Bottom line: Grok 4.5 is not the highest-scoring coding model on every benchmark, but it is the strongest value play in the Opus-class tier — roughly one-quarter the per-task cost of Claude Code when you factor in token efficiency, not just list price.
On July 8, 2026, Elon Musk's SpaceXAI shipped Grok 4.5, its first flagship model since going public. Musk called it on X an "Opus-class model that is faster, more token-efficient, and cheaper."
This review is for engineering teams evaluating AI coding assistants, Cursor subscribers, and budget-conscious platform owners. We pull together public benchmarks, TryAI's independent coding tests, API pricing, and platform access paths to answer three questions: where Grok 4.5 wins, where it falls short, and whether the "4x cheaper" claim holds up in real arithmetic.
01 What is Grok 4.5? Cursor co-training and core specs
Common evaluation mistakes:
- Ranking by a single benchmark table: Vendor harnesses and neutral harnesses can diverge by 17 percentage points on the same test.
- Comparing API list prices only: When output token consumption differs 4.2x, a cheaper sticker price does not mean a cheaper task.
- Ignoring training-data controversy: CursorBench was pulled over contamination risk — Cursor-related claims need independent re-testing.
- Skipping hallucination checks: The AA-Omniscience Index puts Grok 4.5 at a 54% hallucination rate; production workflows need validation gates.
Grok 4.5 is SpaceXAI's strongest model to date, tuned for three workload classes:
- Coding and code agents: Bug fixes, large-repo refactors, end-to-end app builds
- Agentic workflows: Multi-step automation across tools and applications
- Knowledge-intensive work: Legal, medical, education, and data-analysis tasks
Unlike prior Grok releases, this model was co-trained with Cursor on trillions of tokens of real developer interactions — code reviews, debugging sessions, and agent-to-codebase traces. SpaceX completed its acquisition of Cursor parent Anysphere in June 2026; this co-training is one of the first outputs of that deal. For background, see our SpaceX Cursor acquisition deep dive.
| 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 |
| Training hardware | Tens of thousands of NVIDIA GB300 GPUs (Memphis data center) |
| Parameter count | Not disclosed (MoE architecture) |
02 Grok 4.5 pricing: API rates and real per-task costs
Pricing is Grok 4.5's sharpest selling point. Start with per-million-token API rates, then fold in token efficiency to get actual task economics.
| 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) | $1.00 | $6.00 |
| Model / platform | Avg tokens per task | Actual 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 |
On SWE-Bench Pro coding tasks, Grok 4.5 averages 15,954 output tokens per run. Claude Opus 4.8 consumes 67,020 on the same task — a 4.2x gap. At 500 tasks per day, Grok runs about $1,245/day versus roughly $5,900/day on Claude Code. The efficiency advantage compounds fast at high call volume.
03 Grok 4.5 benchmarks: coding, agents, and composite intelligence
SpaceXAI published four coding benchmarks at launch. Below we consolidate official numbers with third-party tests and flag why CursorBench was removed.
| Benchmark | Grok 4.5 | Claude Fable 5 | Claude Opus 4.8 | GPT-5.5 |
|---|---|---|---|---|
| DeepSWE 1.0 (vendor 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:
- DeepSWE 1.0 (each vendor's own harness): Grok 4.5 places third — close, but not leading.
- DeepSWE 1.1 (neutral harness): Grok 4.5 drops to fourth; Fable 5 leads by 17 points — the most honest cross-vendor comparison.
- Terminal Bench 2.1: All four top models sit within 5.4 points — effectively a tie.
- SWE-Bench Pro: The hardest test. Grok 4.5 ranks third, roughly 16 points behind Fable 5.
CursorBench removal: At launch, CursorBench (Cursor's proprietary eval set) was temporarily pulled — partial snapshots of Cursor's own codebase had leaked into Grok 4.5 training data, creating contamination risk. Treat any CursorBench-related performance claims as unverified until independent re-tests land.
| Benchmark | Grok 4.5 | Claude Fable 5 | Claude Opus 4.8 |
|---|---|---|---|
| AutomationBench-AA (657 enterprise workflows) | 51.4% | 48.6% | 48.5% |
| Snorkel GDPVal+ (professional work scenarios) | 29% | — | 21% |
AutomationBench-AA simulates 40 enterprise apps — Gmail, Slack, Salesforce, HubSpot, and more. Grok 4.5 is the first model to complete more than half of workflow goals without violating business constraints. On Snorkel's professional scenarios, Grok 4.5 leads sharply in law (40% vs 27–28%), education (58% vs 35–42%), and healthcare (35% vs 23–25%).
Artificial Analysis composite index: Grok 4.5 scores 54 (fourth place) — behind Fable 5 (60), Opus 4.8 (56), and GPT-5.5 (55) — but up 16 points from the previous Grok generation.
04 Grok 4.5 in practice: TryAI tests and six-step Cursor / API setup
Independent tester TryAI gave Grok 4.5, GPT-5.5, Claude Opus 4.8, and Claude Fable 5 the same prompt to build an identical interactive app from scratch.
| Model | Result |
|---|---|
| Opus 4.8 / Fable 5 | Succeeded on first attempt |
| Grok 4.5 | First attempt rendered title and button only — no cube; succeeded on retry |
| GPT-5.5 | Failed |
Speed and cost: Grok 4.5 delivers first token in under 500ms and streams at roughly 110 tokens/second — about 2x competitors. GPT-5.5 wins on short-answer latency; Fable 5 is slowest and most expensive. For high-frequency repetitive coding, Grok 4.5's speed and cost edge is decisive. For complex state management that must work on the first try, Claude still wins.
