Announcement
New Models

Claude Opus 5

July 29, 2026
Thesean

The same product, a new grade: ship-like/claude-opus-5 matches Claude Opus 5's quality and behavior at at least half the cost (guaranteed), backed by our quality SLA.

CONTENTS

Ship gives you the highest intelligence per dollar of any frontier model by finding the cheapest execution that still meets a model's quality grade. We first introduced it for Claude Opus 4.8 and GPT 5.6 Sol. Today we're adding Claude Opus 5 with the same quality SLA, the same cost reduction, and the same ease of use.

Same Performance - Half the Cost

Just name a reference model as a quality grade, and we fulfill each request in the cheapest way that still meets that grade. We measure both Capability Equivalence and Behavioral Equivalence to the reference model, so that the model performs as well as expected, and it works the same way within your harness when you switch to ship.

TL;DR. Change model="claude-opus-5" to model="ship-like/claude-opus-5". Same answers, same behavior, for at least 50% less (in our evals, closer to 46%) with a quality SLA.

New to Ship? Start with Introducing Ship.

Capability equivalence

Across every public benchmark we tested, Ship lands inside its reference model's margin of error — at a fraction of the cost per task.

Behavioral equivalence

A drop-in replacement has to act like the model it replaces, or you'd have to change your harness (prompts, parsers, tools, etc.). Claude Opus 5's Ship grade has a high distributional overlap with it across nine behavioral axes.

Behavioral fingerprint

normalized axes · Ship dashed against the selected base

Zoom into tool use and the two grades reach for the same tools in the same proportions — so a prompt tuned to Claude Opus 5's tool habits behaves the same on Ship.

The time budget splits the same way, too — most of it in model generation, the rest in tool execution — so latency profiles match, not just totals.

Tool-call mix (average)

Where the time goes (average)

model generation vs tool execution

Step back to the whole trace and the equivalence is holistic: embed each run and Ship lands inside Claude Opus 5's cloud, while a model with similar benchmark performance sits clearly apart.

Ship traces sit inside the base cloud

task-centered embeddings · t-SNE

And it's task-for-task, not just on average. Bucket every task by how often Claude Opus 5 solves it, and Ship tracks it bucket-for-bucket far more tightly than any other model — the same hard tasks stay hard, the same easy ones stay easy.

Other models within each Claude Opus 5 solve-rate bucket

tasks sorted by base solve rate · color = solve rate

Get started

This new ship model is available now. Swap one string:

model="ship-like/claude-opus-5"

Bring your private evals or production traffic and we'll compare Ship against your current model directly.

Thesean