Claude Sonnet 5.5 vs Gemini 4 Argon

$0.88 / task

Wins 2 of 8 benchmarks

$1.99 / task

Wins 5 of 8 benchmarks

Only shared

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

Gemini 4 Argon57.1

FrontierCode 1.1 FrontierCode 1.1: Agents implement changes in real repositories, graded against maintainer-defined requirements

Sonnet 5.544.3

Gemini 4 Argon43.5

WebDev Arena WebDev Arena: Human pairwise preferences in the stated webdev vote pool

Sonnet 5.51,710

Gemini 4 Argon1,678

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

Gemini 4 Argon99.2

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

Gemini 4 Argon92.2

SciCode SciCode: Writing code for real scientific computing problems (physics, biology, math)

Sonnet 5.553.7

Gemini 4 Argon61.8

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

Gemini 4 Argon52.9

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

Gemini 4 Argon—

Benchmark	Sonnet 5.5	Gemini 4 Argon
Terminal-Bench 4.0	43.9	57.1
FrontierCode 1.1	44.3	43.5
WebDev Arena	1,710	1,678
SWE-bench Pro (v2 full)	95.8 · xhigh	99.2
SWE-bench Pro (v2 hard)	70.6 · xhigh	92.2
SciCode	53.7	61.8
Terminal-Bench Science 0.1	34.3	52.9
DeepSWE 1.1	70.5 · max	—

Specs

Spec	Sonnet 5.5	Gemini 4 Argon
Input, per 1M	$2	!$2
Output, per 1M	$10	!$10
Cost per task?	$0.88	$1.99
Speed, tok/s	106	84
Context	1M	1M
Weights	Closed	Closed
Released	Sep 2026	Oct 2026
See images	✓	✓
Read PDFs	✓	✓
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 → Gemini 4 Argon

Synchronous output stops at 65,536›

With background false, output limits above 65,536 tokens return HTTP 400; stay at or below that limit.

Sampling parameters are ignored›

temperature, top_p and top_k are ignored; remove them from requests.

No explicit caching›

Explicit caching is unavailable; omit explicit cache requests.

Gemini 4 Argon → Sonnet 5.5

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.