deduplicate-rules

A rule for keeping personal Cursor rules separate from project rules. It checks whether a new personal rule repeats or conflicts with a rule stored in the current project.

In plain words
What is it for?
Use it when creating or changing files in your personal Cursor rules folder. It compares them with the workspace's project rules and asks what to do when topics overlap.
Why use it?
It helps prevent duplicate or contradictory instructions. You can choose whether to remove the overlapping project rule or keep both with a note.

Cursor rule

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/cdbattags/ai/deduplicate-rules
Clone the repo
git clone --depth 1 https://github.com/cdbattags/ai
Per session 330 This file is loaded in full into every session.
When invoked 330 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 $0.00330 $0.00330
Opus 5 $0.00165 $0.00165
Sonnet 5 $0.00066 $0.00066
Haiku 4.5 $0.00033 $0.00033

Measured 2d ago against content hash aeee23a2f831, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

deduplicate-rules 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 2d 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.

src/rules/deduplicate-rules.mdc · 38 lines

What it actually says

Deduplicate User vs Project Rules

When creating or modifying a user-level rule (~/.cursor/rules/*.mdc), always check for overlapping project-level rules (.cursor/rules/*.mdc in the workspace).

Workflow

  1. Before writing a user-level rule, scan the current workspace's .cursor/rules/ for rules covering the same topic.
  2. If overlap is found, warn the user:
    • Name the overlapping project-level rule file
    • Explain what it covers vs what the new user-level rule covers
    • Ask whether to delete the project-level rule
  3. If the user confirms, delete the project-level rule.
  4. If the user declines, leave both but note the overlap in the user-level rule with a comment.

What Counts as Overlap

  • Same topic (e.g., both about "no sleep commands")
  • Subset coverage (project rule is a subset of the broader user rule)
  • Conflicting guidance (project rule says X, user rule says Y)

Example

Creating user rule: ~/.cursor/rules/no-sleep-process-monitoring.mdc

Found overlapping project rule:
  .cursor/rules/no-sleep-commands.mdc
  (covers the same topic: avoiding sleep in shell commands)

The user-level rule supersedes the project-level one.
Delete .cursor/rules/no-sleep-commands.mdc? [ask user]
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. 2d ago First seen · 38 lines · 330 tokens per session scan A aeee23a2f831

Subscribe to this mod's changes

deduplicate-rules is a cursor rule published in the GitHub repository cdbattags/ai (4 stars, last pushed 6mo ago), licensed MIT. It adds 330 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 2026-08-31.