What is Claude and how it can help you be more productive
Claude isn’t just Anthropic’s cautious answer to ChatGPT anymore. What launched in March 2023 as a safety-focused chatbot from a lab founded by ex-OpenAI researchers has grown into a full agentic platform: a conversational assistant, a terminal-based coding agent, a desktop coworker that reaches into your files, and a shared teammate that lives inside Slack. In July 2026 Anthropic shipped Claude Opus 5 — its fourth model release in under two months.
In this guide we explain what Claude is in 2026, how the Fable 5, Mythos 5, Opus 5, Sonnet 5, and Haiku 4.5 model family works, what Claude Code, Cowork, and Claude Tag can do, what the plans cost, and how to use Claude well.
What is Claude?
Claude is Anthropic’s family of AI models, along with the assistant products built around them. Anthropic was founded in January 2021 by siblings Dario Amodei (CEO) and Daniela Amodei (President), together with five other researchers who left OpenAI over how much weight safety should carry in frontier AI development. The company is structured as a Public Benefit Corporation, and its signature training method, Constitutional AI, steers models to follow a written set of principles rather than relying purely on human raters to shape behavior after the fact.
Claude reached the public on March 14, 2023, as Claude 1 and Claude Instant, offered through Anthropic’s API before ChatGPT had even marked its first birthday. What has changed since then is almost everything around that original model: extended thinking, a 1-million-token context window, computer use, native file creation, memory, dozens of connectors, and three separate agentic products that let Claude act instead of only advise.
Today, depending on the plan and the surface, Claude can:
- Answer questions & explain concepts
- Search the live web & cite sources
- Reason step by step with extended thinking
- Write and edit documents in Artifacts
- Create Excel, PowerPoint & PDF files
- Analyze data and run code
- See and control a computer
- Write, test & ship code as an agent
- Remember context via Memory
- Work across Slack, Drive, Gmail & more
Claude 5: Fable, Mythos, Opus, Sonnet, and Haiku
Claude’s current generation carries the “5” name for its two newest tiers — Sonnet 5 (June 30, 2026) and Opus 5 (July 24, 2026) — while a Mythos-class tier above Opus, made up of Claude Fable 5 and Claude Mythos 5, launched a few weeks earlier on June 9, 2026. As with rivals, Claude.ai mostly assigns a model for you by plan, with a picker when you want to choose by hand.
Behind this sit the still-supported Opus 4.8, 4.7, 4.6, and Sonnet 4.6/4.5 — each only months old but not yet retired, since API customers often stay a generation behind to avoid re-testing production workflows.
How does Claude work?
Claude models are trained with Constitutional AI: instead of shaping behavior purely through human feedback, Anthropic has models critique and revise their own draft responses against a written set of principles, then reinforces that behavior during training. Alongside sits the Responsible Scaling Policy and AI Safety Levels (ASL) — Opus 4 was the first Claude deployed under the stricter ASL-3 standard, and Fable 5’s extra biology/cybersecurity safeguards are the clearest recent example.
Modern Claude combines the model with tools and adaptive reasoning:
- 1
Understand the request
Claude reads your prompt, conversation so far, uploads, connectors, and Memory.
- 2
Reason through the problem
Extended thinking (since 3.7 Sonnet Feb 2025) lets Claude work step by step before answering. An effort setting (low/medium/high) now controls reasoning compute per request.
- 3
Decide which tools to use
Web search, code execution, file generation, Computer Use screenshots, or MCP connectors (open standard Anthropic released Nov 2024).
- 4
Generate the response or take the action
The answer, spreadsheet, pull request, or finished deliverable — sometimes after working independently for minutes or hours.
- 5
Refine with follow-ups
Artifacts and Projects keep documents and code open and editable across the thread instead of restarting from scratch.
What can you do with Claude?
The agentic shift: Claude Code, Cowork, and Claude Tag
Anthropic’s biggest change since 2023 isn’t a smarter chatbot — it’s that Claude increasingly does the work instead of only describing how to do it. Three products carry that shift, each for a different way of working.
