contexture web.instructions.md

A set of web development rules for HTML, CSS, and React or similar user-interface files. It covers asynchronous work, code layers, state, network communication, and visual components.

In plain words
What is it for?
Use it when editing web pages or front-end applications that make network requests or manage application state. It guides how to organize code and handle asynchronous operations safely.
Why use it?
It gives coding agents consistent boundaries for handling delayed work, errors, cancellation, and dependencies. This helps avoid common web-app bugs and keeps business logic separate from the interface.

Instructions file for GitHub Copilot

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 instructions/ackeskin/contexture/web
Clone the repo
git clone --depth 1 https://github.com/AcKeskin/contexture

Made for: GitHub Copilot.

Per session 505 This file is loaded in full into every session.
When invoked 505 The same file — it is already loaded in full.
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 $0.00505 $0.00505
Opus 5 $0.00253 $0.00253
Sonnet 5 $0.00101 $0.00101
Haiku 4.5 $0.00051 $0.00051

Measured yesterday against content hash 8240fd2b73d4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

contexture web.instructions.md 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 yesterday.

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.

.github/instructions/web.instructions.md · 40 lines

How it starts

The opening of the file, as written. The whole thing — 40 lines — stays where its author put it; the contents beside it link to each section on GitHub.

web rules

Auto-loaded by Copilot when editing files matching **/*.{html,css,jsx,tsx}. Generated from architectural-rules/web/ — do not hand-edit.

Web async discipline

  • All async work is explicit. async/await at call sites, not fire-and-forget.
  • No implicit side effects in render / effect hooks beyond what the contract allows (e.g. React useEffect cleanup).
  • Cancelation is part of the design — every long-running async operation has a cancel path (AbortController, effect cleanup, subscription disposal).
  • Errors in async work are handled explicitly. Unhandled promise rejections are bugs, not warnings to ignore.

Why: async bugs dominate production incidents in web apps. Explicit patterns catch them at review time. Source: MDN AbortController; WHATWG HTML unhandledrejection.

Web layering

  • Four layers, strict dependencies inward:
    • Domain — pure business logic, framework-agnostic.
    • State — application state shape, reducers / stores.
    • Transport — HTTP, WebSocket, other I/O adapters.
    • UI — presentation, framework components.
  • Domain must have no React / Vue / Angular / framework imports.
  • UI talks to State; State talks to Transport; Transport talks to Domain types (not the other way).
  • Avoid magic globals. No module-level mutable state.
  • This vocabulary refines universal/layering for web apps: Domain = Core, Transport = Integration, UI = UI; State is web's extra layer between UI and Transport (Platform rarely appears). Universal/layering owns the base vocabulary.

Why: frameworks churn. Domain logic bound to framework primitives dies with the framework. Source: ports-and-adapters / clean-architecture layering.

Web state flow

  • State flow is predictable: state in → render out → action → state in. Unidirectional.
  • No magic globals. No window.* mutation for app state.
  • State changes are explicit and traceable — every change has an identifiable source (action, event handler, effect).
  • Prefer derived state over duplicated state. If two pieces of state can disagree, one is wrong.

Read the full file on GitHub · 40 lines

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. yesterday First seen · 40 lines · 505 tokens per session scan A 8240fd2b73d4

Subscribe to this mod's changes

contexture web.instructions.md is an instructions file published in the GitHub repository AcKeskin/contexture (2 stars, last pushed 1mo ago), licensed MIT. It adds 505 tokens to every session, about $0.0025 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 2026-08-31.