skill-creator

skill-creator is a skill for Claude Code, Codex from daymade/claude-code-skills. It costs 208 tokens per session (42,326 once invoked), scanned E, original, MIT.

A process for creating, improving, and testing instruction packages for AI assistants. It treats a skill as a set of instructions and supporting resources designed for a specific type of task.

In plain words
What is it for?
Use it to create a new skill, refine an existing one, choose an appropriate level of testing, and run evaluations when needed.
Why use it?
It helps turn vague improvements into focused edits and checks whether the changed instructions produce better results.

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/daymade/claude-code-skills/skill-creator
Any agent
npx skills add daymade/claude-code-skills --skill skill-creator
Clone the repo
git clone --depth 1 https://github.com/daymade/claude-code-skills

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 skill-creator

README.md
[![agentmods](https://agentmods.dev/badge/skills/daymade/claude-code-skills/skill-creator.svg)](https://agentmods.dev/skills/daymade/claude-code-skills/skill-creator)
Your own site
<a href="https://agentmods.dev/skills/daymade/claude-code-skills/skill-creator"><img src="https://agentmods.dev/badge/skills/daymade/claude-code-skills/skill-creator.svg" alt="Measured on agentmods" height="20"></a>
Per session 208 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 42,326 The whole file, excluding the scripts and references it only reads on demand.
Security scan E 5 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 $0.00208 $0.42326
Opus 5 $0.00104 $0.21163
Sonnet 5 $0.00042 $0.08465
Haiku 4.5 $0.00021 $0.04233

Measured 4d ago against content hash 6b3817f881e2, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade E, and why

skill-creator scanned grade E with 5 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 4d ago.

The scan reads SKILL.md. This mod also ships 29 executable files (eval-viewer/generate_review.py, scripts/__init__.py, scripts/aggregate_benchmark.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.

Tells the agent never to refusehighAnti-refusal

Suppressing the ability to decline removes a core safety control; a later harmful request then succeeds.

- Accept the user's choice — nudge on tradeoffs but never refuse to proceed

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

find -L ~/.claude/plugins/cache -path '*<skill>*' -name '*.md' # -L: installs are often symlinks

Enumerates other installed skillsmediumAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

ls -la ~/.claude/skills/<name> # a symlink into the repo? -> edits are live already

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

| 8 | **npm / PyPI** | SDK or CLI packages | `npm search <keyword>` or `curl https://pypi.org/pypi/<name>/json` |

Runs shell commandslowCapability

Expected in a hook, worth knowing in a rule or an instructions file.

base=json.loads(subprocess.run(['git','show','origin/main:<manifest>'],capture_output=True,text=True).stdout)
daymade-skill/skill-creator/SKILL.md · 1,824 lines

How it starts

The opening of the file, as written. The whole thing — 1,824 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Creator

A skill for creating new skills and iteratively improving them.

At a high level, the process of creating a skill goes like this:

  • Decide what you want the skill to do and roughly how it should do it
  • Classify the change into the lowest verification tier that can falsify its likely failure modes
  • Write a draft of the skill
  • Validate with the smallest evidence that can falsify the changed behavior; treat the full paired eval pipeline as separately authorized work, not an automatic consequence of a tier label
  • Help the user evaluate qualitative or quantitative results when the selected tier produces them
  • Rewrite the skill based on feedback from the user's evaluation of the results (and also if there are any glaring flaws that become apparent from the quantitative benchmarks)
  • Repeat until you're satisfied
  • Escalate the verification tier only when the current evidence cannot resolve the changed behavior

Your job when using this skill is to figure out where the user is in this process and then jump in and help them progress through the applicable stages. Full A/B benchmarking is a capability, not a tax on every edit. Words such as "optimize", "improve", or "comprehensive" describe intent, not failure surface or evaluation budget. Do not create eval files, fan out paired agents, grade outputs, or launch a viewer merely because a task sounds broad or a long conversation precedes it.

