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 AI-Riksarkivet/ra-mcp --skill convert-web-appgit clone --depth 1 https://github.com/AI-Riksarkivet/ra-mcpWrote 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/ai-riksarkivet/ra-mcp/convert-web-app)<a href="https://agentmods.dev/skills/ai-riksarkivet/ra-mcp/convert-web-app"><img src="https://agentmods.dev/badge/skills/ai-riksarkivet/ra-mcp/convert-web-app/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.
<a href="https://agentmods.dev/skills/ai-riksarkivet/ra-mcp/convert-web-app"><img src="https://agentmods.dev/badge/skills/ai-riksarkivet/ra-mcp/convert-web-app.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00115 | $0.04643 |
| Opus 5 | $0.00057 | $0.02322 |
| Sonnet 5 | $0.00023 | $0.00929 |
| Haiku 4.5 | $0.00012 | $0.00464 |
Grade A, and why
convert-web-app 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 10d 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- convert-web-app — 100% identical, 1 lines differ
How it starts
The opening of the file, as written. The whole thing — 525 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Add MCP App Support to a Web App
Add MCP App support to an existing web application so it works both as a standalone web app and as an MCP App that renders inline in MCP-enabled hosts like Claude Desktop — from a single codebase.
How It Works
The existing web app stays intact. A thin initialization layer detects whether the app is running inside an MCP host or as a regular web page, and fetches parameters from the appropriate source. A new MCP server wraps the app's bundled HTML as a resource and registers a tool to display it.
Standalone: Browser loads page → App reads URL params / APIs → renders
MCP App: Host calls tool → Server returns result → Host renders app in iframe → App reads MCP lifecycle → renders
The app's rendering logic is shared — only the data source changes.
Getting Reference Code
Clone the SDK repository for working examples and API documentation:
git clone --branch "v$(npm view @modelcontextprotocol/ext-apps version)" --depth 1 https://github.com/modelcontextprotocol/ext-apps.git /tmp/mcp-ext-apps
API Reference (Source Files)
Read JSDoc documentation directly from /tmp/mcp-ext-apps/src/:
| File | Contents |
|---|---|
src/app.ts |
App class, handlers (ontoolinput, ontoolresult, onhostcontextchanged, onteardown), lifecycle |
src/server/index.ts |
registerAppTool, registerAppResource, tool visibility options |
src/spec.types.ts |
All type definitions: McpUiHostContext, CSS variable keys, display modes |
src/styles.ts |
applyDocumentTheme, applyHostStyleVariables, applyHostFonts |
src/react/useApp.tsx |
useApp hook for React apps |
src/react/useHostStyles.ts |
useHostStyles, useHostStyleVariables, useHostFonts hooks |
Framework Templates
Learn and adapt from /tmp/mcp-ext-apps/examples/basic-server-{framework}/:
| Template | Key Files |
|---|---|
basic-server-vanillajs/ |
server.ts, src/mcp-app.ts, mcp-app.html |
basic-server-react/ |
server.ts, src/mcp-app.tsx (uses useApp hook) |
basic-server-vue/ |
server.ts, src/App.vue |
basic-server-svelte/ |
server.ts, src/App.svelte |
basic-server-preact/ |
server.ts, src/mcp-app.tsx |
basic-server-solid/ |
server.ts, src/mcp-app.tsx |
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.
- 10d ago First seen · 525 lines · 115 tokens per session scan A 6e880a4a9c09
convert-web-app is a skill published in the GitHub repository AI-Riksarkivet/ra-mcp (23 stars, last pushed today), licensed Apache-2.0. It adds 115 tokens to every session and 4,643 once invoked, about $0.0006 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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