What is Claude Academy?

Claude Academy is the #1 free interactive learning platform by Infinity Tech Stack designed to help developers master Anthropic's Claude AI ecosystem, including Claude Series 5 (Fable 5.1, Opus 5.5, Sonnet 5.5, Haiku 5.5), Claude Code CLI, Claude Agent SDK, and the Model Context Protocol (MCP) through 18 modules, 31 lessons, 31 terminal labs, and 81 quizzes with zero sign-up required.

How is Infinity Claude Academy different from official Anthropic Claude Academy?

While Anthropic's official portal (academy.claude.com) provides broad conceptual AI fluency, Infinity Tech Stack's Claude Academy is an independent, 100% free developer-focused systems curriculum requiring no sign-up. It features 18 deep technical modules, 31 lessons, 31 in-browser terminal sandbox labs, 81 quizzes, and comprehensive training on Claude Code CLI, Model Context Protocol (MCP) server creation, prompt caching, and multi-agent workflows.

How long does Claude Academy take to complete?

Claude Academy contains approximately 3 to 5 hours of interactive material across 18 modules and 31 lessons. Because all progress is saved locally in your browser, you can complete the curriculum at your own pace.

Is the Claude Academy free?

Yes, 100% free. No sign-up, no credit card. All 18 modules, 31 lessons, 81 quizzes, and 31 interactive browser terminal labs are immediately accessible. Progress saves locally in your browser.

What topics does the Claude Academy cover?

The course covers Claude AI fundamentals, prompt engineering, CLAUDE.md, Claude Code CLI, Claude Agent SDK, the Messages API, tool use & function calling, MCP integration, streaming, prompt caching, agentic workflows, multi-agent systems, computer use, vision API, adaptive thinking, and Claude Series 5 (Fable 5.1, Opus 5.5, Sonnet 5.5, Haiku 5.5).

Is Claude AI better than ChatGPT?

Claude excels at coding, long-context reasoning, and instruction following. ChatGPT has a wider plugin ecosystem. This course teaches you to maximize Claude's unique strengths including adaptive thinking, 1M token context windows, and native tool use.

CLAUDE.md is a project-level configuration file that gives Claude Code persistent context about your codebase - conventions, architectural patterns, and preferences that persist across sessions.

What is the Opus 4.8 tokenizer and how does Claude count tokens?

Introduced in Claude Opus 4.7/4.8 and carried into Claude 5.x (Opus 5.5, Sonnet 5.5, Haiku 5.5, Fable 5.1), Anthropic's updated BPE tokenizer uses finer-grained token boundaries for code and technical syntax, mapping identical text to roughly 1.0x-1.35x tokens (~555,000 words per 1M context window vs ~750,000 words on legacy tokenizers). Because legacy character heuristics underestimate counts, developers learn to measure exact pre-flight usage with the free /v1/messages/count_tokens API and apply Prompt Caching for 90% to 97.5% cache read discounts.

Do I need programming experience?

No prerequisites required. The course starts from absolute basics (what is Claude?) and progressively advances to expert topics like agentic workflows and multi-agent orchestration.

Do I need to sign up or create an account to use Claude Academy?

No sign-up or login is required. Unlike official enterprise portals, Infinity Tech Stack's Claude Academy is 100% free and open. You can immediately access all 18 modules, 31 lessons, and 31 interactive browser terminal labs without entering an email or password. Progress is saved locally in your browser.

Does the Claude Academy include hands-on labs?

Yes. All 31 lessons include hands-on labs - a simulated terminal in your browser where you type real, vendor-verified commands: curl the Messages API, count tokens with count_tokens, and run Claude Code headless. Labs include objectives, hints, solutions, and XP rewards. No sign-up or setup needed.

What is the standard context window across all four current Claude 5.x GA models (Fable 5.1, Opus 5.5, Sonnet 5.5, Haiku 5.5)?

1M tokens (1,000,000) — All four current Claude 5.x models—including Haiku 5.5—feature a unified 1M token context window and 128K max output.

What is the standard input and output token pricing for Claude Opus 5.5 and Claude Sonnet 5.5 per million tokens?

Opus 5.5: $4.00/$20.00, Sonnet 5.5: $2.00/$10.00 — Claude Opus 5.5 is priced at $4.00 input / $20.00 output per MTok, and Claude Sonnet 5.5 is priced at $2.00 input / $10.00 output per MTok.

How is Claude Haiku 5.5 (claude-haiku-5-5) priced for high-throughput routing and classification?

$0.10 input / $0.50 output per MTok for prompts 100K) — Claude Haiku 5.5 delivers 1M context capacity with tiered pricing: $0.10 / $0.50 per MTok up to 100K prompt tokens, and $0.50 / $2.50 per MTok above 100K tokens.

What is the operational status of legacy models (Claude 2.x, Claude Instant 1.2, Claude 3.5 Sonnet, Claude 3 Opus, Claude 3.7 Sonnet, Claude 4.0/4.1) and /v1/complete?

They are officially retired/shut down, requiring migration to active Claude 5.x models (Fable 5.1, Opus 5.5, Sonnet 5.5, Haiku 5.5) via /v1/messages — Anthropic has retired Claude 2.x, Instant 1.2, 3.5 Sonnet (Oct 2025), 3 Opus (Jan 2026), 3.7 Sonnet (Feb 2026), and Claude 4.0/4.1 (Summer 2026), along with /v1/complete. Production apps must target active 5.x models on /v1/messages.

