Claude Opus 4.8 vs Composer 2.5
Claude Opus 4.8 and Composer 2.5 answer different decisions. Opus 4.8 is a generally available API model for coding, computer use, and long-horizon agents; Composer 2.5 is a Cursor-native coding agent built on Kimi K2.5 and evaluated inside Cursor's product context.
Pick Claude Opus 4.8 when you need API access, independent production integration, computer-use capability, or the strongest verified coding signal in this pair. Pick Composer 2.5 when your work lives inside Cursor and token cost matters: its standard tier is roughly one tenth of Opus 4.8 input pricing. Do not compare Composer's 79.8% SWE-Bench Multilingual number as if it were an Opus SWE-Bench Verified score.
Decision scorecard
Local evidence first| Signal | Claude Opus 4.8 | Composer 2.5 |
|---|---|---|
| Product type | Standalone API model | IDE-native agent built on Kimi K2.5 |
| Best for | API builders, multimodal apps, and non-IDE automation | Long Cursor IDE sessions and autonomous in-IDE coding |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 1m | 1m |
| Cheapest output | $25/1M tokens | $2.50/1M tokens |
| Provider routes | 6 tracked | 1 tracked |
| Shared benchmarks | CursorBench leader | 1 shared |
Decision tradeoffs
- Claude Opus 4.8 holds a shared-benchmark lead on CursorBench, ahead by 0.6 points.
- Claude Opus 4.8 has broader tracked provider coverage for fallback and procurement flexibility.
- Claude Opus 4.8 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Claude Opus 4.8 for Coding, RAG, and Agents.
- Composer 2.5 has the lower cheapest tracked output price at $2.50/1M tokens.
- Composer 2.5 uniquely exposes IDE integration in local model data.
- Local decision data tags Composer 2.5 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Claude Opus 4.8
$10,250
Cheapest tracked route/tier: Anthropic
Composer 2.5
$1,025
Cheapest tracked route/tier: Cursor Standard async
Estimated monthly gap: $9,225. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Claude Opus 4.8 and Composer 2.5; plan for SDK, billing, or endpoint changes.
- Composer 2.5 is $22.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Vision, Multimodal, and Reasoning before moving production traffic.
- Composer 2.5 adds IDE integration in local capability data.
- No overlapping tracked provider route is sourced for Composer 2.5 and Claude Opus 4.8; plan for SDK, billing, or endpoint changes.
- Claude Opus 4.8 is $22.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for IDE integration before moving production traffic.
- Claude Opus 4.8 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-05-28 | 2026-05-18 |
| Context window | 1m | 1m |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Weights | Not released | Not released |
| Code | Not released | Not released |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | 2026-01 | - |
Pricing and availability
| Pricing attribute | Claude Opus 4.8 | Composer 2.5 |
|---|---|---|
| Input price | $5/1M tokens |
|
| Output price | $25/1M tokens |
|
| Providers |
Capabilities
| Capability | Claude Opus 4.8 | Composer 2.5 |
|---|---|---|
| Vision | Yes | No |
| Multimodal | Yes | No |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | Yes |
| Structured outputs | Yes | No |
| Code execution | Yes | Yes |
| IDE integration | No | Yes |
| Computer use | Yes | No |
| Parallel agents | Yes | Yes |
Benchmarks
| Benchmark | Claude Opus 4.8 | Composer 2.5 |
|---|---|---|
| CursorBench | 63.8 | 63.2 |
Harness caveat. Composer 2.5 is measured as IDE-native agent built on Kimi K2.5, while Claude Opus 4.8 is standalone API model. Treat shared benchmark scores as directional because IDE or product scaffolding, tool access, prompt routing, and interaction mode can change real application results.
Deep dive
The benchmark caveat is the center of this comparison. Opus 4.8 has a sourced SWE-Bench Verified row at 88.6% and SWE-Bench Pro at 69.2%. Composer 2.5's widely cited 79.8% number is SWE-Bench Multilingual from Cursor's agent context, not SWE-Bench Verified, so it should not be used to claim Composer trails or beats Opus on the Verified leaderboard.
Deployment surface is just as important as score. Opus 4.8 can be called through the Claude API and tracked provider routes, while Composer 2.5 is available through Cursor rather than as a standalone model API. Product teams building CI agents, backend automations, or non-Cursor IDE tools need Opus or another API model.
Composer's advantage is workflow fit and cost inside Cursor. The standard price row is $0.50/M input and $2.50/M output, while Opus 4.8 standard pricing is $5/M input and $25/M output. Cursor users can justify Composer first for interactive IDE tasks if they accept the product-bound harness and benchmark caveats.
Opus 4.8 has the stronger computer-use and general agent surface in the sourced records. Its seed rows include OSWorld-Verified and Terminal-Bench 2.1, and Anthropic's launch material emphasizes dynamic workflows, parallel subagents, mid-task system messages, and reduced unflagged code flaws. Composer is narrower: a strong Cursor coding agent, not a general provider route.
FAQ
Does Composer 2.5 have a SWE-Bench Verified score?
No sourced seed row here gives Composer 2.5 a SWE-Bench Verified score. Its 79.8% figure is SWE-Bench Multilingual in Cursor's product context, which is a different benchmark and should not be compared directly with Opus 4.8's Verified score.
Which is better for Cursor users?
Composer 2.5 is the natural first test inside Cursor because it is Cursor-native, cheaper at the standard tier, and tuned for IDE workflows. Opus 4.8 is still the stronger escalation path when a task needs external API access, computer-use breadth, or verified benchmark confidence.
Which is cheaper, Opus 4.8 or Composer 2.5?
Composer 2.5 is much cheaper at standard pricing: $0.50/M input and $2.50/M output versus Opus 4.8 at $5/M input and $25/M output. Composer's fast tier narrows the gap but remains tied to Cursor usage.
Can I use Composer 2.5 through an API?
Not in the tracked provider data. Composer 2.5 is represented as a Cursor-native agent product, while Opus 4.8 has normal API and hosted-provider routes for production integrations.
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Last reviewed: 2026-06-30. Data sourced from public model cards and provider documentation.