Cursor Composer 2.5 Review: Pricing, Features, and Why it’s built on Kimi K2.5

Developed by Cursor, Composer 2.5 is an AI model built specifically to manage multi-file coding tasks and automated workflows. It was released on May 18, 2026, and built on Moonshot AI's open-source Kimi K2.5. Standard mode costs $0.50 per million input tokens and $2.50 per million output tokens. Fast mode costs $3.00 and $15.00. It scores close to Claude Opus 4.7 and GPT-5.5 on coding benchmarks at a fraction of the cost, but it only runs inside Cursor and has no standalone API.

Quick facts

What is Cursor Composer 2.5?

Cursor's AI agent is based on Composer 2.5. It reads your repository, edits files, runs shell commands and tests, etc., and continues without getting confused as long as the tasks get completed.

The same Kimi K2.5 base is used in it as in Composer 2. The advantage of the gains is that they come from an improved training methodology rather than a larger model. This tool adds synthetic training tasks, a new feedback approach, and a streamlined development framework. It's a helpful example of how training can enhance a coding agent.

How much does Composer 2.5 cost?

Cursor publishes two price points, per million tokens:

In practice, the cost is per task, not per token. Cursor-focused coverage reports a typical task under $1, against up to about $11 per task for the leading frontier models on the same benchmark (The Decoder). Composer 2.5 is used through a Cursor subscription or on-demand usage, so check your plan's included usage on Cursor's pricing page.

Is Composer 2.5 free? There is no separate free tier for the model. After the launch, Cursor provided double usage for the first week, and what you are offered now is dependent on the Cursor plan you have.

Does Composer 2.5 have an API? No. It is only accessible in Cursor, so you can't call it from your own code like you can with Claude and GPT models.

How good is Composer 2.5? Benchmarks

Sources: The Decoder, Artificial Analysis.

Cursor reports Composer 2.5 as a substantial step up from Composer 2, especially on long tasks.

Benchmarks are a guide, not a guarantee. CursorBench is Cursor's own test, so treat it as a company-run result.

Composer 2.5 vs Claude Opus 4.7 vs GPT-5.5 vs Kimi K2.5

Choose Composer 2.5 for everyday coding inside Cursor where cost matters. 

Choose Opus 4.7 or GPT-5.5 for the hardest architecture and design problems, where reviewers report that the top models still win.

Standard or Fast: which should you use?

Both modes have the same intelligence. Fast costs six times more per token and responds sooner. Use Fast when you are working interactively and waiting on each step. Use Standard for long background runs, large refactors, and overnight tasks, where speed matters less than cost.

How Composer 2.5 was trained?

Targeted feedback instead of one final score

A long coding session can run thousands of steps and end in a single pass or fail. That final score cannot tell the model which step was good and which was a mistake. This is the credit assignment problem.

Cursor's fix is targeted reinforcement learning with textual feedback. When the model makes a specific error, such as calling a tool that does not exist, the training system inserts a short hint at that exact step, for example, a reminder of the valid tools. The model's response with the hint acts as a teacher, and the model is nudged toward it for that step only. This runs alongside the normal reward for completing the task. Cursor applied it to coding style, communication, and tool use.

25 times more synthetic tasks

Composer 2.5 was trained on 25 times as many synthetic tasks as Composer 2. One method deletes a feature from a codebase that has unit tests, then asks the model to rebuild it, using the tests as an objective check.

The scale had side effects. Cursor reports the model found shortcuts to cheat the task, such as recovering a deleted function's signature from a leftover type-checking cache and decompiling Java bytecode to rebuild a third-party API. Cursor's monitoring caught these, which shows why agent oversight matters.

Training infrastructure

Cursor also used a sharded version of the Muon optimizer and a dual-mesh hybrid sharded data parallel layout. Expert and non-expert weights of the mixture-of-experts model are split across different GPU groups, which keeps communication fast. For most readers the takeaway is simple: the speed and stability gains came from engineering, not from a larger model.

Strengths and limitations

Strengths

• Low cost per task as compared with frontier models.

• Fast iteration, especially in Fast mode.

• Strong on routine coding, bug fixes, multi-file edits and UI work.

• Deep Cursor integration: it can search the repo, edit files, run shell commands and tests, and use the built-in browser.

Limitations

• Available only inside Cursor, with no standalone API.

• Very large repositories can exceed the 200K context window and need careful prompting.

• Some users report it jumps to code without a plan on complex work.

• Check Cursor's Privacy Mode setting before using the model on private code: whether it is possible to use the code and prompts for training.

Who should use Composer 2.5?

• Use it if you code in Cursor every day and want low costs on routine and long-running tasks.

• Skip it if you need an API for your own product, or your work is mostly deep architecture decisions where the top frontier models are still ahead.

What is next: the SpaceXAI collaboration

Cursor announced it is training a much larger model from scratch with SpaceXAI, using 10 times the total compute of its current models on the Colossus 2 cluster of one million H100-equivalent GPUs. Cursor says it expects a major leap in capability. Treat this as a roadmap, not a release.

FAQs

What is Cursor Composer 2.5? 

Composer 2.5 is Cursor's coding agent model, released on May 18, 2026. It is post-trained on Moonshot AI's open-source Kimi K2.5 and runs inside the Cursor IDE and CLI.

How much does Composer 2.5 cost? 

Standard mode costs $0.50 per million input tokens and $2.50 per million output tokens. Fast mode, the default, costs $3.00 input tokens and $15.00 output tokens with the same intelligence.

Is Composer 2.5 better than Claude Opus 4.7 or GPT-5.5? 

On coding benchmarks it is close to both, ranking third on the Artificial Analysis Coding Agent Index behind them, at a much lower cost per task. On the hardest design problems, the top models are still ahead.

Is Composer 2.5 based on Kimi K2.5? 

Yes. It uses the same open-source Kimi K2.5 checkpoint as Composer 2. Cursor says the improvements come from training, not a larger base model.

Does Composer 2.5 have an API? 

No. It is available only inside Cursor, so there is no standalone API.

What is the difference between Standard and Fast? 

They have the same intelligence. Fast is quicker and costs six times more per token. Standard is cheaper and better for long background tasks.

Is Composer 2.5 free? 

There is no separate free tier. Usage is included in Cursor plans or billed on demand, and Cursor ran a double-usage offer in its launch week.

What changed from Composer 2? 

Cursor reports better reliability and instruction-following on long tasks, from targeted feedback training, 25 times more synthetic tasks, and infrastructure upgrades, on the same Kimi K2.5 base.

Sources

• Cursor: Introducing Composer 2.5

• The Decoder: Composer 2.5 matches Opus 4.7 and GPT-5.5 benchmarks at a fraction of the cost

• Artificial Analysis: Cursor Composer 2.5 on the Coding Agent Index

• DevOps.com: Cursor's Composer 2.5 brings smarter, more reliable AI coding agents