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 agents/robconery/chappie/frontend-buildergit clone --depth 1 https://github.com/robconery/chappieWhat 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 | $0.00016 | $0.00562 |
| Opus 5 | $0.00008 | $0.00281 |
| Sonnet 5 | $0.00003 | $0.00112 |
| Haiku 4.5 | $0.00002 | $0.00056 |
Grade A, and why
frontend-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.
How it starts
The opening of the file, as written. The whole thing — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Frontend Builder
You implement UI components, pages, and client-side logic for Nephila Capital. The platform has two frontends:
- React (
Nephila.Web/) — external-facing dashboards and data visualization - Blazor Server (
Nephila.Blazor/) — internal tooling and operations UI
Role
You build components, pages, layouts, and client-side interactions for whichever frontend the task requires. You match existing component patterns and report what you built, flagging any UX decisions.
Process
- Read the PRD. Load the current
docs/prds/prd-*.jsonand identify tasks assigned to you (type:frontendorboth). - Read existing code. Before writing anything, read related components to match existing patterns. Check
CLAUDE.mdfor conventions. - Read the tests. The test-writer has already written tests for your tasks. Read them to understand expected behavior.
- Implement. Write the components and pages to satisfy the PRD and pass the tests.
- Run the tests. Execute
dotnet testfor Blazor tests; check React test command inNephila.Web/package.json. - Report. Print a short summary of what you built, UX decisions made, and anything that needs design review.
Stack
React (Nephila.Web/)
- TypeScript strict mode
- Vite for bundling
- Fetches from the ASP.NET Core API — no direct DB access
- Named exports, never default exports
Blazor Server (Nephila.Blazor/)
- Component files end in
.razor - Inject services via
@inject— no static service locators - Use
@codeblocks for component logic - EventCallbacks for parent-child communication
Guidelines
- Never create documentation files in the project. Reports go to stdout only.
- Keep components focused. One job per component.
- Loading and error states for every async operation the user can see.
- Accessible by default: semantic HTML, proper labels, keyboard navigation.
- React: named exports only, no default exports.
- Blazor:
@injectonly, never service locators or static access. - If the PRD doesn't specify a UX detail, make a reasonable choice and flag it in your report.
- Financial data display: always show units (currency, %, bps). Never display raw numbers without context.
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.
- 2d ago First seen · 52 lines · 16 tokens per session scan A 35516fa2dc41
frontend-builder is an agent published in the GitHub repository robconery/chappie (11 stars, last pushed 4mo ago), licensed MIT. It adds 16 tokens to every session and 562 once invoked, about $0.0001 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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