Use Claude reference files when it needs background information, project instructions when it should follow consistent direction, and a Skill when it should perform a reusable procedure. In Claude.ai, reference files and project instructions belong to a Project; in Claude Code, the comparable persistent guidance is stored in CLAUDE.md files, while Skills provide reusable capabilities. They serve different purposes and can be used together.
Choose by what Claude needs
| Your need | Best fit | What it does |
|---|---|---|
| Claude needs facts or background documents for conversations in a Claude.ai Project | Project knowledge, also called reference files | Makes uploaded documents, text, code, and other material available as context for chats in that Project. Anthropic’s Projects help page describes this feature. |
| Responses in a Claude.ai Project should follow a stable role, tone, or direction | Project instructions | Provides guidance tailored to the Project’s responses. The same Project knowledge and instructions are distinct features. |
| Claude Code should follow project-wide conventions, commands, architecture, or shared workflows | Repository CLAUDE.md |
Provides persistent project guidance that can be shared through version control. |
| Claude Code should follow personal preferences across repositories | User-level ~/.claude/CLAUDE.md |
Applies at the individual user scope rather than being shared as repository guidance. |
| Claude Code should follow organization-wide guidance | Managed CLAUDE.md |
Provides instructions at managed, organization-wide scope. Use managed settings or hooks for technical enforcement. |
| A task calls for a repeatable process or specialized capability | Skill | Packages a reusable procedure; its description should make clear what it does and when it applies. Skills may be invoked by name, and some bundled Skills can be invoked automatically when relevant. |
| A coding rule applies only to particular file types or directories | .claude/rules/ |
Scopes instructions to paths so they need not become irrelevant guidance for the whole repository. |
A quick decision test: Does Claude need information? Put it in reference material. Should it consistently behave a certain way? Put that direction in instructions. Is there a reusable way to do a task? Make it a Skill. This reflects the separate roles described in Claude Code memory and instruction documentation, Claude Code Skills documentation, and Anthropic’s Projects help page.
What belongs in each place
Reference files: the source material
Use Claude.ai Project knowledge for project-specific documents such as source material, briefs, specifications, and prior work that Claude should consult in chats within that Project. Files provide context; they are not a procedure telling Claude how to carry out every task.
Instructions: durable direction
Use Claude.ai Project instructions for a stable role, tone, or Project-level direction. In Claude Code, use CLAUDE.md for guidance such as build commands, coding standards, architecture, naming conventions, and common workflows. Anthropic recommends keeping these instructions short and concrete: “Run npm test before committing” tells Claude what to do more clearly than “Test your changes.”
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#1 Best Overall
- Read Before You Buy — No Video Output: These adapters support charging and USB 2.0 data transfer, but cannot transmit video signals. Except for standard USB webcams (which use USB data only), they are not compatible with HDMI/DisplayPort cables, video-capable USB-C hubs, or docking stations with video output.
- Convert USB-A Ports to USB-C: Designed to connect USB-C earphones, cables, flash drives, card readers, and other USB-C accessories to standard USB-A ports. Plug-and-play with no drivers or software required.
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- 12-Month Warranty: Backed by a 12-month manufacturer warranty for peace of mind. Designed to meet strict quality control standards for reliable everyday performance.
Instructions shape Claude’s behavior; they are not a hard enforcement layer. If a rule must be enforced regardless of Claude’s decision, use an enforcement mechanism such as a managed setting or hook rather than relying on prose alone.
Skills: the reusable procedure
Use a Skill when you want Claude to apply a repeatable sequence of steps or a specialized capability when a matching task comes up. Put the procedure in the Skill and make its description specific enough to signal when it applies. This avoids making general project instructions carry detailed workflows that are only relevant sometimes.
Rank #2
- 5-in-1 USB-C Hub: Experience comprehensive connectivity featuring a Power Delivery input, two USB-A 2.0 ports, a USB-A 3.0 port, and an HDMI port. (Note: The USB-C power delivery input port is only for connecting an external wall charger to power your laptop and cannot power peripheral devices.)
- 90W Pass-Through Charging: Achieve optimal charging with 90W pass-through power to your laptop, supported by a total input of 100W, with the hub reserving 10W for operational efficiency. (Note: Wall charger not included.)
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- What You Get: Anker USB-C Hub (5-in-1, 4K HDMI), welcome guide, 18-month warranty, and our friendly customer service.
Organize Claude Code instructions by scope
Claude Code supports guidance at organization, user, and repository scopes. Choose the narrowest scope that matches who needs the instruction:
- Managed guidance: organization-wide direction.
~/.claude/CLAUDE.md: personal preferences that should apply across projects.- Repository
CLAUDE.md: conventions and workflows the project team should share, typically through version control. .claude/rules/: instructions that apply only to specified paths, useful in larger repositories with different requirements for different areas.
Local project instructions can hold personal preferences that should not be shared with the repository. According to Anthropic’s memory documentation, ancestor instruction files load when Claude Code starts, while subdirectory instructions can load when Claude reads files there.
Rank #3
- Sleek 7-in-1 USB-C Hub: Features an HDMI port, two USB-A 3.0 ports, and a USB-C data port, each providing 5Gbps transfer speeds. It also includes a USB-C PD input port for charging up to 100W and dual SD and TF card slots, all in a compact design.
