harness-lessons SKILL.md skillA
harness-lessons from nerviz-ai/nerviz is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add nerviz-ai/nerviz/harness-lessons@git:20261028.19e69aePins git:20261028.19e69ae in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- nerviz-ai/nerviz
- Path
.claude/skills/harness-lessons/SKILL.md- Versions recorded
- 2
- Latest version
- git:20261028.19e69ae, committed Oct 28, 2026
- First version recorded
- Oct 28, 2026
- Size
- 9,025 bytes
- Repository stars
- 11
- License
- Apache-2.0
Measures what this `.claude/` costs in context — every session and per skill, agent, rule and hook — through `ArchHook.jar footprint`, reads the audit trail's spend, failures and peaks when the project records one, judges both against a curated baseline of Claude Code and Anthropic best practices, and writes `harness-NNN.md` — under `docs/lessons-learned/` in a generated project, `.claude/lessons-learned/` here: each finding with its evidence, the practice it breaks, the file that owns the fix…
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Harness Lessons
Turns the cost and behavior of this `.claude/` into a lesson its owner can act on. A skill
that loads 16k tokens, a rule with no `paths`, a hook that spawns on every tool call, an
agent that re-reads what its caller had: each one is paid in every session or every run, and
each one has exactly one owning file. This skill finds the owner, names the change and
estimates what it saves. It changes nothing in `.claude/` itself.
## Target
$ARGUMENTS
Empty: the whole harness. A skill or agent name: § 3 judges only that piece, § 1 and § 2 stay
whole — the numbers of one piece only mean something next to the others.
## Measured
!`java -jar "${CLAUDE_PROJECT_DIR:-.}/.claude/hooks/ArchHook.jar" footprint 2>&1`
## Spent
!`java -jar "${CLAUDE_PROJECT_DIR:-.}/.claude/hooks/ArchHook.jar" audit summary 2>&1`
---
**Never recompute a number the two blocks printed**, and never read every `SKILL.md` to
re-derive one: the arithmetic is Java on purpose (`references/best-practices.md` BP-12). Open a
file only to judge a finding the numbers already point at.
## Why this is a skill (Form 2)
…Read the whole file at its exact version.
How to install
mdr add nerviz-ai/nerviz/harness-lessons@sha256:2bd13f9856509810The line at the top of this page pins the label git:20261028.19e69ae, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_bu3fph7ywy74jino)
1 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, all committed on Oct 28, 2026.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261028.19e69ae latest | 2026-10-28 | 19e69ae | 9,025 B | A | view · diff |
| git:20261028.5c532c1 | 2026-10-28 | 5c532c1 | 8,969 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (9025 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
nerviz-ai/nerviz · 11 stars · license Apache-2.0 · pushed 2026-10-31 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_bu3fph7ywy74jino GET https://markdownregistry.com/api/v1/resolve?ref=nerviz-ai/nerviz/harness-lessons GET https://markdownregistry.com/api/v1/blob/2bd13f9856509810efd0787231e26830a8692a254326afd3205bcc56e63666c0
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
More from nerviz-ai/nerviz
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