Claude in Chrome and the Excel/PowerPoint add-ins extend the same idea into browser and Microsoft apps, while Claude Design (research preview April 2026) applies it to slides and prototypes.
Claude timeline: 2021–2026
Dario and Daniela Amodei found Anthropic as a Public Benefit Corporation with five other ex-OpenAI colleagues, around Constitutional AI.
Claude 1 and Claude Instant launch via Anthropic API — first public release. 100K-token window arrives that May, ahead of any frontier lab.
Claude 2 ships; 2.1 doubles context to 200K in November.
Claude 3 introduces Haiku/Sonnet/Opus structure with vision in all three tiers, carried through every generation since.
Claude 3.5 Sonnet launches alongside Artifacts, the live editing pane.
Updated 3.5 Sonnet and 3.5 Haiku ship with Computer Use in public beta.
Anthropic open-sources Model Context Protocol (MCP), the standard for connecting assistants to external tools.
Claude 3.7 Sonnet introduces hybrid extended-thinking reasoning; Claude Code launches as research preview the same day.
Claude Opus 4 and Sonnet 4 reach GA alongside Claude Code’s own GA — Opus 4 first Claude under ASL-3.
Sonnet 4.5 adds context-awareness; Haiku 4.5 follows in October as first Haiku with extended thinking and computer use.
Opus 4.5 ships alongside Chrome and Excel integrations.
Cowork rolls out from Max to every paid plan; Opus 4.6 and Sonnet 4.6 follow, with 1M context window in beta.
Opus 4.8 launches.
Fable 5 and Mythos 5 launch as first Mythos-class models (June 9); export-control suspension June 12–30; Tag launches in Slack June 23; Sonnet 5 launches June 30.
Access to Fable 5 restored July 1; Opus 5 launches July 24 — fourth model release in under two months.
How to use Claude well
The prompt pattern that works
Role, task, format — the same structure every assistant in this series responds well to. For long-running work, put background material in a Project once instead of re-pasting it into every chat.
How large is the context window?
Claude Fable 5, Mythos 5, Opus 5, and Sonnet 5 all carry a standard 1 million-token context window — roughly 750,000 words — with up to 128,000 tokens of output. Haiku 4.5 stays at 200,000 tokens, about 150,000 words, with a 64,000-token output ceiling.
Practical rule of thumb: a token is roughly 0.75 English words, and about 1.5 tokens per word once you factor in punctuation and spacing. Claude was the first frontier-lab model to reach a 100,000-token window in May 2023.
What does Claude cost?
| Plan | Price | Model access | Limits |
|---|---|---|---|
| Free | $0 | Sonnet 5 | Capped daily messages; no Code or Cowork |
| Pro | $20/mo ($17/mo annual) | Sonnet 5 default, Opus 5 available | 5x Free’s usage; first plan to include Cowork |
| Max 5x | $100/mo | Opus 5 default | 5x Pro’s usage per session, for sustained Code/Cowork |
| Max 20x | $200/mo | Opus 5 default | 20x Pro’s usage, for parallel sessions and heavy agents |
| Team Standard | $20/seat/mo annual ($25 monthly) | Sonnet 5, Opus 5 | 2–150 seats; shared billing and admin |
| Team Premium | $100/seat/mo annual ($125 monthly) | Adds Code, Cowork, Fable 5 in limits | Same 2–150 seats |
| Enterprise | $20/seat/mo + usage at API rates | Full lineup | SSO, SCIM, HIPAA-eligible; 20+ seats self-serve, 50+ sales-assisted |
| API | usage-based | Fable 5 $10/$50 · Opus 5 $5/$25 · Sonnet 5 $2/$10 · Haiku 4.5 $1/$5 per 1M | Prompt caching -90%, Message Batches -50% |
Sonnet 5 $2/$10 intro made permanent Aug 10, 2026. Prices and limits change often; the chart above reflects August 2026.
Frequently asked questions
Heads-up:Claude is a fast-moving product, and Anthropic has shipped four model generations and three agentic surfaces in the past 18 months alone. Plan names, model names, and prices change frequently — the details above reflect August 2026. Check Anthropic’s official pricing and docs for current limits.