- Flawless 4K@60Hz Video with HDMI: Delivers exceptional clarity and smoothness with its 4K@60Hz HDMI port, making it ideal for high-definition presentations and entertainment. (Note: Only the HDMI port supports video projection; the USB-C port is for data transfer only.)
- Double Up on Efficiency: The two USB-A 3.0 ports and a USB-C port support a fast 5Gbps data rate, significantly boosting your transfer speeds and improving productivity.
- Fast and Reliable 85W Charging: Offers high-capacity, speedy charging for laptops up to 85W, so you spend less time tethered to an outlet and more time being productive.
- What You Get: Anker USB-C Hub (7-in-1), welcome guide, 18-month warranty, and our friendly customer service.
Keep information, direction, and procedures separate
- Put documents Claude needs to consult in Claude.ai Project knowledge, or use relevant project files as appropriate in Claude Code.
- Put durable rules and context in instructions: commands, architecture constraints, conventions, and broad workflows.
- Put a reusable, task-specific sequence of steps in a Skill, with a clear description of its trigger.
- Use scoped rules for guidance that only applies in particular repository paths.
- Use a technical control, not an instruction paragraph, when compliance must be enforced.
This separation reduces duplicated material: instructions can point Claude toward the right process without copying an entire source library, and a Skill can hold its procedure without burdening every unrelated task.
Claude.ai Projects and Claude Code are different
Claude.ai Project knowledge and project instructions apply to conversations in a Claude.ai Project. Claude Code’s CLAUDE.md files and Skills are mechanisms used in the coding environment. Uploading a document to a Claude.ai Project does not create a Skill or alter instruction files in a local code repository.
Rank #4
- Dual Converters, Infinite Potential：Includes 2× USB C male to USB A female adapters and 2× USB A male to USB C female adapters. Perfect for a wide range of uses—tablets with Bluetooth keyboards, expand USB ports on macbook, and more. Two different converters for all your daily needs
- Next-Level 10Gbps & 3A Charging: No more slow 480Mbps, this usb to usb c adapter has a transfer speed of up to 10Gbps, allowing you to do more transferring in less time. This usb adapter fits both USB A and USB C charger, supporting up to 3A fast charging
- Upgraded Exquisite Craftsmanship: With an aluminum alloy housing and metal connector, the usbc to usb adapter is extremely durable and sturdy. Rigorously tested to withstand more than 10,000 times of plugging and unplugging, ensuring long-lasting performance
- Broad Compatible: The usb c to usb adapter widely supports all USB C/ USB A devices like laptops, tablets, cellphones, car chargers, and phone chargers. Such as compatible with MacBook Pro/Air 2023/2022, Thunderbolt 4/3 Devices,Apple MagSafe Watch 9/8/7/SE/Ultra, iPad Pro 2022/2021, Samsung Galaxy S23/S20/S10, and iPhone 17/16/15 Pro. Plug and play
- Please Note: To reach 10Gbps speed, keep the cable under 3.3 ft. For USB A Male to USB C adapters, try flipping the USB C connector. USB C Male to USB A adapters support bidirectional 10Gbps transfer within 3.3 ft
Anthropic’s Help Center says enhanced Project knowledge with retrieval-augmented generation (RAG) is available on paid plans—Pro, Max, Team, or Enterprise—and says capacity can expand by up to 10× when Project knowledge approaches context limits. This is Anthropic’s product-capacity claim, not an independent benchmark or a comparison of the effectiveness of reference files, Skills, and instructions. Plan features can change, so check the current Help Center details for availability.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Using an existing AGENTS.md with Claude Code
Claude Code documentation describes support for reading AGENTS.md as project instructions, but default loading depends on whether CLAUDE.md or CLAUDE.local.md is present and on the Project instructions setting. Anthropic documents direct support for Claude Code v2.1.277 or later and notes that some sessions may not support it. Check /config and the installed version if loading behavior matters. When compatibility is uncertain, Anthropic documents importing AGENTS.md from CLAUDE.md. See the memory documentation for instruction-file behavior and settings documentation for configuration.
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Best Value
- 5-in-1 Connectivity: Equipped with a 4K HDMI port, a 5 Gbps USB-C data port, two 5 Gbps USB-A ports, and a USB C 100W PD-IN port. Note: The USB C 100W PD-IN port supports only charging and does not support data transfer devices such as headphones or speakers.
- Powerful Pass-Through Charging: Supports up to 85W pass-through charging so you can power up your laptop while you use the hub. Note: Pass-through charging requires a charger (not included). Note: To achieve full power for iPad, we recommend using a 45W wall charger.
- Transfer Files in Seconds: Move files to and from your laptop at speeds of up to 5 Gbps via the USB-C and USB-A data ports. Note: The USB C 5Gbps Data port does not support video output.
- HD Display: Connect to the HDMI port to stream or mirror content to an external monitor in resolutions of up to 4K@30Hz. Note: The USB-C ports do not support video output.
- What You Get: Anker 332 USB-C Hub (5-in-1), welcome guide, our worry-free 18-month warranty, and friendly customer service.
What the available evidence does not show
Anthropic’s official feature documentation explains how these mechanisms work, but it does not establish which one produces better answers, saves more time, or improves accuracy by a measurable amount. Choose by function and scope rather than assuming a performance advantage. The “up to 10×” capacity statement applies to enhanced Project knowledge under the stated conditions; it is not a measure of Skill or instruction effectiveness.
Quick Recap
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