Grok 4.5: Complete Guide to xAI's Coding-Focused Frontier Model (2026)
What is Grok 4.5?
Grok 4.5 is xAI's frontier model built for coding, agentic tasks, and knowledge work. Released on July 8, 2026, it was trained alongside Cursor (acquired by xAI for approximately $60 billion weeks before launch) using real developer session data. It's xAI's first model purpose-built for software engineering and long-horizon agent loops rather than general chat.
Reportedly built on a 1.5-trillion-parameter V9 foundation, Grok 4.5 was trained across tens of thousands of NVIDIA GB300 GPUs in xAI's Memphis data centers. Elon Musk described it as "Opus-class, but faster, more token-efficient, and lower cost."
Grok 4.5 is the default model in Grok Build, xAI's open-source coding agent CLI (licensed Apache 2.0), and is available across all Cursor plans.
Key Features
Agentic Coding Performance
Grok 4.5 excels at real-world software engineering. Its reinforcement learning covers hundreds of thousands of tasks centered on multi-step coding work, with automated and model-based grading. The training stack supports asynchronous learning so agentic rollouts can run for hours while learning continues across tens of thousands of GPUs.
Key published benchmarks (vendor-reported via xAI's official launch):
| Benchmark | Score | What It Measures |
|---|---|---|
| SWE-bench Pro | 64.7% | Hard, multi-file software issues |
| Terminal-Bench 2.1 | 83.3% | Command-line terminal workflows |
| DeepSWE 1.0 | 62.0% | End-to-end repository-level coding |
| SWE Marathon | 29.0% | Long-horizon agentic coding tasks |
| SWE-bench Multilingual | 78.0% | Cross-language coding ability |
Independent testing by Artificial Analysis placed Grok 4.5 at 54 on its Intelligence Index (#4 overall at launch, #1 on agentic tool use). On Snorkel's GDPVal+ evaluation of professional workplace tasks, Grok 4.5 achieved a 29% pass rate versus 22% for GPT-5.5 and 21% for Claude Opus 4.8.
Token Efficiency
Grok 4.5's standout advantage is how few tokens it spends. On SWE-bench Pro, it averages approximately 15,954 output tokens per resolved task — versus 67,020 for Claude Opus 4.8. The model achieves roughly 2x the token efficiency of comparable models, solving tasks in under half the steps.
| Model | Output Tokens per SWE-bench Pro Task |
|---|---|
| Grok 4.5 | ~15,954 |
| Claude Opus 4.8 | ~67,020 |
This efficiency compounds with its low per-token price to deliver the lowest cost per completed coding task among frontier models.
Reasoning Control
Grok 4.5 supports configurable reasoning effort — low, medium, or high (default high). This lets you trade cost and latency against accuracy per request:
- High: Maximum accuracy on complex agentic tasks
- Medium: Balanced speed and quality
- Low: Fastest response for simple queries
Native Tool Ecosystem
Grok 4.5 ships built-in tool support without extra orchestration:
- Function calling: Call external APIs and tools directly
- Web search: Real-time internet retrieval
- X search: Direct access to X/Twitter data
- Code execution: Run code within the agent loop
- Structured outputs: Strict JSON schema mode
- Document search: RAG-style file retrieval across collections
Office Integration
Grok 4.5 is available as the default model in Microsoft Office add-ins. It can build complex Excel models involving multi-sheet formulas with notes, design native PowerPoint diagrams with shapes, and write clear Word documents.
Pricing
Grok 4.5 uses a two-tier pricing structure based on prompt length:
| Tier | Input (per 1M tokens) | Cached Input (per 1M) | Output (per 1M) |
|---|---|---|---|
| ≤200K context | $2.00 | $0.30 (85% discount) | $6.00 |
| >200K context | $4.00 | $1.00 | $12.00 |
Additional tool costs apply separately:
| Tool | Cost |
|---|---|
| Web search | $5 / 1,000 calls |
| X search | $5 / 1,000 calls |
| Code execution | $5 / 1,000 calls |
| File/collection search | $2.50 / 1,000 calls |
Grok 4.5 is also available through Cursor, Grok Build, OpenRouter, Vercel AI Gateway, Cloudflare Workers AI, Snowflake Cortex, and Databricks Mosaic AI.