Where to access Grok 4.5 (EU expected mid-July 2026):
- Grok Build: SpaceXAI's own coding agent platform; Grok 4.5 is the default model
- Cursor: Available on all subscription tiers (desktop, web, iOS, CLI, SDK); doubled usage limits for the first week after launch
- SpaceXAI Console API: Chat Completions and Responses API
- Office plugins: Default model in Word, PowerPoint, and Excel
- Third-party gateways: OpenRouter, Vercel, Cloudflare, Snowflake, Databricks Mosaic
API regions: us-east-1 and us-west-2. Rate limits: 150 requests/second, 50M tokens/minute.
curl -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 the bug in this code and fix it: function median(a){a.sort();return a[a.length/2]}"
}'Six-step production setup:
- Register on SpaceXAI Console: Create an account at console.x.ai, generate an API key, and confirm billing region is us-east-1 or us-west-2.
- Switch models in Cursor: Open Cursor, go to model picker, select Grok 4.5; use the first-week doubled quota to stress-test real workflows.
- Configure cache keys: Set
prompt_cache_keyon the Responses API, or add anx-grok-conv-idheader on Chat Completions — cache hits drop input pricing to $0.50/M tokens. - Enable context compaction for long agent loops: Reduces token accumulation and keeps high-frequency task costs predictable.
- Route models by task difficulty: Run routine subtasks on Grok 4.5; reserve Claude Fable 5 for hard architecture decisions — configure fallbacks in Cursor or LiteLLM.
- Validate production output: For SWE-Bench Pro-grade precision and hallucination-sensitive flows, add CI test gates and human review — do not ship first-pass output blindly.
05 Should you switch to Grok 4.5? Decision matrix, FAQ, and verdict
| Scenario | Recommendation | Rationale |
|---|---|---|
| High-frequency agent tasks (hundreds to thousands per day) | Strong fit | ~$2.49 vs $11.80 per task — savings show up immediately |
| Terminal work and tool calling | Strong fit | Top-tier Terminal Bench 2.1 and AutomationBench scores |
| Teams already deep in Cursor | Strong fit | Co-trained model, native support, frictionless switch |
| Mixed-model routing strategy | Recommended | Grok 4.5 for routine subtasks; Claude Fable 5 for hardest architecture calls |
| SWE-Bench Pro-grade precision coding | Use with caution | Fable 5 leads by ~16 points — gap is real |
| Hallucination-sensitive production systems | Use with caution | AA-Omniscience hallucination rate at 54%; add verification layers |
| EU-based users | Wait | API limited to us-east-1 / us-west-2; EU not yet open |
| CursorBench-related claims | Hold judgment | Training data contamination; results withdrawn pending re-test |
Citable data points (EEAT):
- Token efficiency ratio: SWE-Bench Pro output tokens — Grok 4.5 at 15,954 vs Opus 4.8 at 67,020, a 4.2x gap (source: SpaceXAI launch data, 2026-07-08).
- Inference speed: First token under 500ms; measured throughput ~110 tokens/s, roughly 2x competitors (source: TryAI independent review).
- Composite intelligence index: Artificial Analysis score of 54, up 16 points from prior Grok, ranked fourth (source: Artificial Analysis, July 2026).
Frequently asked questions:
- Q: Is Grok 4.5 better than Claude Opus 4.8? A: It depends on the metric. Opus 4.8 leads on SWE-Bench Pro accuracy (69.2% vs 64.7%). Grok 4.5 wins on speed, token efficiency, and per-task cost — often by 4x. On agent workflow completion rates in independent benchmarks, Grok 4.5 edges Opus 4.8 slightly.
- Q: Is Grok 4.5 free? A: Grok Build and Cursor offered limited free quotas at launch. API pricing is $2/M input and $6/M output. Cursor subscription tiers include Grok 4.5 in the model pool.
- Q: How do I use Grok 4.5 in Cursor? A: All Cursor plans get access automatically — select Grok 4.5 in the model picker. Usage limits are doubled for the first week after launch.
- Q: What is the context window? A: 500,000 tokens (500K) — enough for most large codebases in a single session.
- Q: Why was CursorBench removed? A: Cursor codebase snapshots accidentally entered training data, contaminating that benchmark. SpaceXAI withdrew the results and is awaiting independent re-testing.
- Q: Can I access Grok 4.5 through OpenRouter? A: Yes — also available via Vercel AI Gateway, Cloudflare, Snowflake, and Databricks Mosaic.
Verdict: Grok 4.5 is not the top coding model on every leaderboard, but it is the best-value Opus-class coding agent available today. When you translate token efficiency and API pricing into per-task cost, it can deliver Opus 4.8-adjacent quality on mainstream agent workflows at 70–80% lower spend. For financial code and security-critical systems, Claude Fable 5 remains the safer default.
Primary sources — re-open these links after any upstream release or page update:
https://cursor.com/blog/grok-4-5
https://docs.x.ai/developers/models/grok-4.5
Running Grok 4.5 on a personal laptop still has hard limits: sleep interrupts long agent loops, parallel repos fight for local resources, and enterprises struggle to unify audit trails and 24/7 uptime. For production environments that need Cursor Agent, Codex CI, or OpenClaw Gateway running reliably around the clock, CALMVPS bare-metal Mac Mini rental is usually the better fit: dedicated Apple Silicon, native Metal acceleration, flexible monthly billing, and ~120-second provisioning let you offload heavy agent compute to the cloud while keeping plan review on your local machine. See the pricing page.