Six standing disciplines apply throughout, because these failure modes ship convincing-looking skills that are wrong:

  1. Verify before you write. Every technical assertion that enters the skill (endpoint, parameter, command, version, behavior) must trace to something you executed and observed — in this session or an explicitly approved mined one. Can't verify it right now? Either go verify it, or mark it explicitly ("unverified — from memory"). A skill multiplies whatever it contains: verified knowledge compounds, and so do confidently-stated errors. For knowledge skills (content is mostly facts about an external system — API endpoints, parameters, fields, platform behavior), read references/knowledge-skill-grounding.md for the operational version: the authority ladder (observed behavior > machine-readable contract > exercised production code > official docs > memory), evidence-scope annotation, pre-ship doc-example smoke runs, and the audience/Windows portability checklist. A source-grounding audit once found multiple confident contract claims that contradicted evidence already available to the author (methodology Case 9).
  2. Treat "impossible / not supported" as a hypothesis, not a conclusion. When a capability seems blocked (an API error wall, a tool that won't connect, a format that won't open), exhaust the observation paths — the UI's own network traffic, an alternative channel, a different documented identifier — before writing "the platform doesn't support this" into a skill. Observed behavior outranks speculative request shapes.
  3. Stand on the field's shoulders — retrieve the domain's established best-practices into context BY DEFAULT, before authoring or optimizing a skill's methodology. A skill's methodology is only as good as the knowledge in your context window, not the knowledge latent in your weights: pretraining is lossy, goes stale, and often is not even activated unless the canonical sources are actually pulled in. So the quality ceiling of what you write is your training data + the user's inputunless you deliberately retrieve the subject domain's real prior art. Do it: WebSearch the field's canonical theory / standards / methods, and read any bundled or installed skill in that domain, then fold the load-bearing principles into the skill with attribution. This is a different axis from "Prior Art Research" below — that finds tools/infrastructure to reuse; this grounds the quality of the methodology itself in the discipline's accumulated science. Make it the default action, not something you wait to be asked for: briefly tell the user which field you're pulling from and let them say "skip," but never ship a methodology capped by your memory plus their prompt when 40 years of the field's public work is one search away. Examples: a data-visualization skill must absorb Cleveland & McGill's graphical-perception ranking and Bertin's visual variables (position/length beat color beat text — measured, not aesthetic); a date/time skill must surface the mature libraries and their canonical pitfalls; a persuasion/negotiation skill must retrieve the established frameworks rather than reinvent them from memory. If the canonical knowledge lives only in your weights and never enters context, you are guessing where you could be citing.
  4. Preserve before you compress an existing skill. Updating an existing skill is a migration, not a blank-page rewrite. Before the first edit, capture the complete old bundle with the audit tool's snapshot command, or reconstruct it from an explicit Git ref; an arbitrary copy plus a provenance label is not a baseline. Inventory runtime capabilities, trigger contexts, interfaces, references, and eval coverage. Progressive disclosure and concision authorize moving or deduplicating content; they do not authorize silently deleting behavior. After editing, run scripts/audit_skill_regression.py and classify every unmatched old unit. A runtime contract that survives only in evals/, tests, or an unlinked reference is still lost. Do not call the update complete while any candidate is unclassified or any true gap remains unfixed. The same logic governs reversals, not just deletions, and covers any prior commitment — not only the ones carrying a date and a name: overturning a decision already made is a proposal, never a side effect. Say it out loud and get it accepted. A silent rewrite is worse than a silent deletion, because it destroys the artifact and the evidence that could have caught it in one move — and it blinds every downstream reviewer (see #5).

Read the full file on GitHub · 1,824 lines

Files

What ships with it

60 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. 4d ago First seen · 1,824 lines · 208 tokens per session scan E 6b3817f881e2

Subscribe to this mod's changes

skill-creator is a skill published in the GitHub repository daymade/claude-code-skills (1,375 stars, last pushed yesterday), licensed MIT. It adds 208 tokens to every session and 42,326 once invoked, about $0.0010 per session on Opus 5. A static security scan graded it E with 5 findings (tells the agent never to refuse, reads agent configuration directories, enumerates other installed skills). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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