anchors

anchors is a skill for Claude Code from a2ngerer/claude_onboarding_agent. It costs 45 tokens per session (2,338 once invoked), scanned A, original, MIT.

A skill that refreshes marked sections in CLAUDE.md and AGENTS.md by fetching updated anchor content and comparing it with the files.

In plain words
What is it for?
Previewing or applying updates to anchor-based instructions, with a dry-run option for reviewing differences first.
Why use it?
It keeps generated instruction sections current while limiting changes to the sections this skill owns.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: reads .claude/ paths; mentions CLAUDE.md; mentions subagents.

Part of the claude-onboarding-agent plugin — 16 skills, 4 agents, 1 hook shipped together

Good fit Previewing or applying updates to anchor-based instructions, with a dry-run option for reviewing differences first.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/a2ngerer/claude_onboarding_agent/anchors
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 a2ngerer/claude_onboarding_agent --skill anchors
Clone the repo
git clone --depth 1 https://github.com/a2ngerer/claude_onboarding_agent

Made for: Claude Code.

Or install claude-onboarding-agent, the plugin that ships this one along with the rest of its 16 skills, 4 agents, 1 hook.

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 anchors

README.md
[![agentmods](https://agentmods.dev/badge/skills/a2ngerer/claude_onboarding_agent/anchors/github.svg)](https://agentmods.dev/skills/a2ngerer/claude_onboarding_agent/anchors)
Your own site
<a href="https://agentmods.dev/skills/a2ngerer/claude_onboarding_agent/anchors"><img src="https://agentmods.dev/badge/skills/a2ngerer/claude_onboarding_agent/anchors/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 anchors

Your own site · 80×15
<a href="https://agentmods.dev/skills/a2ngerer/claude_onboarding_agent/anchors"><img src="https://agentmods.dev/badge/skills/a2ngerer/claude_onboarding_agent/anchors.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 45 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,338 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00045 $0.02338
Opus 5 $0.00023 $0.01169
Sonnet 5 $0.00009 $0.00468
Haiku 4.5 $0.00005 $0.00234

Measured 10d ago against content hash 682af3c8733c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

anchors 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.

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/anchors/SKILL.md · 246 lines

How it starts

The opening of the file, as written. The whole thing — 246 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Anchors — Refresh Anchor-Derived Sections

Refresh the marker sections of CLAUDE.md / AGENTS.md that were originally rendered by a setup skill from anchor content.

Ownership

This skill is the sole writer of anchor-derived marker sections (section=anchor-<slug> inside CLAUDE.md / AGENTS.md). Other skills — including /upgrade-setup — detect anchor markers but never rewrite them; they delegate any refresh to this skill. The boundary is: /upgrade-setup refreshes plugin-template-derived sections only, and /anchors refreshes anchor-derived sections only. Running /upgrade-setup never mutates anchor bodies, so a user who wants both kinds of refresh runs /upgrade-setup followed by /anchors (or just /anchors if only anchor content needs updating).

Language

Detect language from the user's first message in this invocation and respond in it throughout. All file content written to disk stays in English (repo language rule).

Argument parsing

The invocation may contain --dry-run anywhere in the argument string.

  • If present: set dry_run: true. Print diffs but write nothing.
  • Otherwise: set dry_run: false.

Any other argument is ignored silently.

Pass 1 — Detect the setup

Step 1.1 — Read meta file

Read ./.claude/onboarding-meta.json if it exists. Expected shape per skills/_shared/write-meta.md.

  • If the file parses and setup_type is a recognized slug (one of: coding, data-science, design, knowledge-base, devops, content-voice, office, research, academic-writing, web-development) → set detected_setup: <setup_type>, meta_source: meta-file.
  • If the file parses and setup_type is graphify → print "/anchors has no work to do for a standalone graphify setup — anchor sections only apply to primary setups." and exit cleanly.
  • If the file is missing or malformed → ask the user: "No setup detected. Which setup type does this project use? (coding, data-science, design, devops, web-development, knowledge-base, content-voice, office, research, academic-writing)". Accept any of those ten as detected_setup. Any other reply → exit without changes.

Read the full file on GitHub · 246 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. 10d ago First seen · 246 lines · 45 tokens per session scan A 682af3c8733c

Subscribe to this mod's changes

anchors is a skill published in the GitHub repository a2ngerer/claude_onboarding_agent (5 stars, last pushed yesterday), licensed MIT. It adds 45 tokens to every session and 2,338 once invoked, about $0.0002 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 2026-08-31.

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