Claude Sonnet 4.6 vs Composer 2.5
Claude Sonnet 4.6 and Composer 2.5 compare a standalone API model against an IDE-native agent. Sonnet has 1M context in beta, computer-use positioning, and broad product integration; Composer has lower standard pricing and Cursor-harness benchmark rows. Treat the result as workflow fit, not a universal model winner.
Pick Sonnet 4.6 when API access, long context, broader tools, or non-Cursor deployment matter. Pick Composer 2.5 when you want the packaged IDE-native agent built on Kimi K2.5 workflow and standard-tier cost dominates. Treat Composer's 79.8% SWE-Bench Multilingual score and Sonnet's SWE-Bench Verified rows as different test sets, not a single leaderboard.
Decision scorecard
Local evidence first| Signal | Claude Sonnet 4.6 | 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 | $15/1M tokens | $2.50/1M tokens |
| Provider routes | 6 tracked | 1 tracked |
| Shared benchmarks | 3 shared | SWE-rebench leader |
Decision tradeoffs
- Claude Sonnet 4.6 has broader tracked provider coverage for fallback and procurement flexibility.
- Claude Sonnet 4.6 uniquely exposes Vision, Multimodal, and Reasoning in local model data.
- Local decision data tags Claude Sonnet 4.6 for Coding, RAG, and Agents.
- Composer 2.5 holds a shared-benchmark lead on SWE-rebench, ahead by 19.1 points.
- 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 Sonnet 4.6
$6,150
Cheapest tracked route/tier: OpenRouter
Composer 2.5
$1,025
Cheapest tracked route/tier: Cursor Standard async
Estimated monthly gap: $5,125. 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 Sonnet 4.6 and Composer 2.5; plan for SDK, billing, or endpoint changes.
- Composer 2.5 is $12.50/1M 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 Sonnet 4.6; plan for SDK, billing, or endpoint changes.
- Claude Sonnet 4.6 is $12.50/1M 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 Sonnet 4.6 adds Vision, Multimodal, and Reasoning in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-02-17 | 2026-05-18 |
| Context window | 1m | 1m |
| Parameters | — | — |
| Architecture | Decoder Only | - |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | 2025-08 | - |
Pricing and availability
| Pricing attribute | Claude Sonnet 4.6 | Composer 2.5 |
|---|---|---|
| Input price | $3/1M tokens |
|
| Output price | $15/1M tokens |
|
| Providers |
Capabilities
| Capability | Claude Sonnet 4.6 | 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 Sonnet 4.6 | Composer 2.5 |
|---|---|---|
| SWE-rebench | 60.7 | 79.8 |
| Terminal-Bench 2.0 | 59.1 | 69.3 |
| SWE-bench Multilingual | 75.9 | 79.8 |
Harness caveat. Composer 2.5 is measured as IDE-native agent built on Kimi K2.5, while Claude Sonnet 4.6 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 comparison is a workflow decision before it is a benchmark decision. Sonnet 4.6 can be used through Anthropic and partner APIs, while Composer 2.5 is packaged inside Cursor. That makes Sonnet a better fit for product integrations, CI agents, server-side automations, and any workflow that needs provider flexibility.
Composer is compelling for Cursor users because its standard token price is $0.50/M input and $2.50/M output, compared with Sonnet 4.6 at $3/M input and $15/M output. For high-volume IDE work where Cursor is already the control plane, that standard-tier gap matters.
The benchmark table needs a caveat. Composer's 79.8% row is SWE-Bench Multilingual, while Sonnet's core coding evidence includes SWE-Bench Verified and Terminal-Bench rows. Those are not the same tasks, and Composer's scores include product and harness assumptions from Cursor.
Sonnet has the broader capability row: 1M-token context in beta, code execution and tool use in Anthropic's platform, and computer-use positioning. Composer is narrower but optimized for long coding sessions inside the IDE, including multi-file edits, terminal commands, search, and autonomous planning.
FAQ
Is Composer 2.5's 79.8% score higher than Sonnet 4.6's SWE-Bench score?
Do not read it that way. Composer's 79.8% is SWE-Bench Multilingual, while Sonnet's main coding rows are SWE-Bench Verified or other Anthropic-reported evaluations. They are different test sets with different harness assumptions.
Which should I use outside Cursor?
Use Sonnet 4.6 outside Cursor. It has API and hosted-provider routes in the seed data, while Composer 2.5 is tracked as Cursor-native and not as a standalone API model.
Which is cheaper for coding work?
Composer 2.5 is cheaper at the standard tier, listed at $0.50/M input and $2.50/M output. Sonnet 4.6 is $3/M input and $15/M output, though it brings broader API availability and a larger sourced context window.
Which has the larger context window?
Sonnet 4.6 has a 1M-token context window in beta in the sourced model row. Composer 2.5 uses Cursor's long-session context management, but the comparison should not treat an undisclosed Cursor agent context as the same as a published API context limit.
Continue comparing
Last reviewed: 2026-06-15. Data sourced from public model cards and provider documentation.