cursor-rules

Example rules to help Cursor users build better with LaunchDarkly.

This repo ships Cursor project rules as .mdc files. Each file is a small policy Cursor can apply when you work in Agent or Chat, so suggestions stay aligned with good flag and SDK patterns.

Rule file	Intent
using-flags.mdc	Centralized evaluation, context design, fallbacks
implementing-launchdarkly.mdc	SDK wrappers, config, singleton init, shutdown
troubleshooting-launchdarkly.mdc	Debugging and operational guidance

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TL;DR — quick adoption (single monorepo)

For one repo that contains all your apps (open the monorepo root in Cursor):

1. Create /.cursor/rules/ at the repository root (same level as your root package.json / go.work / etc.).
2. Copy using-flags.mdc, implementing-launchdarkly.mdc, and troubleshooting-launchdarkly.mdc from this repo into that folder (keep names and .mdc extension).
3. Commit .cursor/rules/*.mdc so the team gets the same rules.
4. Reload the window or reopen the folder if rules do not show up immediately.

That’s enough for day-to-day use. Verification (Settings UI, alwaysApply / globs, sub-packages) is in the full guide below.

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Full guide

1. Prerequisites

• Cursor installed (rules format targets Cursor’s project rules, not generic Copilot config).
• Your app opened in Cursor as a folder or multi-root workspace (rules apply relative to the workspace).

2. Copy the rule files into your project

From this repository, copy the three .mdc files into your repo:

your-project/
  .cursor/
    rules/
      using-flags.mdc
      implementing-launchdarkly.mdc
      troubleshooting-launchdarkly.mdc

Create .cursor/rules/ if it does not exist. Keep the .mdc extension so Cursor treats them as project rules.

Ways to get the files:

• Download: GitHub → each file → Raw → save with the same name under .cursor/rules/.
• Clone and copy: git clone https://github.com/launchdarkly-labs/cursor-rules.git then copy the three files into your project.
• Submodule (optional): add this repo as a submodule and symlink or copy the .mdc files into .cursor/rules/ (Cursor does not read rules from arbitrary paths outside .cursor/rules/ unless you copy or link them there).

3. Commit them (recommended for teams)

Check .cursor/rules/*.mdc into version control so everyone gets the same guidance:

git add .cursor/rules/*.mdc
git commit -m "chore: add LaunchDarkly Cursor project rules"

4. Verifying rules are active

1. Open Cursor Settings → search for Rules (wording may vary by Cursor version, e.g. Cursor Settings → General → Project rules).
2. You should see your project rules listed; each rule’s description comes from the YAML frontmatter description field in each .mdc file.
3. Start Agent or Chat in a file where LaunchDarkly is relevant; ask something that would touch flags or SDK setup—the model should respect the rule content when it’s included in context.

If a rule has alwaysApply: false (the default in these examples), Cursor may attach it when the task matches the rule’s description or globs. You can set alwaysApply: true in the frontmatter if you want that file’s rules considered for every request in that project (heavier context).

5. (Optional) Scope rules with globs

To limit a rule to certain paths, edit the frontmatter in that .mdc file, for example:

---
description: LaunchDarkly flag usage conventions for application code
globs: src/**/*.ts,src/**/*.tsx
alwaysApply: false
---

Use patterns that match your repo layout. Leave globs empty to rely on description-based inclusion only.

6. Monorepos and multiple apps

• Single monorepo, root opened in Cursor: use one .cursor/rules/ at the repo root (same as the TL;DR above). Rules apply across the tree for that workspace.
• You only open a subpackage as the workspace folder: put .cursor/rules/ inside that package instead (Cursor only loads project rules from the opened root).

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Keeping rules up to date

• Pull updates: Re-copy or merge changes from this repo when the .mdc files change.
• Fork: Fork this repo if your org wants to customize rules and still track upstream.

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References

• Cursor Rules documentation: https://docs.cursor.com/context/rules
• LaunchDarkly documentation: https://docs.launchdarkly.com/

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License

See LICENSE.