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.
npx skills add Arenukvern/mcp_flutter --skill skill-authoring-lifecyclegit clone --depth 1 https://github.com/Arenukvern/mcp_flutterWrote 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.
[](https://agentmods.dev/skills/arenukvern/mcp_flutter/skill-authoring-lifecycle)<a href="https://agentmods.dev/skills/arenukvern/mcp_flutter/skill-authoring-lifecycle"><img src="https://agentmods.dev/badge/skills/arenukvern/mcp_flutter/skill-authoring-lifecycle.svg" alt="Measured on agentmods" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 3 findings, 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 MCP Rug Pull · line 23 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 86 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
- medium MCP Rug Pull · line 126 npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.Fix: Pin the version: npx @scope/[email protected]
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00055 | $0.01529 |
| Opus 5 | $0.00028 | $0.00764 |
| Sonnet 5 | $0.00011 | $0.00306 |
| Haiku 4.5 | $0.00006 | $0.00153 |
Grade B, and why
skill-authoring-lifecycle scanned grade B with 1 finding 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.
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.
Recursive force deletemediumDestructive command
rm -rf with a variable or a broad path is one typo away from removing the wrong tree.
1. Safely `rm -rf` the old skill directory. Downgraded: this mod is about security review, or the phrase is quoted, so it is likely naming the pattern rather than instructing it.
How it starts
The opening of the file, as written. The whole thing — 132 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill authoring lifecycle
Add, review, and validate an installable skill package under skills/ in the Skill Steward marketplace.
When to use
- User wants a new skill in this repo
- "Review this skill" or "Is this SKILL.md valid?"
- Bootstrapping
SKILL.mdfornpx skillscompatibility - PR touches
skills/*/SKILL.md
Phase 1: Creation Workflow
- Verify intent — Does the intent overlap with an existing skill? Merge into an existing skill if they serve the same high-level goal or are two halves of the same lifecycle (ADR 0016).
- Collect examples — Write 2–3 concrete user prompts that should trigger the skill and 1 prompt that should not. Skip only when the request already supplies clear usage patterns.
- Plan resources — Decide whether the skill needs instructions only,
scripts/for repeated or fragile operations,references/for detailed knowledge, orassets/for templates/static files. - Choose a name —
kebab-case, 1–64 chars, matches Agent Skills rules (seedocs/STANDARDS.mdx). - Create directory —
skills/{name}/(directory name must equalnamein frontmatter). - Copy template — from
templates/skill/SKILL.md; replace placeholders. - Write description — one concise block covering what and when (trigger phrases users say). Activation-critical routing belongs here, not only in a body "When to use" section.
- Cite sources — create
references/sources.mdfromtemplates/skill/references/sources.md; add rows for every spec/repo/paper used. - Write body — numbered steps, examples, output format; keep under 500 lines.
- Evals — T1 behavior-critical skills (see STANDARDS):
references/evals.md+ ≥2evals/cases/*.yaml. Others: optionalevals.md. - Optional metadata — add
agents/openai.yamlonly when Codex app UI metadata, invocation policy, or tool dependencies are useful. - Optional resources — create only the needed
scripts/,references/, andassets/directories; delete placeholder resources. - Register skill:
- Add skill id to
skills.sh.jsonusing the current repo schema. - Add row to root
README.mdskill table.
- Forward-test tricky skills — For broad or fragile workflows, use a fresh subagent/thread with a natural user prompt and raw artifacts. Do not leak the intended answer, suspected bug, or planned fix into the validation prompt.
What ships with it
4 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.
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.
- 8d ago First seen · 132 lines · 55 tokens per session scan B aaff5a904206
skill-authoring-lifecycle is a skill published in the GitHub repository Arenukvern/mcp_flutter (373 stars, last pushed 13d ago), licensed MIT. It adds 55 tokens to every session and 1,529 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other skills, from other repositories
at_client_skills-sdk
Use this skill when a developer is building a Dart or Flutter app that depends on atclient or atclientflutter from pub.dev, stores or shares data via the Atsign Protocol, needs onboarding (CRAM new-atsign, atKeys file, keychain, APKAM) or APKAM enrollment, or asks about AtCollection , CItem , Query , sub-collections…
flutter-pre-caching
Use when preloading fonts, asset/network images, Lottie/Rive animations, local JSON/config, warming initial API data, or optimizing Flutter Web startup.
firebase-auth
Use when setting up auth, managing auth state, implementing email/password or social sign-in, handling auth errors, or managing users.
architecture-feature-first
Use when creating a feature, designing folder structure, adding repositories/services/view models, wiring dependency injection, or deciding which layer owns logic.
code-review
Use when asked to review a PR, MR, branch, or diff, audit changed files, or check code quality.
effective-dart
Use when writing Dart code, reviewing for style, refactoring naming, adding doc comments, structuring imports, or enforcing type annotations.