The Official Claude Model Lineup — Models & Architecture

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The Official Claude Model Lineup

🏛️ Models & Architecture⏱ 15 min⭐ 100 BASE XP⌨ HANDS-ON LAB

Official Claude Models Overview (October 2026)

Anthropic's current Series 5.x model family standardizes 1M token context windows, 128K max output tokens, and a June 2026 knowledge cutoff across all four active GA tiers:

Model	Model ID	Context Window	Max Output	Pricing (In / Out per MTok)	Lifecycle Status	Primary Use Case
Claude Fable 5.1	`claude-fable-5-1`	1M tokens	128K tokens	$10.00 / $50.00	● ACTIVE (Top Reasoning)	Demanding reasoning, complex problem solving, long-horizon agentic work (always-on adaptive thinking, default effort: high)
Claude Opus 5.5	`claude-opus-5-5`	1M tokens	128K tokens	$4.00 / $20.00	● ACTIVE (Upper Tier)	Long-running agentic coding, deep systems architecture, heavy knowledge work (always-on adaptive thinking, default effort: medium)
Claude Sonnet 5.5	`claude-sonnet-5-5`	1M tokens	128K tokens	$2.00 / $10.00	● ACTIVE (Recommended)	Best combination of speed, cost, and intelligence for everyday coding and multi-tool workflows (default effort: high)
Claude Haiku 5.5	`claude-haiku-5-5`	1M tokens	128K tokens	$0.10 / $0.50 (≤100K) $0.50 / $2.50 (>100K)	● ACTIVE (Entry Tier)	High-volume, latency-sensitive classification, routing, and rapid extraction (default effort: medium)
Claude Mythos 5	`claude-mythos-5`	1M+ tokens	128K tokens	Gated Program	◆ RESTRICTED PREVIEW	Gated cyber/life-sciences research tier; public GA workloads deploy on Claude Fable 5.1
Claude Opus 5 / Sonnet 5	`claude-opus-5` / `claude-sonnet-5`	1M tokens	128K tokens	$5 / $25 • $2 / $10	● ACTIVE (5.0 Baseline)	Earlier Series 5 releases; upgrade to Opus 5.5 ($4/$20) and Sonnet 5.5 ($2/$10)
Claude Haiku 4.5	`claude-haiku-4-5-20251001`	200K tokens	64K tokens	$1.00 / $5.00	▲ LEGACY (Superseded)	Removed from consumer UI Oct 29, 2026; migrate to Claude Haiku 5.5 (10x cheaper at ≤100K, 5x larger context)
Claude 4 / 4.1 / Sonnet 4.5	`claude-sonnet-4` / `claude-opus-4`	200K tokens	64K tokens	$3/$15 • $15/$75	■ RETIRED / DEPRECATED	Claude 4.0 retired June 15, 2026; Opus 4.1 retired Aug 5, 2026; Sonnet 4.5 deprecated Sept 30, 2026 (EOL Nov 30, 2026)
Claude 3.7 Sonnet	`claude-3-7-sonnet-20250219`	200K tokens	128K (beta) / 8K	$3.00 / $15.00	■ RETIRED (EOL Feb 19, 2026)	Retired hybrid reasoning pioneer; migrate to Claude Sonnet 5.5
Claude 3.5 Sonnet	`claude-3-5-sonnet-20241022`	200K tokens	8,192 tokens	$3.00 / $15.00	■ RETIRED (EOL Oct 28, 2025)	Retired predecessor; migrate to Claude Sonnet 5.5
Claude 3 Opus	`claude-3-opus-20240229`	200K tokens	4,096 tokens	$15.00 / $75.00	■ RETIRED (EOL Jan 5, 2026)	Retired predecessor; migrate to Claude Opus 5.5 or Claude Fable 5.1
Claude 2.0 / 2.1	`claude-2.0 / claude-2.1`	100K - 200K tokens	4,096 tokens	$8.00 / $24.00	■ RETIRED / SHUT DOWN	Officially retired; migrate to active Claude 5.x models via Messages API
Claude Instant 1.2	`claude-instant-1.2`	100K tokens	4,096 tokens	$0.80 / $2.40	■ RETIRED / SHUT DOWN	Officially retired; migrate to Claude Haiku 5.5
Text Completions (/v1/complete)	Legacy API endpoint	N/A	N/A	N/A	■ SHUT DOWN	Retired legacy endpoint; all workloads must route to /v1/messages

The Series 5.5 Architectural Leap

Anthropic's Claude 5.5 & Fable 5.1 lineup standardizes 1M token context windows, 128K max output tokens, and a June 2026 knowledge cutoff across every tier—including Haiku 5.5. Rather than requiring manual budget_tokens allocation, all current models support Adaptive Thinking steered via output_config.effort.

⌨ HANDS-ON LABQuery the Live Models Catalog

⭐ +100 XP

Verify which Claude models are active on your account. Query the official /v1/models endpoint via REST.

1Send a GET request to https://api.anthropic.com/v1/models with your API key.

lab-sandbox — simulated environment

INFINITY LAB SANDBOX v2.6 — simulated shell
Type the command for the current objective. Helpers: "hint", "solution", "clear".
$

OBJECTIVE 1 / 1 — type "hint" if stuck

SYNAPSE VERIFICATION

QUERY 1 // 5

Which model is Anthropic's top-tier GA model for demanding reasoning and long-horizon agentic workflows?

Claude Haiku 4.5

Claude Fable 5.1 (claude-fable-5-1)

Claude 3.5 Haiku

Claude Instant