Claude
Claude is Anthropic's family of large language models — built for conversation, reasoning, coding, and increasingly, taking action through tools and agents. This page covers what Claude actually is, the current model lineup, how it shows up across different products, and a detailed roadmap for going from a first conversation to building production agent systems.
What is Claude?
Claude is a large language model: a system trained on enormous amounts of text that learns to predict and generate language, which turns out to be enough to hold a conversation, write and debug code, analyze documents, and reason through multi-step problems. Anthropic, the company behind it, designs Claude with safety as a core constraint rather than an afterthought — Claude is trained to decline harmful requests and to be transparent about what it doesn't know.
A few properties matter once you start using Claude for real work. Its context window — how much conversation and document text it can consider at once — now reaches up to a million tokens on the largest models, enough to hold an entire codebase or a long document collection in a single request. Extended thinking lets Claude reason step by step before answering on problems that need it. And tool use turns Claude from something that only answers questions into something that can search the web, run code, edit files, and call your own application's functions.
The Claude model family
Anthropic ships a few model sizes at any given time, each trading off intelligence, speed, and cost differently. Model names, limits, and pricing change as new versions ship — this is a snapshot, not a permanent reference.
Claude Opus 4.8
Flagshipclaude-opus-4-8The most capable Opus-tier model: state-of-the-art on long-horizon agentic work, knowledge work, and memory. The right default when intelligence matters more than cost.
- Context
- 1M tokens
- Max output
- 128K tokens
- In / out price
- $5 / $25 per MTok
Claude Sonnet 4.6
Balancedclaude-sonnet-4-6The best combination of speed and intelligence for everyday use and production apps — most integrations should start here.
- Context
- 1M tokens
- Max output
- 64K tokens
- In / out price
- $3 / $15 per MTok
Claude Haiku 4.5
Fastclaude-haiku-4-5The fastest, most cost-effective model. Built for high-volume, latency-sensitive tasks like classification, extraction, and chat at scale.
- Context
- 200K tokens
- Max output
- 64K tokens
- In / out price
- $1 / $5 per MTok
Claude Fable 5
Most capableclaude-fable-5Anthropic's most capable widely released model, built for the hardest reasoning and the longest-horizon agentic work.
- Context
- 1M tokens
- Max output
- 128K tokens
- In / out price
- $10 / $50 per MTok
How people use Claude
Claude shows up in a few distinct surfaces, from simplest to most involved.
Claude.ai & apps
Chat with Claude in the browser, desktop, or mobile app — the easiest way to start, no setup required.
Claude API & SDKs
Call Claude programmatically from Python, TypeScript, Go, Java, Ruby, and more to build it into your own product.
Tool use & agents
Give Claude tools — search, code execution, or your own functions — so it can take actions, not just answer questions.
Claude Agent SDK & Managed Agents
Build autonomous, long-running agents. With Managed Agents, Anthropic runs the agent loop and hosts the sandbox where its tools execute.
MCP (Model Context Protocol)
An open standard for connecting Claude to external tools and data — GitHub, Slack, databases — without writing one-off integrations for each.
Roadmap: learning Claude from beginner to expert
Four stages, each building on the last. Work through them in order — there's little value in agent architecture before you understand what a single request does.
Start talking to Claude
Get comfortable using Claude as an assistant before writing a single line of code.
- Create an account at claude.ai and have a real conversation — ask it to explain something, draft something, or debug a small problem.
- Learn the basics of a good prompt: be specific about the task, give relevant context, and say what “done” looks like.
- Try the same question on a faster, cheaper model and a more capable one, and notice the difference in depth versus speed.
- Learn what a context window is — the amount of conversation and documents Claude can consider at once, measured in tokens, not characters.
- Upload a document or image — Claude can read PDFs directly and reason over screenshots or photos.
Build your first integration
Move from chatting with Claude to calling it from your own code.
- Create an API key in the Anthropic Console and install the official SDK for your language — Python or TypeScript are the easiest starting points.
- Make your first request to the Messages API: a model name, a max_tokens limit, and a messages array is all it takes.
- Learn the difference between a system prompt (how Claude should behave) and user messages (the actual conversation).
- Stream responses so your app shows output as it's generated, instead of waiting for the full reply.
- Install Claude Code and use it on a real project — it's the fastest way to see an agentic coding workflow firsthand.
- Learn the basics of prompt caching: reusing a stable prefix, like a system prompt, across requests cuts both cost and latency.
Give Claude tools
This is where Claude stops just answering and starts acting.
- Define a custom tool — a function with a name, description, and JSON schema — and let Claude decide when to call it.
- Build a basic agentic loop: call the API, execute any tool Claude requests, send the result back, and repeat until the task is done.
- Use Anthropic's server-side tools — web search, web fetch, and code execution — so Claude can look things up or run code without you hosting anything.
- Turn on extended thinking for genuinely hard problems, and learn to tune the effort level as a cost-versus-quality dial.
- Try structured outputs to force a response into a JSON schema you define — useful for extraction and classification.
- Use vision for screenshots, charts, or scanned documents instead of plain text.
Design real agent systems
Production agents need more than a single tool call — they need architecture.
- Decide between a hand-rolled agent loop (full control) and a managed option where Anthropic runs the loop and hosts the sandbox, based on how much infrastructure you want to own.
- Connect Claude to real systems with MCP servers instead of writing a one-off integration for every tool.
- Design for long-running sessions: compaction and context editing keep a conversation usable well beyond a single context window.
- Coordinate multiple agents — a coordinator that delegates to specialized sub-agents for review, testing, or research.
- Get deliberate about caching strategy: stable content first, volatile content last, and know exactly what invalidates a cache prefix.
- Choose a deployment path that fits your constraints — the first-party API, or a cloud-hosted option — since they run the same models with different infrastructure trade-offs.
- Read the migration notes whenever a new model ships — defaults and behavior shift between versions, and treating an upgrade as “just changing a string” causes regressions.
Things to keep in mind
Match the model to the task
Use a fast, cheap model for simple or high-volume work, and save the most capable model for genuinely hard reasoning.
Keep API keys server-side
Never ship an API key in client-side code — proxy requests through your own backend.
Treat tool inputs as untrusted
Validate and sandbox anything a tool executes — Claude's output is still just text until your code decides what to do with it.
Test before rolling out
Send one real request and inspect the response before wiring a model or prompt change into production.
ConsLabs is not affiliated with Anthropic. Model names, limits, and pricing on this page reflect a snapshot in time and will drift out of date — treat them as a starting point, not a live reference.