extending-ui

A set of project rules for adding or changing user-interface features that also need backend support. It covers data models, database migrations, APIs, permissions, and implementation order.

In plain words
What is it for?
Planning and implementing UI features in a .NET application, including entities, database relationships, migrations, CRUD endpoints, data-transfer objects, authentication, and authorization.
Why use it?
It helps developers account for the database and API work behind a UI change instead of changing only the visible screen.

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/elumenotion/guideants/extending-ui
Clone the repo
git clone --depth 1 https://github.com/Elumenotion/GuideAnts

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 2,607 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 $0.02607
Opus 5 $0.00000 $0.01303
Sonnet 5 $0.00000 $0.00521
Haiku 4.5 $0.00000 $0.00261

Measured yesterday against content hash 16771b5bf62c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

extending-ui 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.

src/.cursor/rules/extending-ui.mdc · 365 lines

How it starts

The opening of the file, as written. The whole thing — 365 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rules for Extending UI Features with Backend Changes

1. Analysis Phase

1.1 Feature Scope Assessment

  • Identify the specific UI components that need to be added/modified
  • Determine what data needs to be persisted or retrieved
  • Map out any new user interactions or workflows
  • Identify affected existing components and potential side effects

1.2 Data Model Impact

  • Check if existing entities can support the new feature
  • If new data is needed, determine if it requires:
    • New entity
    • Extension of existing entity
    • New relationships
    • New computed properties
  • Verify cascade delete implications
  • Consider data migration needs

1.3 API Requirements

  • List required CRUD operations
  • Identify new DTOs needed
  • Map authentication/authorization requirements
  • Consider rate limiting needs
  • Plan API versioning impact

2. Implementation Order

2.1 Data Layer Changes

  1. Add/modify entity classes in GuideAntsApi.DataModel
  2. Configure relationships in ApplicationDbContext
  3. Create migration using dotnet ef migrations
  4. Verify migration SQL for unexpected changes
  5. Update any affected repository methods

2.2 API Layer Changes

  1. Create/update DTOs in GuideAntsApi/Models
  2. Add/modify service interfaces and implementations
  3. Configure new endpoints in appropriate endpoint class
  4. Add authorization requirements
  5. Implement validation

2.3 Frontend Changes

  1. Add new types/interfaces in TypeScript
  2. Create/update API client methods
  3. Implement UI components
  4. Add state management code
  5. Implement error handling
  6. Add loading states

3. Required Files to Modify

3.1 Backend Files

GuideAntsApi.DataModel/
  Models/                    # Add/modify entity classes
  ApplicationDbContext.cs    # Configure relationships
  
GuideAntsApi/
  Models/                    # Add DTOs
  Services/                  # Add/modify services
  Endpoints/                 # Add endpoint configurations

Read the full file on GitHub · 365 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 · 365 lines · 0 tokens per session scan A 16771b5bf62c

Subscribe to this mod's changes

extending-ui is a cursor rule published in the GitHub repository Elumenotion/GuideAnts (54 stars, last pushed 9d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 2,607 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.