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 agentmods add skills/catwillgh/mainframe/mainframe-frontendnpx skills add CATWILLgh/MAINFRAME --skill mainframe-frontendgit clone --depth 1 https://github.com/CATWILLgh/MAINFRAMEWrote 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/catwillgh/mainframe/mainframe-frontend)<a href="https://agentmods.dev/skills/catwillgh/mainframe/mainframe-frontend"><img src="https://agentmods.dev/badge/skills/catwillgh/mainframe/mainframe-frontend.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00096 | $0.01429 |
| Opus 5 | $0.00048 | $0.00714 |
| Sonnet 5 | $0.00019 | $0.00286 |
| Haiku 4.5 | $0.00010 | $0.00143 |
Grade A, and why
mainframe-frontend 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 3d 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.
This is a copy
91% identical to frontend — 53 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 121 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend engineering
Deliver one coherent user-facing result. Treat React implementation, interaction quality, visual design, accessibility, component reuse, and focused tests as branches of the same frontend task rather than independent products.
Establish the active frontend
- Run
node scripts/recon.js <package-root>, or follow manual recon, before choosing an approach. - Trace the changed user journey through its route, component tree, state, browser boundary, server contract, visible states, and existing tests.
- Preserve the installed framework, rendering model, router, architecture, state, validation, styling, primitives, and visual language unless their migration or redesign is explicitly part of the task.
- Verify installed versions and version-sensitive APIs with current primary documentation or an available authoritative documentation tool.
- Complete the assigned behavior without TODOs, placeholders, disabled or weakened checks, suppressions, or deferred in-scope work.
Several routers, state libraries, validators, or UI systems are observations, not automatic blockers. Resolve the active owner from imports, providers, configuration, runtime wiring, and affected files. Escalate only an unresolved choice that changes product behavior, infrastructure, permission, or the assigned visual direction.
Route only the relevant context
React and browser engineering
| Changed concern | Read |
|---|---|
| Framework, rendering, routing, Server and Client Components | frameworks |
| Module ownership and established architecture | architecture |
| Fetching, mutations, caching, and optimistic UI | data fetching |
| Forms and validation | forms |
| PWA, IndexedDB, offline queues, and realtime | offline and realtime |
| Editors, Markdown, files, tables, charts, and complex interaction | content and data UI |
| Browser trust boundaries, secrets, XSS, and version-sensitive styling | safety |
| Logic, component, browser, and CI test scope | testing |
What ships with it
31 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.
- agents/openai.yaml 209 B
- references/accessibility.md 3.0 KB
- references/architecture.md 1.4 KB
- references/color.md 2.8 KB
- references/content-and-data-ui.md 2.4 KB
- references/data-fetching.md 1.6 KB
- references/design-context.md 2.2 KB
- references/design-workflows.md 2.5 KB
- references/distinctiveness.md 3.6 KB
- references/flows-and-feedback.md 945 B
- references/forms.md 1.5 KB
- references/frameworks.md 1.5 KB
- references/layout.md 1.9 KB
- references/mode-experience.md 883 B
- references/mode-operate.md 879 B
- references/mode-persuade.md 878 B
- references/mode-read.md 811 B
- references/motion.md 2.2 KB
- references/offline-and-realtime.md 1.5 KB
- references/recon.md 1.4 KB
- references/review-and-evidence.md 2.2 KB
- references/safety.md 1.7 KB
- references/shadcn-cli.md 1.5 KB
- references/shadcn-component-map.md 1.1 KB
- references/shadcn-composition.md 1.8 KB
- references/shadcn-forms.md 1.2 KB
- references/testing.md 2.6 KB
- references/type-craft.md 2.7 KB
- references/typography.md 2.3 KB
- scripts/inspect-ui.mjs 2.8 KB runs code
- scripts/recon.js 5.0 KB runs code
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.
- 3d ago First seen · 121 lines · 96 tokens per session scan A abccb93350c9
mainframe-frontend is a skill published in the GitHub repository CATWILLgh/MAINFRAME (2 stars, last pushed 13d ago), licensed MIT. It adds 96 tokens to every session and 1,429 once invoked, about $0.0005 per session on Opus 5. A static security scan graded it A with 0 findings. It is 91% identical to frontend, differing in 53 lines, and is treated as a copy.
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