skill-builder

A tool for creating and maintaining packages that define coding-agent skills. It builds the package’s metadata and supporting files, then checks or repairs their structure.

In plain words
What is it for?
Use it to create a new skill package, bring in an external skill’s structure, check a package, repair its hygiene, or audit its layout.
Why use it?
It removes the need to assemble skill files by hand and helps keep one clear source of truth. It also finds structural problems and owned files that are out of sync.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/boshu2/agentops/skill-builder
Any agent
npx skills add boshu2/agentops --skill skill-builder
Clone the repo
git clone --depth 1 https://github.com/boshu2/agentops

Made for: Claude Code, Codex.

Per session 71 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,646 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00071 $0.01646
Opus 5 $0.00036 $0.00823
Sonnet 5 $0.00014 $0.00329
Haiku 4.5 $0.00007 $0.00165

Measured 2d ago against content hash d191ad1ea7e4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

skill-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 2d 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.

images/gemini/skills/skill-builder/SKILL.md · 184 lines

How it starts

The opening of the file, as written. The whole thing — 184 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Builder — Create, heal, and audit skill packages

skill-builder owns the full structural lifecycle of one skills/<slug>/ source package: create it, verify its structure, repair owned projections, and audit its content discipline. It does not schedule work, allocate writers, operate Git, validate a software candidate, promote learnings, or decide what happens after a failure.

Before creating a new root, search skills/*/SKILL.md for an existing owner. Extend an existing skill when it already owns the requested behavior.

Modes

Trigger phrases Mode Entry point
"create a skill", "scaffold skill", "new skill" create (build) scripts/build.sh
"absorb external skill" create (absorb-external) scripts/build.sh
"check skill package" check scripts/heal.sh --check [--strict]
"heal skill", "repair skill hygiene" heal scripts/heal.sh --fix
"audit skill structure" audit scripts/audit.sh

Constraints

  • Create exactly one source package because metadata must have one canonical owner.
  • Treat external skills as structural signals only because clean-room output must not copy names, prose, prompts, scripts, or examples.
  • Regenerate projections once and stop because validation, revision, Git, and delivery remain caller-owned.
  • Check and audit modes never mutate files; fix mode changes only an explicit source target and its owned projections, because source behavior remains human-authored.

Create mode

Choose exactly one build input:

  • from-scratch <slug> creates a blank source package.
  • from-template <slug> --like <existing-slug> uses the existing skill only for metadata defaults; it does not copy its prose.
  • absorb-external <slug> --from <path> verifies the source exists, then creates a clean-room blank package without copying names, prose, prompts, scripts, or examples.

The caller may set SKILL_TIER, SKILL_DEPENDENCIES, SKILL_CAPABILITIES, and SKILL_EFFECTS. Values that represent lists must be JSON arrays.

Read the full file on GitHub · 184 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. 2d ago First seen · 184 lines · 71 tokens per session scan A d191ad1ea7e4

Subscribe to this mod's changes

skill-builder is a skill published in the GitHub repository boshu2/agentops (431 stars, last pushed 4d ago), licensed Apache-2.0. It adds 71 tokens to every session and 1,646 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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