Cost Comparison vs Competitors
| Model | Input/Output per 1M | Cost per Coding Agent Task |
|---|---|---|
| Grok 4.5 | $2 / $6 | ~$2.49 |
| GPT-5.5 (Codex) | $5 / $30 | ~$5.07 |
| Claude Fable 5 | $10 / $50 | ~$11.80 |
| Claude Opus 4.8 | $5 / $25 | Not available |
Per-task cost data from Artificial Analysis. Grok 4.5 achieves near-equivalent coding performance at roughly half the cost of GPT-5.5 and less than a quarter the cost of Claude Fable 5.
Who Is Grok 4.5 Best For?
- Software engineers building agentic coding tools: Best-in-class value for high-volume, long-session coding agents
- Teams running CI/CD automation: Low cost per resolved task makes it ideal for automated code review and fixing
- Developer tool startups: Aggressive pricing and strong terminal performance suit budget-conscious teams
- Knowledge workers using Office tools: Excel, PowerPoint, and Word integration is uniquely polished
Limitations
- Context window: 500K tokens is a reduction from Grok 4.3's 1M — a rare regression for long-document work
- Unpublished academic benchmarks: No GPQA Diamond, AIME, or MMLU-Pro scores released at launch
- EU launch delay: Blocked at July 8 launch for EU AI Act evaluations; resolved July 16, now fully available in Europe
- Text-only output: No native image, audio, or video generation
- Closed-weight: API-only access, no self-hosting
- Safety documentation thinner: Unlike Grok 4.1 and 4.20, no system card published at launch (a model card was released July 14, 2026)
Grok 4.5 vs Competitors
| Aspect | Grok 4.5 | Claude Opus 4.8 | GPT-5.5 | Gemini 3.5 |
|---|---|---|---|---|
| Input price / 1M | $2.00 | $5.00 | $5.00 | $1.25 |
| Output price / 1M | $6.00 | $25.00 | $30.00 | $10.00 |
| Context window | 500K | 200K | 256K | 2M |
| SWE-bench Pro | 64.7% | 69.2% | 58.6% | Not published |
| Terminal-Bench 2.1 | 83.3% | Not published | Not published | Not published |
| Image input | Yes | Yes | Yes | Yes |
| Image output | No | No | Yes (DALL-E) | Yes (Imagen) |
| Speed | ~80 TPS | Not published | Not published | Fastest |
| EU availability | Full (from Jul 16) | Full | Full | Full |
The Bottom Line
Grok 4.5 is the strongest value proposition in frontier AI for coding and agentic tasks. It doesn't win every benchmark, but it doesn't need to — its combination of competitive scores, drastically lower cost, and superior token efficiency makes it the most practical choice for high-volume development workloads.
If you need the absolute highest raw accuracy on a single hard task, Claude Opus 4.8 or Claude Fable 5 is still ahead. But if you're running agents at scale, Grok 4.5's cost per completed task is unmatched.
Related Articles
Frequently Asked Questions
Is Grok 4.5 free to use?+
How does Grok 4.5 compare to Claude Opus 4.8?+
What is the context window of Grok 4.5?+
Can Grok 4.5 generate images?+
When will Grok 4.6 and 4.7 be released?+
Pros
- Aggressive pricing at $2/$6 per 1M tokens
- Excellent token efficiency — uses 4x fewer output tokens than rivals on coding tasks
- Strong agentic coding and terminal performance
- Native function calling, web search, X search, and code execution
- Available in Cursor, Grok Build, and major model gateways
Cons
- 500K context window is smaller than Grok 4.3's 1M
- No published GPQA, AIME, or MMLU-Pro benchmarks at launch
- Delayed EU launch (resolved July 16)
- No native image, audio, or video output
- Closed-weight — no self-hosting option
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