tokens per session 53a138b21501
  5. 25d ago Changed · -2 lines 23c0a48d47ca
  6. 1mo ago Changed · +7 lines c1de986d7ac5
  7. 1mo ago Changed · -10 lines c895e843d422
  8. 1mo ago First seen · 264 lines · 137 tokens per session scan A 931adb1360ce

Subscribe to this mod's changes

learn-eval is a skill published in the GitHub repository shimo4228/claude-harness (3 stars, last pushed 2d ago), licensed MIT. It adds 42 tokens to every session and 3,552 once invoked, about $0.0002 per session on Opus 5.5. 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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