Who this is for: engineering leads evaluating AI coding model switch costs, Cursor subscribers, and FinOps owners tracking token efficiency and API bills. On July 8, 2026, Elon Musk's SpaceXAI shipped Grok 4.5 — its first flagship model since going public — with a pitch of "Opus-class intelligence at one-quarter the price." You get: core specs, API and per-task pricing, four coding benchmark rows, agent-task highlights, TryAI hands-on results, platform access and cache best practices, a fit/caution matrix, and six FAQs. Structure: pain points, model positioning, pricing, benchmarks, real-world tests, access, selection, runbook, close. For a broader four-way comparison, see our AI coding assistant decision matrix.
TL;DR — 30-second verdict
After Musk's X posts, most engineering teams are stuck on six decision blind spots — not whether Grok 4.5 exists, but how to turn marketing into an actionable selection case:
The sections below use public benchmarks, independent reviews, and pricing arithmetic to close each gap.
SpaceXAI released Grok 4.5 on July 8, 2026 — its first flagship product since going public. This is not a routine version bump: the model is tuned for coding and code agents, agentic workflows, and knowledge-intensive work (legal, healthcare, education, data analysis).
The biggest shift: co-training with Cursor, injecting trillions of tokens of real developer interactions — code review, debugging flows, and agent-to-codebase sessions. SpaceX completed its Anysphere acquisition in June 2026; this co-training is among the first outputs.
| Parameter | Value |
|---|---|
| Architecture | Mixture of Experts (MoE) |
| Context window | 500,000 tokens (500K) |
| Reasoning modes | Low / Medium / High (default: High) |
| Inference speed | 80 TPS official, ~90 TPS measured; first token <0.5s, ~110 tokens/sec stream rate |
| Training hardware | Tens of thousands of NVIDIA GB300 GPUs (Memphis data center) |
| Parameter count | Not disclosed (MoE architecture) |
Cost is Grok 4.5's core pitch. Start with API unit rates, then fold in token efficiency for actual per-task agent spend.
| Model | Input | Output |
|---|---|---|
| Grok 4.5 | $2.00 | $6.00 |
| Grok 4.5 (cache hit) | $0.50 | — |
| Grok 4.5 Fast | $4.00 | $18.00 |
| Claude Opus 4.7 | $5.00 | $25.00 |
| Claude Fable 5 | Higher | Higher |
| GPT-5.6 Sol (flagship) | $5.00 | $30.00 |
| GPT-5.6 Luna (economy tier) | $1.00 | $6.00 |
| Model / platform | Avg tokens per task | Estimated cost per task |
|---|---|---|
| Grok 4.5 / Grok Build | ~1.9M tokens | $2.49 |
| GPT-5.5 / Codex | ~6.2M tokens | $5.07 |
| Claude Fable 5 / Claude Code | ~7.2M tokens | $11.80 |
Token efficiency key point: on SWE-Bench Pro coding tasks, Grok 4.5 averages 15,954 output tokens per run; Claude Opus 4.8 uses 67,020 for the same tasks — a 4.2x gap. At 500 tasks per day, that is roughly $1,245 vs $5,900 daily. High-frequency call patterns compound the advantage fast.
SpaceXAI published four coding-related evaluations at launch. Below is the official data plus third-party runs, with harness differences called out.
| Benchmark | Grok 4.5 | Claude Fable 5 | Claude Opus 4.8 | GPT-5.5 |
|---|---|---|---|---|
| DeepSWE 1.0 (provider harness) | 62.0% | 66.1% | 55.75% | 64.31% |
| DeepSWE 1.1 (neutral harness) | 53% | 70% | 59% | 67% |
| Terminal Bench 2.1 | 83.3% | 84.3% | 78.9% | 83.4% |
| SWE-Bench Pro (resolve rate) | 64.7% | 80.4% | 69.2% | 58.6% |
How to read these numbers:
CursorBench withdrawal: at launch, CursorBench (Cursor's own eval set) was temporarily removed — a snapshot of Cursor's codebase had accidentally entered Grok 4.5 training data, creating a data contamination risk. This is a notable launch blemish; related performance numbers should not be cited until independent re-testing lands.
| Benchmark | Grok 4.5 | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|---|
| AutomationBench-AA (657 enterprise workflow tasks) | 51.4% | 48.6% | 48.5% |
| Snorkel GDPVal+ (professional work composite) | 29% | — | 21% |
AutomationBench-AA spans 40 simulated enterprise apps including Gmail, Slack, Salesforce, and HubSpot. Grok 4.5 is the first model to complete more than half of workflow objectives without violating business constraints.
On Snorkel's professional-scenario evaluation, Grok 4.5 leads by wide margins:
Artificial Analysis Intelligence Index: 54 (fourth place), behind Fable 5 (60), Opus 4.8 (56), and GPT-5.5 (55). Still a 16-point jump over the prior Grok generation.
