Claude.ai and Cowork

Mastering Claude.ai: Projects and artifacts

Beyond plain chat, Claude.ai has two tools beginners often miss.

Projects: a space that holds a persistent context (custom instructions + knowledge documents) reused across all the project's conversations. Instead of re-pasting your brief every time, you put it once in the project. It is the consumer equivalent of a CLAUDE.md.

Artifacts: when Claude produces a self-contained deliverable (a document, a piece of code, an HTML page, a table), it opens it in a separate panel, editable and versioned, next to the conversation. You can iterate on it without drowning the chat.

Good habits:

• Put your recurring instructions (tone, language, format, constraints) in the Project instructions, not in each message.
• Load your reference documents into the Project's knowledge base.
• Use artifacts for anything that is a deliverable, not a discussion.

Claude Cowork: the digital coworker

Cowork is Anthropic's agentic mode in the desktop app, generally available since April 2026. You give Claude access to specific folders on your machine and instructions in plain language; it reads, edits, creates and organizes files, plans and executes multi-step tasks, in the background.

Built on the same foundations as Claude Code, but designed for non-technical knowledge workers. Typical examples:

• Filling out an expense report from receipt photos.
• Writing a report from scattered notes.
• Reorganizing a messy folder by a logic you describe.
• Synthesizing several sources into one deliverable, without you coordinating each step.

The key difference from chat: Cowork acts on your file system, it does not just answer. It is the same shift as chat to Claude Code, but for office files rather than code.

Connectors, Scheduled Tasks, Computer Use, RBAC

The Cowork/Claude ecosystem gained several building blocks in 2026:

• Connectors: link Claude to external services (drive, calendar, mail, business tools) so it can read and act beyond your local files. Technically, these are MCP servers (module 5).
• Scheduled Tasks: run a task at a fixed time (a report every Monday, a daily watch). Pierre uses them for nightly memory consolidation and refreshing his prompt corpus.
• Computer Use: Claude drives a graphical interface (mouse, keyboard, screen) for tasks that have no API. Powerful but to be supervised.
• RBAC (role-based access control): on the enterprise side, define who can do what with the agents. Shipped with Cowork's GA.
• Dispatch and Projects: delegate sub-tasks and carry persistent context, as in the chat.

The cross-cutting idea: Claude does not stay in its dialog box. Connectors, scheduled tasks and computer use give it hands in your real environment.

Projects in depth

A Project in Claude.ai is a persistent workspace that holds three things together: a set of uploaded files (called project knowledge), a block of custom instructions, and the full history of every conversation you start inside it. Unlike a plain chat, which forgets everything the moment you close it, a Project keeps its context alive indefinitely, so every new chat you open inside the Project already "knows" your documents and rules.

Project knowledge is the library Claude reads before answering. You upload files (PDFs, text files, spreadsheets, code) or paste raw text directly. Claude indexes that content and can quote, summarise, or reason over it in any conversation inside the Project. Good candidates for project knowledge include:

• Company style guides or brand voice documents
• Product specs, FAQs, or pricing sheets
• Recurring reference data (glossaries, org charts, templates)
• Previous research you want Claude to build on

Custom instructions are a standing system prompt (a set of rules injected before every conversation) that you write once and never repeat again. Use them to set the tone ("always reply in British English"), define Claude's role ("you are a senior copywriter for a B2B SaaS company"), or enforce constraints ("never recommend competitors"). Instructions in a Project override the global custom instructions you may have set in your account settings, so you can have different personas for different Projects.

Because knowledge and instructions persist, Projects are the right tool whenever you have a recurring workflow: a weekly report, a client account, a research topic, or a product you support. Opening a new chat inside an existing Project costs you nothing in setup time, and Claude picks up exactly where the shared knowledge left off.

Custom instructions and styles

Both Claude.ai (the chat interface) and Claude Cowork (the desktop file agent) let you define custom instructions: a block of text Claude reads silently before every conversation. Think of it as a permanent briefing you write once, so you never have to repeat yourself.

