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-catch-up)<a href="https://agentmods.dev/skills/appsvortex/arness/arn-code-catch-up"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-code-catch-up/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-catch-up"><img src="https://agentmods.dev/badge/skills/appsvortex/arness/arn-code-catch-up.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 | $0.00087 | $0.02656 |
| Opus 5.5 | $0.00035 | $0.01062 |
| Sonnet 5.5 | $0.00017 | $0.00531 |
| Haiku 4.5 | $0.00009 | $0.00266 |
Grade A, and why
arn-code-catch-up 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 — 248 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Arness Catch-Up
Developers sometimes bypass the pipeline for quick fixes -- the "2am gap." These commits ship without specs, plans, or records, leaving holes in the artifact trail. Catch-up scans git history, identifies commits that have no corresponding Arness artifacts, and generates lightweight CATCHUP_ records in the CHANGE_RECORD.json envelope. The records are honest about what can and cannot be recovered retroactively: they document what changed (files, diffs, commit messages) and explicitly flag what is unknown (intent, test coverage, architectural reasoning).
This is a standalone skill. It operates outside the main pipeline and can be run at any time.
Step 0: Ensure Configuration
Read ${CLAUDE_PLUGIN_ROOT}/skills/arn-code-ensure-config/references/step-0-fast-path.md and follow its instructions. This guarantees a user profile exists and ## Arness is configured with Arness Code fields before proceeding.
Step 1: Load Configuration
Read the ## Arness section from CLAUDE.md. Extract the following fields:
- Plans directory -- where Arness project artifacts live (CHANGE_RECORD.json files, SWIFT_, STANDARD_, CATCHUP_* directories)
- Specs directory -- where spec files live (for boundary detection)
- Code patterns -- path to pattern documentation (for pattern refresh in Step 6)
- Template path -- path to report templates (for CATCHUP_REPORT_TEMPLATE.json)
- Template version -- plugin version the templates were copied from (if present)
- Template updates -- user preference:
ask,auto, ormanual(if present)
Template version check: If Template version and Template updates fields are present, run the template version check procedure documented in ${CLAUDE_PLUGIN_ROOT}/skills/arn-code-save-plan/references/template-versioning.md before proceeding. If ## Arness does not contain these fields, treat as legacy and skip.
Validate that all paths exist. If the plans directory does not exist, inform the user: "Plans directory not found. Run /arn-planning to set up Arness." and exit.
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 · 248 lines · 87 tokens per session scan A bef605478890
arn-code-catch-up is a skill published in the GitHub repository AppsVortex/arness (33 stars, last pushed 2mo ago), licensed MIT. It adds 87 tokens to every session and 2,656 once invoked, about $0.0003 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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