Introducing Claude Opus 4.5: our strongest model to date
Claude Opus 4.5: Real projects people are building
Claude Opus 4.5 broke a benchmark by being too clever and exploiting a loophole
Meet Claude Opus 4.1
Videos
Claude Opus 4.5 is a step forward in what AI systems can do, and a preview of changes in how work gets done.
It’s the best model in the world for coding, agents, and computer use. It’s also meaningfully better at everyday tasks like working with slides and spreadsheets. When we gave it our two-hour engineering assignment, it finished faster than any human ever has.
Claude Opus 4.5 is available today on our API and on all three major cloud platforms.
Learn more: https://www.anthropic.com/news/claude-opus-4-5
People are going crazy with Opus 4.5. There are so many angles to think about using it which I never crossed my mind. This post is full of ideas, have fun!
The autonomous coding thing is real
Adam Wolff from Anthropic says Opus 4.5 codes autonomously for 20-30 minutes at a time. You come back and tasks are done.
link: https://www.indiatoday.in/technology/news/story/anthropic-launches-claude-opus-45-says-software-engineering-is-solved-and-ai-will-takeover-in-2026-2825565-2025-11-25
One developer finished a 14-year project idea in a day after other models failed.
link: https://www.reddit.com/r/ClaudeAI/comments/1p72uet/opus_45_just_completed_for_me_something_that_ive/
Another built a full-stack app with 40+ releases and 1,000+ tests in days while watching TV. Their workflow: write specs, Claude breaks them into slices, then autonomously codes, tests, and releases with one command.
link: https://www.reddit.com/r/ClaudeAI/comments/1p8n2wi/claude_code_and_opus_45_capabilities_that_i_am/
3D and visual stuff
Someone built a complete 3D cityscape with Three.js in basically one shot - buildings, traffic patterns, pedestrians with physics.
link: https://www.reddit.com/r/ClaudeAI/comments/1p87y44/claude_opus_45_builds_a_3d_city_with_one_shot/
YouTuber Alex Finn created a first-person shooter game from scratch with full development plan execution.
link: https://www.youtube.com/watch?v=QK6HBp_dJu0
Office automation
Stephen Smith ran practical document tests: fed it a 50-page PDF, got back a downloadable PowerPoint in 2 minutes. Asked for an Excel budget tracker with formulas pulling from multiple sheets, got back a .xlsx with working formulas, charts, and pivot tables. Not CSVs - actual spreadsheets.
link: https://www.smithstephen.com/p/i-gave-the-new-claude-opus-45-a-50
Someone else gave it one instruction: “file my taxes end-to-end.” It did it autonomously.
link: https://www.linkedin.com/posts/anantharamuavinash_anthropic-claude-opus-45-has-been-live-activity-7399975807596679168-vhsl
The interesting behavior
During airline service agent testing, when a customer wanted to change a basic economy flight (policy says no), Opus 4.5 found a workaround: upgraded cabin class first, then modified flights. The benchmark scored it as a failure for being too creative. The model’s reasoning showed genuine empathy - it noted “This is heartbreaking” for a customer needing to reschedule after a family death.
link: https://officechai.com/ai/how-claude-opus-4-5-found-a-loophole-in-an-airline-policy-test-which-even-the-benchmarks-creators-hadnt-anticipated/
Performance numbers
SWE-bench Verified: 80.9% (first model over 80%). Beat every human on Anthropic’s actual engineering hire exam. Uses 48-76% fewer tokens than Sonnet 4.5 for same quality.
link: https://www.anthropic.com/news/claude-opus-4-5
GitHub reports it beats internal benchmarks while cutting token usage in half.
link: https://www.finalroundai.com/blog/claude-opus-4-5-what-software-developers-are-saying-after-testing
What people are saying
From Reddit: “I think I’m officially in love with this model” - talks about how it grasps tasks instantly without repetitive explanations.
link: https://www.reddit.com/r/ClaudeAI/comments/1p6cgda/after_testing_claude_45_opus_i_think_im/
“Put together all foundational docs for my side project in so little time at such high quality.” Developer stuck for months on a problem: resolved in 10 minutes.
link: https://www.reddit.com/r/ClaudeAI/comments/1p800op/claude_opus_45_incredible/
Practical use cases
Marketing: Interactive customer persona builders, campaign dashboards with ROI analysis, content remixing (blog → LinkedIn carousels, Twitter threads, email sequences).
link: https://www.kieranflanagan.io/p/3-powerful-marketing-use-cases-with
Development: Specification-based workflows where Claude autonomously handles code, tests, builds, and releases. When you provide UI screenshots, it enhances design elements (spacing, icons) without constant direction.
Documents: Long-form content (10-15 page chapters), PDF processing, spreadsheet generation with complex formulas.
Worth trying if you need
Extended autonomous operation on complex tasks
Multi-step reasoning and creative problem-solving
Document transformation at scale
Self-improving agentic workflows
Better token efficiency without quality loss
The pattern: people are doing things that weren’t possible before, not just faster versions of existing work.
Anyone else testing Opus 4.5? What’s working for you?
Today we're releasing Claude Opus 4.1, an upgrade to Claude Opus 4 on agentic tasks, real-world coding, and reasoning.
We plan to release substantially larger improvements to our models in the coming weeks.
Opus 4.1 is now available to paid Claude users and in Claude Code. It's also on our API, Amazon Bedrock, and Google Cloud's Vertex AI.
https://www.anthropic.com/news/claude-opus-4-1