Here's what it feels like to use Opus 4.5 every day, written the way I'd tell a friend over coffee.
The launch timing was weird: Gemini 3 Pro stole the mic for a day, then everyone vanished for turkey. So the best coding model and the best agent model slipped in the side door while the Internet was sleeping. People just haven't caught up yet.
The hype around "2025 is the year of agents" finally makes sense.
Remember how GPT-4 turned "chat with a computer" into something you'd actually do? Then Sonnet 3.5 did the same for "hey, can you write this code?" Opus 4.5 is that jump again, but for "go handle this whole codebase and ping me when it's done." The first time you watch it plan, iterate, fix its own bugs, and finish a two-hour job while you play Expedition 33, the room tilts a little. After that, the old way feels like the sounds of a dial-up modem.
The Iron Man suit analogy is cheesy but weirdly accurate. Half the time it moves before I finish the sentence: creates a branch, opens the right files, dumps in tests I hadn't even asked for yet. You stop thinking "prompt" and start thinking "delegate."
Then there's the Claude Agent SDK, the quiet half of the duo. A model is only as stubborn as the harness holding it. Anthropic built both pieces, so the thing doesn't wander off and halucinate a vacation to Fiji. Glue them together and you get agents that actually finish the job instead of ghosting you after step three. If you're serious about shipping, that pairing is the cheapest super-power on the market right now.
I've caught myself laughing at the screen more than once (pure reflex, the way you laugh when a friend pulls off a stunt you didn't see coming). Ilya Sutskever's line keeps looping in my head: "You know what's crazy? That all of this is real." Yup, still crazy.
Bottom line, Opus 4.5 is the first model I'd trust to babysit a repo overnight. If you've been waiting for the "year of agents" to feel real, open the SDK, pick a task you hate, and go grab dinner. When you come back, the task will be done, and you'll never want to do it yourself again.