building-skills

building-skills is a skill for Claude Code, Codex from bh-rat/steer. It costs 106 tokens per session (1,708 once invoked), scanned A, original, MIT.

A guided workflow for creating an Agent Skill, a reusable set of instructions for a coding agent. It covers planning, scaffolding, writing, validation, and a real test run.

In plain words
What is it for?
Use it to create, review, improve, or validate skills for APIs, documents, and recurring development tasks.
Why use it?
It helps turn a repeated workflow or reference document into a checked, usable skill instead of an untested draft.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to create, review, improve, or validate skills for APIs, documents, and recurring development tasks.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/bh-rat/steer/building-skills
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 bh-rat/steer --skill building-skills
Clone the repo
git clone --depth 1 https://github.com/bh-rat/steer

Made for: Claude Code, Codex.

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 building-skills

README.md
[![agentmods](https://agentmods.dev/badge/skills/bh-rat/steer/building-skills/github.svg)](https://agentmods.dev/skills/bh-rat/steer/building-skills)
Your own site
<a href="https://agentmods.dev/skills/bh-rat/steer/building-skills"><img src="https://agentmods.dev/badge/skills/bh-rat/steer/building-skills/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 building-skills

Your own site · 80×15
<a href="https://agentmods.dev/skills/bh-rat/steer/building-skills"><img src="https://agentmods.dev/badge/skills/bh-rat/steer/building-skills.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 106 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,708 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.
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 $0.00106 $0.01708
Opus 5 $0.00053 $0.00854
Sonnet 5 $0.00021 $0.00342
Haiku 4.5 $0.00011 $0.00171

Measured 8d ago against content hash 95c782f7064f, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

building-skills 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 8d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/steer.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/building-skills/SKILL.md · 143 lines

How it starts

The opening of the file, as written. The whole thing — 143 lines — stays where its author put it; the contents beside it link to each section on GitHub.

building-skills

Build an Agent Skill the deliberate way: design the trigger and the components with the user, scaffold with steer new, write the body, and prove the result with steer validate and a real run. The user gets an installed, spec-valid skill, not a plausible-looking draft.

This skill bundles its own steer runtime at scripts/steer.py for its flow and learning; authoring the new skill additionally needs the installed steer CLI, checked below.

Before you start

  1. Check steer. Run steer --version. If it is missing, ask the user to install it (uv tool install steer-ai or pip install steer-ai), then continue; do not hand-roll a lookalike scaffold as a fallback.
  2. Set two paths. SKILL is this skill's own directory (this file's parent); WS is the new skill's directory, decided during design; it does not need to exist yet.
  3. Apply past lessons. Run python3 "$SKILL/scripts/steer.py" learn show and follow what it says; those lessons came from real previous builds.
  4. Improving rather than building? For a review or tune-up of an existing skill, skip the flow and follow references/improving-a-skill.md.

Process

This build runs behind an enforced flow: steps verify themselves against reality, and you cannot skip ahead. The flow lives next to this file and operates on the new skill's directory:

python3 "$SKILL/scripts/steer.py" flow status --workspace "$WS"
python3 "$SKILL/scripts/steer.py" flow next --workspace "$WS"
python3 "$SKILL/scripts/steer.py" flow done <step-id> --workspace "$WS"

The steps, and what completes them:

  1. design (mandate): triage the source material, make the four decisions below, and compose the exact steer new command. Show the user the command, the name, and the install scope; mark the step done when they agree.
  2. scaffold (verified): run the agreed command. Completes when SKILL.md exists in the workspace.
  3. write (verified): fill the scaffold with real content. Completes when no TODO marker is left anywhere in the workspace (the generated scripts/steer.py is exempt; you never edit it).
  4. validate (verified): completes only while steer validate . passes in the workspace. Fix warnings and info findings too, or tell the user which one stays and why.
  5. exercise (mandate): install the skill, run it once on a real task, and fix what the run exposes. Mark done after the run, then wrap up as the directive says.

Read the full file on GitHub · 143 lines

Files

What ships with it

6 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. 8d ago First seen · 143 lines · 106 tokens per session scan A 95c782f7064f

Subscribe to this mod's changes

building-skills is a skill published in the GitHub repository bh-rat/steer (7 stars, last pushed 2mo ago), licensed MIT. It adds 106 tokens to every session and 1,708 once invoked, about $0.0005 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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