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.
npx agentmods add rules/duckduckgo/apple-browsers/network-quality-testinggit clone --depth 1 https://github.com/duckduckgo/apple-browsersWhat 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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5 | $0.00000 | $0.01016 |
| Opus 5 | $0.00000 | $0.00508 |
| Sonnet 5 | $0.00000 | $0.00203 |
| Haiku 4.5 | $0.00000 | $0.00102 |
Grade A, and why
network-quality-testing 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.
How it starts
The opening of the file, as written. The whole thing — 162 lines — stays where its author put it; the contents beside it link to each section on GitHub.
NetworkQualityMonitor Testing Framework
Overview
The NetworkQualityMonitor is a comprehensive network quality testing framework designed for the DuckDuckGo Privacy Browser. It provides pre-flight network connectivity and performance checks to ensure optimal browser performance.
Architecture Principles
SOLID Design
- Single Responsibility: Each tester handles one specific network metric
- Open/Closed: Protocol-based design allows extension without modification
- Dependency Injection: All dependencies injected for testability
- Interface Segregation: Focused protocols for each test type
Component Structure
NetworkQualityMonitor (Orchestrator)
├── HttpResponseTester (Latency)
├── BandwidthTester (Speed)
├── DNSTester (Resolution)
├── BufferBloatTester (Congestion)
└── NetworkScoreCalculator (Scoring)
Test Implementation Details
HTTP Response Testing (Latency)
- Multi-endpoint sampling: Tests CDN endpoints (CloudFlare, Fastly, CloudFront)
- Statistical analysis: Calculates median, mean, standard deviation, CV
- Smart aggregation: Best site selection with weighted penalties
- Metrics: P50/P95 percentiles, variance, failure rate
Bandwidth Testing
- Server selection: Quick 10MB test, then full test on best servers
- Download measurement: Multiple runs, returns maximum speed
- Upload measurement: Chunked uploads (50MB x 2)
- Optimization: Range requests, cache-busting, timeout protection
DNS Testing
- Domain resolution: Popular domains (google.com, cloudflare.com)
- Timing precision: CFAbsoluteTime for microsecond accuracy
- Failure tracking: Resolution success/failure rates
- System resolver: Uses native DNS resolution
Buffer Bloat Testing
- Baseline measurement: Unloaded network latency
- Load testing: Concurrent downloads during latency measurement
- Grade assignment: A-F based on latency increase percentage
- Real-time impact: Critical for video calls, gaming
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.
- yesterday First seen · 162 lines · 0 tokens per session scan A f618555cb4f3
network-quality-testing is a cursor rule published in the GitHub repository duckduckgo/apple-browsers (252 stars, last pushed yesterday), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 1,016 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 2026-09-01.
Other cursor rules, from other repositories
release-policy
Release, versioning, and signing policy for setmac.
on-load-rule
This guide outlines the critical development principles for this Swift project.
visualization-rule
Creates visual representations of project specifications, tasks, and knowledge.
angular-20
This rule provides comprehensive best practices and coding standards for Angular development, focusing on modern TypeScript, standalone components, signals, and performance optimizations.
dev-standard
Apache Superset development standards and guidelines for Cursor IDE.
cli-error-handling
CLI command error handling patterns.