wasm-constraints

wasm-constraints is a cursor rule for Cursor from sruja-ai/sruja. It costs 321 tokens per session, scanned A, original, Apache-2.0.

A set of rules for Rust code that runs in WebAssembly, a format for running code in web browsers and Node.js. It defines which system features and coding patterns are allowed.

In plain words
What is it for?
Use it when changing Rust files in the WebAssembly part of the project, especially before building or testing browser and Node.js versions.
Why use it?
It helps prevent code from using file access, networking, threads, or other features that WebAssembly builds cannot support.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

Good fit Use it when changing Rust files in the WebAssembly part of the project, especially before building or testing browser and Node.js versions.

Compare 6 cursor rules from other repositories ↓
Install with agentmods
npx agentmods add rules/sruja-ai/sruja/wasm-constraints
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.

Clone the repo
git clone --depth 1 https://github.com/sruja-ai/sruja

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 wasm-constraints

README.md
[![agentmods](https://agentmods.dev/badge/rules/sruja-ai/sruja/wasm-constraints.svg)](https://agentmods.dev/rules/sruja-ai/sruja/wasm-constraints)
Your own site
<a href="https://agentmods.dev/rules/sruja-ai/sruja/wasm-constraints"><img src="https://agentmods.dev/badge/rules/sruja-ai/sruja/wasm-constraints.svg" alt="Measured on agentmods" height="20"></a>
Per session 321 This file is loaded in full into every session.
When invoked 321 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00321 $0.00321
Opus 5 $0.00161 $0.00161
Sonnet 5 $0.00064 $0.00064
Haiku 4.5 $0.00032 $0.00032

Measured 7d ago against content hash 6f60df5e79a9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

wasm-constraints 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 7d 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/wasm-constraints.mdc · 25 lines

What it actually says

WASM Constraints

WASM-only crate constraints. Violations here break browser/Node builds.

Scopes

  • crates/sruja-wasm/**/*.rs

Rules

  1. No native-only APIs: Never use std::fs, std::net, std::process, threads, or blocking I/O. Use wasm_bindgen abstractions.
  2. No println!: Use web_sys::console::log_1 or wasm_bindgen::JsValue for logging.
  3. No std::time::Instant: Use js_sys::Date::now() or web_sys::Performance for timing.
  4. No anyhow: Use wasm_bindgen::JsError or custom error types that implement Into<JsValue>.
  5. Serialize all boundaries: All data crossing the WASM/JS boundary must implement serde::Serialize + serde::Deserialize.
  6. Feature-gate native code: If a function needs both native and WASM paths, use #[cfg(target_arch = "wasm32")] / #[cfg(not(target_arch = "wasm32"))].
  7. Keep exports minimal: Only expose functions intended for JS consumption via #[wasm_bindgen].

Verification

After modifying WASM crates, run:

just wasm-nodejs        # build for Node
just test-wasm          # run wasm-pack tests
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. 7d ago First seen · 25 lines · 321 tokens per session scan A 6f60df5e79a9

Subscribe to this mod's changes

wasm-constraints is a cursor rule published in the GitHub repository sruja-ai/sruja (23 stars, last pushed 7d ago), licensed Apache-2.0. It adds 321 tokens to every session, about $0.0016 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.