Claude Haiku 4.5 — Fast Lightweight AI Model on Craze

About Claude Haiku 4.5

Claude Haiku 4.5 is the fastest and lightest model in the Claude family — built for tasks where latency and cost matter more than peak intelligence. Quick replies in chat, routine classification, summarisation, agent steps that just need a tidy answer fast.

Despite being the small Claude, Haiku 4.5 still supports tool calling, vision, streaming, and MCP, so it slots into the same Craze workflows as Opus and Sonnet — you just trade a little reasoning depth for a lot more throughput.

Use Haiku in agents that fan out across many parallel steps, in interfaces where a person is waiting for a reply, or as the executor that follows a plan laid down by a heavier model. Cheap enough to use everywhere, sharp enough that you won't usually notice the difference on routine work.

What Claude Haiku 4.5 is good at

Sub-second latency on routine work

Returns first tokens in a fraction of a second. The Claude to reach for when a person — or an interface — is waiting for a reply.

High-volume classification

Strong on tag-this, route-that, summarise-this work. Useful behind triage agents and any pipeline that processes many small inputs.

Fast summarisation

Compresses long inputs — emails, transcripts, docs — into clean briefs without losing the load-bearing details.

Tool use, MCP, and structured output

Same agentic surface as the bigger Claudes — tool calls, MCP servers, strict JSON — at a fraction of the per-step cost. Great for the executor leg of a planner/executor agent.

Vision on the cheap

Reads screenshots and basic documents. Useful for OCR-like extraction and quick image triage where you want speed over depth.

Use Claude Haiku 4.5 on Craze

On Craze, Claude Haiku 4.5 shows up wherever you'd reach for an AI model — the chat composer, the model picker, every connected workflow. Pick it once and your conversation, drafts, and agents follow you across the rest of the workspace.

Build AI agents on top of Claude Haiku 4.5 that hand off context to teammates, pull from the apps you've already connected, and keep working in the background while you focus on something else.

Or hand Claude Haiku 4.5 a routine task and switch to another model when the next step needs different strengths — you can mix and match models in the same conversation without losing context.

When to choose Claude Haiku 4.5

Choose Haiku 4.5 when speed and cost matter more than peak reasoning — quick chat, classification, summarisation, the executor leg of an agent that's been planned by a heavier model. Step up to Sonnet 4.6 for meatier work, or to Opus 4.7 / GPT 5.5 when an answer has to be especially careful.

Common questions about Claude Haiku 4.5

What is Claude Haiku 4.5?

Claude Haiku 4.5 is Anthropic's lightweight Claude model. It's tuned for low-latency chat, classification, summarisation, and high-volume agent steps — tasks where snappy responses matter more than the absolute deepest reasoning.
How fast is Claude Haiku 4.5 compared to Opus or Sonnet?

Haiku is significantly faster than both Opus and Sonnet, typically returning first tokens in a fraction of a second. The trade-off is a small dip in reasoning depth on the hardest tasks — for most everyday work you won’t notice.
How much does Claude Haiku 4.5 cost on Craze?

Haiku 4.5 is included in every paid Craze plan — no per-token billing on your side. One Craze membership covers Haiku alongside Sonnet, Opus, GPT 5.5, and everything else.
When should I use Haiku 4.5 instead of Sonnet 4.6?

Reach for Haiku when you want responses fast and cheap — quick chat replies, classification, summarisation, agent steps that just need a clean answer at high volume. Use Sonnet 4.6 when the task is meatier and you'd accept a small latency hit for stronger reasoning.
Does Claude Haiku 4.5 support tools and agents?

Yes — Haiku 4.5 supports tool calling, MCP servers, vision, and structured outputs. Inside Craze it plugs into every connector you've added so agents can read context and take action at low cost.
Do I need an Anthropic API key for Haiku 4.5?

No. Craze takes care of authentication and billing. Sign up and Haiku 4.5 is available right away from the model picker in chat, agents, and anywhere else a model gets used.

Documentation & links

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Last updated: May 15, 2026