skill-os-builder

skill-os-builder is a skill for Claude Code from naveedharri/benai-skills. It costs 75 tokens per session (1,358 once invoked), scanned A, original, MIT.

A builder for a personal second-brain system packaged as one portable AI skill. It stores personal context in files and uses a short router file to direct the AI to the right information.

In plain words
What is it for?
Use it to create a skill-based system for tracking selected areas such as projects, notes, people, or routines, based on a short interview about your needs.
Why use it?
It provides a simple way to organize personal knowledge without a separate vault, cloud service, or connection to another server. It is intended for one person and does not provide live team syncing.

Skill for Claude Code

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

Part of the aios plugin — 3 skills shipped together

Good fit Use it to create a skill-based system for tracking selected areas such as projects, notes, people, or routines, based on a short interview about your needs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/naveedharri/benai-skills/skill-os-builder
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 naveedharri/benai-skills --skill skill-os-builder
Clone the repo
git clone --depth 1 https://github.com/naveedharri/benai-skills

Made for: Claude Code.

Or install aios, the plugin that ships this one along with the rest of its 3 skills.

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 skill-os-builder

README.md
[![agentmods](https://agentmods.dev/badge/skills/naveedharri/benai-skills/skill-os-builder/github.svg)](https://agentmods.dev/skills/naveedharri/benai-skills/skill-os-builder)
Your own site
<a href="https://agentmods.dev/skills/naveedharri/benai-skills/skill-os-builder"><img src="https://agentmods.dev/badge/skills/naveedharri/benai-skills/skill-os-builder/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 skill-os-builder

Your own site · 80×15
<a href="https://agentmods.dev/skills/naveedharri/benai-skills/skill-os-builder"><img src="https://agentmods.dev/badge/skills/naveedharri/benai-skills/skill-os-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 75 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,358 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 warn 7 Sept 2026
SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • medium Rogue Agent · line 8
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
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 $0.00075 $0.01358
Opus 5 $0.00037 $0.00679
Sonnet 5 $0.00015 $0.00272
Haiku 4.5 $0.00007 $0.00136

Measured 11d ago against content hash d0579e6e88f8, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

skill-os-builder 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 11d 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.

plugins/aios/skills/skill-os-builder/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill OS Builder

You help the user create a Skill OS: their entire second brain packaged as one Claude skill. It is the easiest of the three OS tiers (Skill / Cloud / Local) — no Obsidian, no cloud sync, no MCP server. The skill's SKILL.md is the router; the context/ files are the brain.

Read references/structure-spec.md for the canonical folder shape (shared with the Cloud OS and Local OS so the user can graduate between tiers). Read references/routing-patterns.md before writing the generated router.

Tradeoffs — say these upfront

  • ✅ Easiest, zero infra, fully portable (it's just a folder).
  • ✅ Claude reads it natively; no setup beyond dropping it in ~/.claude/skills/.
  • ❌ Single-user, no live multiplayer, no realtime sync across devices.
  • ❌ Grows in one folder — great for personal use, not a team vault.

Build flow

  1. Explain the tradeoffs above; confirm Skill OS is the right tier.
  2. Interview (keep it short):
    • Name / what to call the OS
    • Their role + voice/preferences (for about-me.md)
    • What they want to track — pick from: projects, notes/intelligence, people, systems/routines. Only include what they need.
  3. Scaffold the OS folder from templates/:
    • SKILL.mdtemplates/_SKILL.md.tmpl (short router: CLAUDE.md-style rules
      • routing table — NO long content)
    • context/*.md ← the templates they chose
    • Frontmatter must be valid YAML. Keep description on ONE line wrapped in double quotes (description: "…"). Never leave it as an unquoted multi-line scalar — colons (Trigger phrases:) and inner quotes break the YAML and the skill is rejected on upload. Don't put " inside the quoted description; use plain words for trigger phrases.
  4. Confirm the layout — DON'T skip this. Show the user the full tree you just created (the folder, SKILL.md, and every context/ file) and ask: "Does this layout look right, or do you want to add / rename / remove anything — another context file, a sub-folder, etc.?" Apply whatever they ask, and keep the SKILL.md routing table in sync with the final file list before moving on.
  5. Populate the content — DON'T ship empty or placeholder files. Ask the user in ONE go to dump everything they have at once"Upload any files or just paste all your context here — projects, notes, people, routines, whatever you've got. Don't worry about organizing it; I'll sort it into the right files." Then YOU split that material across the context files by topic (projects → projects.md, people → people.md, etc.). Don't make them go file by file. After sorting, show what landed where and ask if anything's miscategorized or missing. If a file ends up with nothing, leave a one-line note of what it's for rather than fake filler.
  6. Package as a zip (so they can upload it anywhere — Cowork, Claude Desktop, the API). Zip the contents of the OS folder so SKILL.md sits at the root of the zip — never wrap it in an extra folder. Run from inside the generated folder:
    cd <name> && zip -rX "../<name>.zip" . -x '.*' '*/.*'
    
    Then verify before handing it over:
    • unzip -l <name>.zip — the listing MUST show SKILL.md at the top level (e.g. SKILL.md, context/...), NOT <name>/SKILL.md.
    • Frontmatter parses as YAML: unzip -p <name>.zip SKILL.md | sed -n '/^---$/,/^---$/p' | python3 -c 'import sys,yaml; yaml.safe_load(sys.stdin.read().strip().strip("-"))' — it must exit cleanly with no error. Hand them the path to <name>.zip.
  7. Place + test: tell them to put it in ~/.claude/skills/<name>/, restart, and ask Claude something that should route to a context file. (Or just upload the zip into Cowork and start using it there.)
  8. Graduating later: the same context/ shape moves straight into a Cloud OS or Local OS — point them to cloud-os-builder when they need sync.

Read the full file on GitHub · 86 lines

Files

What ships with it

8 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. 11d ago First seen · 86 lines · 75 tokens per session scan A d0579e6e88f8

Subscribe to this mod's changes

skill-os-builder is a skill published in the GitHub repository naveedharri/benai-skills (61 stars, last pushed 7d ago), licensed MIT. It adds 75 tokens to every session and 1,358 once invoked, about $0.0004 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 2026-08-30.

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