Claude Opus 4.1 vs Claude Opus 4.5
Terminal-Bench Hard (version unstated) Terminal-Bench Hard (version unstated): Agents solve difficult software, system-administration and data-processing tasks in a terminal
Opus 4.134.3
Opus 4.540.9
AA-LCR (long context) 1.1 AA-LCR (long context) 1.1: Questions that need reading and connecting facts across very long documents (around 100K tokens)
Opus 4.176
Opus 4.570.7
SWE-bench Pro (private) SWE-bench Pro (private): Agents resolve long-horizon professional repository tasks; public and private splits are separate
Opus 4.117.8
Opus 4.523.4
MCP-Atlas Public MCPAtlas Public: MCPAtlas Public as reported in this launch evaluation; the post is the authority for the recorded task and grading scope
Opus 4.1—
Opus 4.5 · high73.4
MCP-Atlas · full 1000 MCP-Atlas · full 1000: Tool orchestration across MCP servers on the stated task split
Opus 4.1—
Opus 4.5 · high69.8
τ³-bench · banking · 1.0.1 τ-bench official · 3-banking-1.0.1: Customer-service agents converse with simulated users, retrieve domain knowledge and change state through tools
Opus 4.1—
Opus 4.5 · high24.7
EBR Bench EBR Bench: Agents learn to play Earthborne Rangers across repeated playthroughs
Opus 4.17.9
Opus 4.5—
| Benchmark | Opus 4.1 | Opus 4.5 |
|---|---|---|
| Terminal-Bench Hard (version unstated) | 34.3 | 40.9 |
| AA-LCR (long context) 1.1 | 76 | 70.7 |
| SWE-bench Pro (private) | 17.8 | 23.4 |
| MCP-Atlas Public | — | 73.4 · high |
| MCP-Atlas · full 1000 | — | 69.8 · high |
| τ³-bench · banking · 1.0.1 | — | 24.7 · high |
| EBR Bench | 7.9 | — |
Specs
| Spec | Opus 4.1 | Opus 4.5 |
|---|---|---|
| Input, per 1M | $15 | $5 |
| Output, per 1M | $75 | $25 |
| Speed, tok/s | — | 51 |
| Context | 200K | 200K |
| Weights | Closed | Closed |
| Released | Aug 2025 | Nov 2025 |
| See images | ✓ | ✓ |
| Read PDFs | Partial | Partial |
| Hear audio | — | — |
| Watch video | — | — |
| Call tools | ✓ | ✓ |
| Force a tool call | Partial | Partial |
| Return strict JSON | — | ✓ |
| Search the web | ? | ? |
| Run code | ? | ? |
| Use a computer | ? | ? |
What breaks when you switch
Opus 4.1 → Opus 4.5
Nothing known.
Opus 4.5 → Opus 4.1