webview-conventions

webview-conventions is a cursor rule for Cursor from sthamann/nyx-local-ai. It costs 0 tokens per session (341 once invoked), scanned A, original, MIT.

A set of rules for structuring and updating Nyx's webview, the in-extension user interface shown in a browser-like panel.

In plain words
What is it for?
Use it when adding or changing Nyx interface modules, message types, rendering, security settings, bundled libraries, or harness-based UI checks.
Why use it?
It keeps UI code organized, messages between the extension and interface checked, user content safe, and streaming responses responsive.

Cursor rule for Cursor

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 rules/sthamann/nyx-local-ai/webview-conventions
Clone the repo
git clone --depth 1 https://github.com/sthamann/nyx-local-ai

Made for: Cursor.

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 webview-conventions

README.md
[![agentmods](https://agentmods.dev/badge/rules/sthamann/nyx-local-ai/webview-conventions.svg)](https://agentmods.dev/rules/sthamann/nyx-local-ai/webview-conventions)
Your own site
<a href="https://agentmods.dev/rules/sthamann/nyx-local-ai/webview-conventions"><img src="https://agentmods.dev/badge/rules/sthamann/nyx-local-ai/webview-conventions.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 341 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 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 $0.00000 $0.00341
Opus 5 $0.00000 $0.00170
Sonnet 5 $0.00000 $0.00068
Haiku 4.5 $0.00000 $0.00034

Measured 5d ago against content hash cf050a9957d7, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

webview-conventions 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 5d 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.

.cursor/rules/webview-conventions.mdc · 26 lines

What it actually says

Webview conventions

  • Module boundaries: dom.ts owns the HTML skeleton + element refs, state.ts owns shared state + post(), transcript.ts renders messages and cards, composer.ts owns input/queue/attachments, main.ts is only the host-message dispatcher. New UI belongs in the matching module, not main.ts.
  • All host↔webview messages are typed in src/types.ts (HostToWebview / WebviewToHost). Add the variant there first; the dispatcher switches must stay exhaustive (never check in default).
  • Escape everything user- or model-provided with escapeHtml before innerHTML; markdown goes through renderMarkdown/renderMarkdownFinal.
  • Streaming renders are throttled (see scheduleStreamingRender): never re-parse full markdown on every delta — that froze the UI on long generations once already.
  • No external resources: the CSP allows only bundled assets; libraries (marked, highlight.js) are bundled via esbuild into media/main.js.
  • Verify UI changes in the harness: python3 -m http.server 8321 + http://127.0.0.1:8321/.harness/index.html?scene=chat|approval|machines renders the real bundle with demo data (also used for README screenshots).
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. 5d ago First seen · 26 lines · 0 tokens per session scan A cf050a9957d7

Subscribe to this mod's changes

webview-conventions is a cursor rule published in the GitHub repository sthamann/nyx-local-ai (137 stars, last pushed 2mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 341 tokens. 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.