Getting it into your agent
This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.
/plugin marketplace add AppsVortex/arness/plugin install arn-codeWrote 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.
[](https://agentmods.dev/skills/appsvortex/arness/arn-code-simplify)<a href="https://agentmods.dev/skills/appsvortex/arness/arn-code-simplify"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-code-simplify/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.
<a href="https://agentmods.dev/skills/appsvortex/arness/arn-code-simplify"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-code-simplify.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00126 | $0.03479 |
| Opus 5.5 | $0.00050 | $0.01392 |
| Sonnet 5.5 | $0.00025 | $0.00696 |
| Haiku 4.5 | $0.00013 | $0.00348 |
Grade A, and why
arn-code-simplify 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 1mo 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.
How it starts
The opening of the file, as written. The whole thing — 277 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arness Simplify
Analyze recently implemented code for reuse opportunities, quality issues, and efficiency problems. Dispatches three parallel reviewers (code reuse, code quality, efficiency), merges findings, applies user-approved fixes with test verification, and generates a structured simplification report.
This is a post-execution quality improvement skill. It runs after implementation is complete (after execute-plan, swift, or bug-spec) and before review-implementation.
This is an execution skill. It runs in normal conversation (NOT plan mode).
Prerequisites
If no ## Arness section exists in the project's CLAUDE.md, inform the user: "Arness is not configured for this project yet. Run /arn-implementing to get started — it will set everything up automatically." Do not proceed without it.
Pipeline Position
execute --> **arn-code-simplify** --> review-implementation --> document-project --> ship
Arness-simplify is an optional step between execution and review. It can be triggered:
- By arn-implementing as Gate G3 (opt-in)
- By the user directly after any execution completes
- As a next-step offer from arn-code-execute-plan, arn-code-execute-task, or arn-code-swift
Workflow
Step 1: Load Configuration
-
Read the project's CLAUDE.md and extract the
## Arnesssection to find:- Plans directory
- Code patterns path
- Template path
- Template version and Template updates preference (if present)
-
If the
## Arnesssection is missing, inform the user: "Arness is not configured for this project yet. Run/arn-implementingto get started — it will set everything up automatically." Do not proceed. -
Load pattern documentation from the code patterns directory:
code-patterns.md(required)testing-patterns.md(required)architecture.md(required)ui-patterns.md(if it exists)security-patterns.md(if it exists)
-
If pattern documentation is missing, invoke the
arn-code-codebase-analyzeragent to generate fresh analysis. If the analyzer is unavailable, suggest running/arn-implementingto get started.
What ships with it
2 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.
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.
- 1mo ago First seen · 277 lines · 126 tokens per session scan A 208c14260443
arn-code-simplify is a skill published in the GitHub repository AppsVortex/arness (33 stars, last pushed 2mo ago), licensed MIT. It adds 126 tokens to every session and 3,479 once invoked, about $0.0005 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 2026-08-30.
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audit
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