Claude Sonnet 5.5 vs GPT-6.1 Sol

$0.88 / task
Wins 1 of 9 benchmarks
$0.21 / task
Wins 6 of 9 benchmarks
Different efforts: high · medium · Compare all at high
Terminal-Bench 4.0 Terminal-Bench 4.0 · source setting 2: Agents use a terminal to complete executable coding, system administration and research tasks in the 4.0 suite
Sonnet 5.543.9
GPT-6.1 Sol48
DeepSWE 1.1 DeepSWE 1.1: Agents change repository code to resolve software engineering tasks under the stated DeepSWE edition
Sonnet 5.5 · max70.5
GPT-6.1 Sol · max72.3
FrontierCode 1.1 FrontierCode 1.1: Agents implement changes in real repositories, graded against maintainer-defined requirements
Sonnet 5.544.3
GPT-6.1 Sol · max49.1
WebDev Arena WebDev Arena: Human pairwise preferences in the stated webdev vote pool
Sonnet 5.51,710
GPT-6.1 Sol · max1,753
SWE-bench Pro (v2 full) SWE-bench Pro (v2 full): Agents resolve repository issues under the network-locked v2 protocol; full and 51-task Hard results are separate
Sonnet 5.5 · xhigh95.8
GPT-6.1 Sol · xhigh96.1
SciCode SciCode: Writing code for real scientific computing problems (physics, biology, math)
Sonnet 5.553.7
GPT-6.1 Sol53.2
Terminal-Bench Science 0.1 Terminal-Bench Science 0.1: Agents complete expert-authored research workflows across five scientific domains in a terminal
Sonnet 5.534.3
GPT-6.1 Sol · max58.1
SWE-bench Pro (v2 hard) SWE-bench Pro (v2 hard): Agents resolve repository issues under the network-locked v2 protocol; full and 51-task Hard results are separate
Sonnet 5.5 · xhigh70.6
GPT-6.1 Sol—
MultiLangBenchlab MultiLangBench: Models build a SQLite-compatible database engine in 20 programming languages
Sonnet 5.5—
GPT-6.1 Sol67.5

Specs

SpecSonnet 5.5GPT-6.1 Sol
Input, per 1M$2$2
Output, per 1M$10$10
Cost per task?$0.88$0.21
Speed, tok/s10645
Context1M1.05M
WeightsClosedClosed
ReleasedSep 2026Sep 2026
See images✓✓
Read PDFs✓Partial
Hear audio——
Watch video——
Call tools✓✓
Force a tool call—Partial
Return strict JSON✓✓
Search the web✓✓
Run code✓✓
Use a computer✓✓

What breaks when you switch

Sonnet 5.5 → GPT-6.1 Sol
Remove unsupported parameters›

With reasoning enabled, remove temperature, top_p and top_logprobs, plus Chat Completions logprobs or Responses message.output_text.logprobs includes.

Responses API for tool calling · Chat Completions›

Use Responses for tools; Chat Completions supports this model without tool calling.

No none or minimal reasoning›

The none and minimal reasoning efforts are unsupported; choose low, medium, high, xhigh or max.

More than 272K input tokens›

Prompts above 272K input tokens charge 2× input and cache rates and 1.5× output rates for the entire request.

Cache writes billed at 1.25x›

Cache writes cost 1.25× the uncached input token rate.

Ultrafast prices 6x Standard›

Ultrafast mode costs 6× Standard token prices.

GPT-6.1 Sol → Sonnet 5.5
Context: 1.05M → 1M
No forced tool use›

Forced tool_choice any or tool returns HTTP 400; remove the forced choice.

Replace disabled thinking›

Disabled thinking returns HTTP 400; use between_tools for the lowest thinking setting.

No manual thinking budgets›

Manual thinking budgets and extra between_tools fields return HTTP 400; remove manual budgets and send between_tools without display, budget_tokens or block_binding.

Remove sampling parameters›

Non-default temperature, top_p or top_k returns HTTP 400; remove these parameters.

No assistant prefill›

A prefilled final assistant turn returns HTTP 400; remove that prefill.

Old computer tool rejected · Claude API / Google Cloud›

The computer_20251124 tool returns HTTP 400 on the Claude API and Google Cloud; use computer_toolset_20260801 there.