In Claude.ai, open your profile and find Custom Instructions. You can tell Claude your role, preferred language register, output format, and things to avoid. In Claude Cowork, the equivalent lives in the project settings panel under Project Instructions. Both support plain prose and bullet lists.

Good custom instructions cover four areas:

• Role context: who you are and what you do ("I manage marketing for a B2B industrial equipment company").
• Tone and register: formal, casual, technical depth expected.
• Format preferences: bullet lists vs prose, short paragraphs, no em-dashes, no filler phrases.
• Hard constraints: things Claude must never do ("never invent statistics, never use exclamation marks").

Once saved, every new chat inherits these rules automatically. You can override them for a single session by simply telling Claude in that conversation, but the saved instructions stay unchanged for next time.

Artifacts you can share

When you ask Claude.ai to produce a document, a block of code, or a small interactive app, the result appears in a dedicated panel called an artifact. The artifact sits beside the conversation rather than inside it, so you can read, copy, or interact with it without losing track of the chat.

Three kinds of artifact exist. A document artifact holds formatted text such as a report, a contract draft, or a how-to guide. A code artifact shows syntax-highlighted source code you can copy in one click. A mini-app artifact (also called a rendered artifact) runs live HTML, CSS, and JavaScript directly in the browser, letting you see a working calculator, a quiz, or a chart without leaving the page.

Every artifact comes with a Share button. Clicking it produces a public link anyone can open, even without a Claude account. The recipient sees the artifact in a clean viewer and can interact with mini-apps as if they built it themselves. You can also remix a shared artifact: open the link, click Remix, and Claude starts a new chat pre-loaded with that artifact ready to edit.

• Document: markdown or rich text, ideal for reports and templates.
• Code: any language, copyable with one click, not executed in the browser.
• Mini-app: live HTML/JS, runs in the artifact panel, shareable as an interactive link.
• Remix: opens a shared artifact into a fresh Claude chat for further editing.

Cowork: acting on your files

Claude Cowork is the desktop agent that can read, edit, create, and organize files that actually live on your computer. Unlike Claude.ai (the chat interface in your browser), Cowork has direct access to your local file system, which means you can ask it to work inside a folder full of documents without copying and pasting anything.

When you open Cowork and point it at a folder, Claude reads the files you share with it and can take file actions: rewriting a paragraph, renaming files, creating a new document from a template, or moving items into subfolders. Every action is shown to you before it is applied, so you stay in control.

Common things Cowork handles well:

• Summarizing or rewriting a long Word or PDF document
• Creating a new file based on your instructions (drafts, reports, templates)
• Renaming or reorganizing a batch of files according to a naming rule you describe
• Searching across multiple documents to find a specific piece of information
• Comparing two versions of a file and listing the differences

Cowork is not a code editor and not a terminal (that is Claude Code, the command-line tool for developers). Cowork is built for everyday file work: writing, editing, and organizing content on your machine.

Cowork: planning multi-step tasks

Claude Cowork (the desktop file agent) does not just answer a single question. When you give it a complex goal, it first builds a plan: an ordered list of steps it intends to take before touching anything on your computer. You can read the plan and approve it before execution begins.

Each step in the plan is a discrete action, such as reading a file, creating a folder, writing new content, or running a search. Cowork chains these actions one after another, checking its own output at each stage before moving to the next. This loop is called an agentic sequence (a series of decisions made autonomously by the model).

Two safety mechanisms protect you during a long sequence:

• Confirmation gates: Cowork pauses before irreversible actions (deleting, overwriting) and asks for your go-ahead.
• Context tracking: the model keeps a running summary of what it has already done so later steps can depend on earlier results without re-reading everything.

If a step fails (a file is missing, a permission is denied), Cowork reports the error, explains what it tried, and either suggests a fix or asks you how to proceed. It does not silently skip steps.

