Cursor Composer 2.5 In-Depth Review: Is Vibe Coding at 200 Tokens/Second Actually Good?

Overview: Why Composer 2.5 Is Blowing Up in the Developer Community

Cursor released Composer 2.5 this Monday, and the buzz on X (Twitter) has far exceeded expectations. Looking at benchmark data, Composer 2.5 represents a quantum leap over its predecessor, placing it squarely in the same tier as Claude Opus 4.7.

In the SweepBench multilingual test, it ranks alongside Opus 4.7 and GPT 5.5. SWE-bench (Software Engineering Benchmark) is a standardized evaluation framework developed by a Princeton University research team in 2023, specifically designed to measure how well AI models solve real-world software engineering problems—it pulls tasks from actual GitHub Issues and requires models to autonomously fix code defects without solution hints. Its multilingual extension covers Python, JavaScript, TypeScript, Java, and other mainstream languages, making it much closer to real development scenarios.

Even more noteworthy are the results from Cursor's own Cursor Bench—Composer 2.5 outperforms both GPT 5.5 and Opus 4.7, while averaging just 55 cents per task, far below competitor costs. While some may question potential bias in an in-house benchmark, the independent Artificial Analysis (an independent AI performance evaluation firm whose Coding Agent Index scores models by executing end-to-end tasks in real codebases, widely regarded as a relatively objective third-party reference) coding agent index corroborates the findings: Composer 2 scored 48 in the Cursor Client, while Composer 2.5 achieved 63, described as "fast and strong, on par with GPT 5.5."

Speed Experience: How 200 Tokens/Second Changes Your Development Rhythm

Composer 2.5's most standout selling point is speed—token generation reaches 200 per second or higher.

Tokens are the basic units that large language models use to process text, roughly corresponding to 0.75 English words or about 1.5 Chinese characters. Tokens per second (TPS) is the core metric for measuring model inference speed and directly impacts user interaction experience. Mainstream commercial models like GPT-4o typically output in the 50-100 TPS range, while Composer 2.5 claims over 200 TPS—powered by the combined acceleration of Speculative Decoding, KV Cache optimization, and dedicated inference hardware (such as H100/H200 GPU clusters). High TPS is especially critical for code generation scenarios—developers' thought flow isn't interrupted by waiting, helping maintain a "flow state."

In actual testing, a simple TypeScript file modification (updating a YouTube subscriber count) took only 5-10 seconds from analysis to completion. This response speed makes rapid iteration truly possible and aligns perfectly with the Vibe Coding workflow paradigm.

Vibe Coding is a concept coined by OpenAI co-founder Andrej Karpathy in early 2025, describing a new programming paradigm driven by natural language intent where AI handles the actual implementation—developers no longer write code line by line but instead describe feature requirements, provide screenshots or examples, and let AI models handle code generation and iteration while they focus on direction and result verification.

However, speed is a double-edged sword. As the tester noted: "If I have 10 tasks running in the background with Opus 4.7, I have time to manage those tasks. Sometimes a model running too fast isn't necessarily a good thing." High speed also means errors accumulate faster, requiring developers to review more frequently. That said, for vibe coding scenarios that demand frequent debugging and iteration, this response speed genuinely introduces a new working rhythm.

Hands-On Test 1: How Good Is the Bug-Fixing Capability?

Design Tool Input Field Not Clickable

The test scenario involved a real bug in the BridgeSpace browser: input fields in the design tool couldn't be clicked into. The tester used CleanShot X to screenshot and annotate the problem area, then submitted the screenshot and description to Composer 2.5.

The model quickly identified the issue—a WebView browser-injected Inspector script was interfering with design mode, causing click events to be incorrectly captured.

WebView is a technology component that embeds a web rendering engine into native applications, widely used in cross-platform desktop frameworks like Electron and Tauri. Developers commonly inject JavaScript scripts into WebViews to implement debugging tools (like Inspector), feature enhancements, or data collection. However, this injection mechanism introduces additional listener layers into the host page's event system—when injected scripts intercept DOM events like mouse clicks or keyboard input, native UI components can lose responsiveness—which was exactly the root cause of the unclickable input fields. The fix was completed in one pass, and the bug was resolved on the spot.

Complex Bug: Agent Fails to Launch

The second, trickier bug: after sending prompts to coding assistants like Cloud Code in BridgeSpace, the agent wouldn't start properly. Composer 2.5 didn't fix it on the first attempt, and Opus 4.7 couldn't solve it either.

This is when the tester activated Cursor's Debug Mode—a feature many overlook but find extremely useful in practice. Debug Mode is essentially an agent workflow based on the ReAct (Reasoning + Acting) framework. ReAct is an LLM reasoning paradigm proposed by researchers at Google and Princeton that has models perform explicit chain-of-thought reasoning before executing actions, forming a cycle of "think → act → observe → think again." Specifically, Debug Mode will:

1. Automatically configure monitoring probes (Instrumentation) needed to investigate the bug
2. List multiple hypotheses for what's causing the bug (Hypothesis Generation)
3. Test each hypothesis and record results
4. Confirm the root cause based on logs

This systematic debugging methodology closely mirrors how senior human engineers troubleshoot, and compared to simply having the model "guess and fix"