Independent tester TryAI gave Grok 4.5, GPT-5.5, Claude Opus 4.8, and Claude Fable 5 identical prompts to build the same interactive app from scratch.
3D cube rendering (hardest test):
Speed and cost: Grok 4.5 delivered first token in under 0.5 seconds at ~110 tokens/sec (roughly 2x competitors) and was the cheapest run in every test. Fable 5 was slowest and most expensive.
Bottom line: for high-volume repetitive codegen where speed and cost compound, Grok 4.5 is hard to beat. For complex stateful UI that must land correctly on the first attempt, Claude models remain more reliable.
Grok 4.5 is live on the platforms below (EU availability expected mid-July):
us-east-1, us-west-2; rate limits: 150 req/s, 50M tokens/mincurl -s https://api.x.ai/v1/responses \
-H "Authorization: Bearer $XAI_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "grok-4.5",
"input": "Find and fix the bug: function median(a){a.sort();return a[a.length/2]}"
}'
Best practices:
prompt_cache_key (Responses API) or the x-grok-conv-id header (Chat Completions) so conversations route to the same server — cache hits drop input pricing to $0.50/M tokens.| Scenario | Recommendation | Rationale |
|---|---|---|
| High-frequency agent tasks (hundreds to thousands/day) | Good fit — Grok 4.5 | $2.49 vs $11.80 per task; savings show up immediately |
| Terminal / tool-calling work | Good fit | Top-tier Terminal Bench 2.1 and AutomationBench results |
| Teams already deep in Cursor | Good fit | Co-trained, native support, frictionless switch |
| Mixed-model strategy | Recommended | Route routine subtasks to Grok 4.5; reserve architecture decisions for Fable 5 |
| SWE-Bench Pro-grade precision code | Use caution | Fable 5 leads by ~16 points; gap is real |
| Hallucination-sensitive production systems | Use caution | AA-Omniscience hallucination rate 54%; enforce output validation |
| EU-based teams | Use caution | API limited to us-east-1 / us-west-2 until mid-July |
| CursorBench-related claims | Use caution | Training contamination; scores withdrawn pending re-test |
prompt_cache_key or x-grok-conv-id on long sessions and track hit rate vs bill.Grok 4.5 is not the most accurate coding model in mid-2026, but it is the best intelligence-per-dollar Opus-class coding agent for agentic workflows. The real value is not benchmark #1 — it is what happens when you multiply token efficiency by API pricing: Grok 4.5 often delivers Opus 4.8-adjacent quality at 70–80% lower per-task cost on mainstream agent pipelines.
Running high-frequency agent loops on a local MacBook still hits three structural bottlenecks:
To run a stable Grok 4.5 + Cursor agent stack, OpenClaw Gateway, or multi-model routing pipeline, MACCOME Mac cloud hosts provide real macOS, SSH handoff, and isolated environments for 24/7 agent nodes. See Mac mini cloud rental pricing for current tiers.
Sources: SpaceXAI official announcement, Cursor co-launch post, SpaceXAI API docs, TechCrunch, Awesome Agents independent review, APIdog benchmark analysis, Snorkel AI professional evaluation. Data current as of July 10, 2026; capabilities and pricing may change.
FAQ
Is Grok 4.5 better than Claude Opus 4.8?
It depends what "better" means. Claude Opus 4.8 wins on raw coding accuracy (SWE-Bench Pro: 69.2% vs 64.7%). Grok 4.5 wins on speed, token efficiency, and per-task cost — often by a 4x margin. On agentic workflow completion, independent benchmarks also slightly favor Grok 4.5 over Opus 4.8.
Can I use Grok 4.5 for free?
SpaceXAI offers limited free usage in Grok Build and Cursor for a limited time. After that, API pricing is $2/M input and $6/M output. Cursor subscription plans include Grok 4.5 in the model pool.
How do I use Grok 4.5 in Cursor?
Grok 4.5 is available on all Cursor plans automatically. Open Cursor, go to model selection, and choose Grok 4.5. Usage was doubled for the first week after launch. For broader IDE comparison, see our AI coding assistant decision matrix.
What is Grok 4.5's context window?
500,000 tokens (500K), which is large enough for most large codebase tasks.
Why was CursorBench removed from the launch?
A snapshot of Cursor's own codebase was accidentally included in Grok 4.5's training data, contaminating that benchmark. SpaceXAI pulled those results; independent re-testing is expected.
Is Grok 4.5 available via OpenRouter?
Yes. Grok 4.5 is accessible through OpenRouter, Vercel AI Gateway, Cloudflare, Snowflake, and Databricks Mosaic. For a 24/7 agent node running mixed routing, see MACCOME Mac cloud rental plans.