Connectors: Gmail, Drive, Calendar

A connector is an authorized link between Claude and an external service such as Gmail, Google Drive, or Google Calendar. Once wired up, Claude can read and act on real data from those services inside the same conversation, without you copying and pasting anything.

You set connectors up inside Claude.ai under Settings, then Integrations. Each connector asks you to sign in with the relevant account and grant specific permissions. Claude only uses those permissions when you explicitly ask it to in a conversation. Nothing is accessed in the background.

Here is what each connector unlocks:

• Gmail: read threads, draft replies, summarize inbox, find a specific email by topic or sender.
• Google Drive: open documents, spreadsheets, or PDFs stored in your Drive and reason over their content.
• Google Calendar: read upcoming events, find free slots, draft event descriptions, and spot scheduling conflicts.

Connectors work through OAuth (Open Authorization), the standard protocol that lets you grant access without giving Claude your password. You can revoke a connector at any time from the same Settings page, and Claude instantly loses access to that service.

Computer Use, done safely

Computer Use is a Claude capability that lets the model control a real computer: it can move the mouse, click buttons, type text, read the screen, and execute programs, all on its own. Instead of just answering questions, Claude becomes an agent (an AI that takes actions) that drives software the way a human would.

That power comes with real risks. Because Claude can run arbitrary commands and browse the web, a malicious website or a crafted file could trick it into doing something harmful. This class of attack is called prompt injection: hidden instructions in external content hijack the agent mid-task. Other risks include accidental data deletion, unintended purchases, or leaking credentials if the agent has access to a logged-in browser session.

The recommended defense is sandboxing: running Computer Use inside an isolated environment so that any damage is contained. Common sandbox options include:

• Docker container: a lightweight isolated Linux box. The agent acts inside it; your real system is untouched.
• Virtual machine (VM): a fully separate OS instance, stronger isolation than a container.
• Cloud sandbox: a short-lived remote desktop spun up for one task then discarded (for example, the reference implementation Anthropic ships with the Computer Use API).
• Minimal permissions: even inside a sandbox, give the agent only the accounts and folders it truly needs for the task.

Computer Use is accessed through the Anthropic API (the programming interface), not through Claude.ai chat. You pass special computer-use tools in your API request: computer, text_editor, and bash. Claude then returns tool-call actions which your code executes and feeds back as screenshots. The best current model for Computer Use is claude-opus-4-8, which has the strongest reasoning for multi-step GUI tasks.

Claude on mobile and by voice

The Claude.ai mobile app (iOS and Android) brings the full conversational model to your phone. You can type, paste text, share images from your camera roll, and upload documents. The interface adapts to small screens, so long responses are paginated and easy to scroll.

Voice input lets you dictate your prompt using your phone's built-in microphone, then read Claude's reply on screen. This is not a true voice-to-voice assistant: Claude receives your transcribed text and returns written text. It shines for hands-free drafting, quick questions while commuting, or when typing is inconvenient.

Mobile Claude is best for tasks that fit in a single exchange or a short back-and-forth. It is not designed for long coding sessions or file-heavy workflows. Those belong in Claude Code (the CLI and IDE agent) or Claude Cowork (the desktop file agent). On mobile, stick to writing, brainstorming, summarizing, translating, and light research.

• Strengths on mobile: quick questions, voice dictation, image analysis (describe a photo, read a receipt), translation on the go, and drafting short messages.
• Limitations on mobile: no terminal, no file system access, no multi-step coding pipelines, no persistent memory beyond the current conversation (unless a Project is open).
• Projects on mobile: if you created a Project on Claude.ai, you can continue it on mobile and the project context (instructions, uploaded files) carries over.
• Model choice: the mobile app lets you select the model. Opus (claude-opus-4-8) gives the deepest reasoning; Sonnet (claude-sonnet-4-6) balances speed and quality for everyday use.