Gemini 4 Argon vs Claude Opus 5.5: which fits your task?
Compare Gemini 4 Argon and Claude Opus 5.5 using official context limits, thinking controls, benchmarks and native API differences before choosing a model.
Read as MarkdownGemini 4 Argon vs Claude Opus 5.5 is a choice about input, task and integration. Argon accepts native audio and video alongside text, images and PDFs. Opus offers a familiar Messages contract for applications already built around Claude. Both have million-token context windows and always-on thinking, but those similarities hide different output limits and controls.
This comparison uses official specifications and attributed benchmark results checked on October 14, 2026. We have not run a head-to-head evaluation. Use it to narrow your shortlist, then test the tasks you actually need to complete.
Gemini 4 Argon vs Claude Opus 5.5 specifications
| Decision point | Gemini 4 Argon | Claude Opus 5.5 |
|---|---|---|
| Model ID | gemini-4-argon | claude-opus-5-5 |
| Context | 1,048,576 tokens shared by input, thinking and output | 1M tokens |
| Input | Text, images, audio, video and PDFs | Text and images; PDF documents supported |
| Output | Text | Text |
| Thinking control | low, medium, high | low, medium, high, xhigh, max |
| Default thinking level | medium | medium |
These are official capabilities, not a claim that every operation has been verified through SeedRouter. Read Google's Argon model documentation, Anthropic's Opus 5.5 overview and the effort reference.
Output needs a separate check. Argon can continue a generation across multiple requests, within its remaining shared context. Google's REST guide describes per-request ceilings of 32,768 tokens without streaming and 65,536 with streaming. Those are not the overall long-decode limit. Opus documents a 128K synchronous Messages output limit. Its larger batch beta is a different API offering. See Google's long-decode guide before planning a long response.
Compare current pricing against completed work
Gemini 4 Argon
USD per 1M tokens
| USD per 1M tokens | googlellm | googlellm-vertext |
|---|---|---|
| Input | $0.80 | $1.00 |
| Output, including thinking | $4.00 | $5.00 |
| Cached input | — | — |
Cached tokens are part of input, not additional input. Each continuation request has its own usage. Failed requests are not charged.
Claude Opus 5.5
Claude Opus 5.5 is billed per token. Prices below are USD per 1M tokens for each available group, read live from the current billing configuration.
Model ID: claude-opus-5-5.
| Category | claude | claude-0.7 |
|---|---|---|
| Input | $2.00 | $2.80 |
| Output | $10.00 | $14.00 |
| Cache read | $0.10 | $0.14 |
| Cache write, 5 minutes | $2.50 | $3.50 |
| Cache write, 1 hour | $4.00 | $5.60 |
Total input includes uncached input, cache reads and both cache-write TTLs. When context tiers are shown, the selected tier applies to the whole request. Anthropic reports cache tokens separately from uncached input.
Cost is the sum of each billable token category multiplied by its rate, divided by 1,000,000. Use the rates of the selected group and applicable tier. A request that fails is not charged.
Use these current SeedRouter rates for a budget. Google's introductory Argon pricing ends on November 30, 2026, according to its announcement. That date does not establish future SeedRouter rates.
Token prices alone cannot identify the cheaper model for your task. Thinking consumes output tokens, cache hits affect input charges, and a failed attempt may require another request. Token counts can also differ between models for the same text. Compare the cost of an accepted result, including necessary follow-ups. The Argon pricing guide explains its usage counters; model pricing helps compare the wider shortlist.
What the coding and long-context benchmarks show
Google's Argon model card, printed page 5, reports these two comparisons:
| Benchmark | Argon | Opus 5.5 |
|---|---|---|
| Terminal-Bench 4.0 | 57.4% | 66.4% |
| GraphWalks, 256K–1M tokens, BFS F1 | 84.2% | 66.8% |
The results point in different directions. Opus scores higher on this terminal-agent benchmark; Argon scores higher on this long-context graph traversal task. Neither measures every coding task or every kind of document reasoning.
The evaluation methodology matters: Google computed its Terminal-Bench result and sourced competitors from the leaderboard, while it computed all GraphWalks results. Thinking settings, tools and test harnesses affect interpretation. These published scores help select an experiment; they do not predict your application's pass rate or response time.
Native APIs require different conversation handling
Changing the model name alone does not migrate a native integration.
| Contract | Core request fields | Tool conversation |
|---|---|---|
| Gemini GenerateContent | contents, systemInstruction, generationConfig | functionCall, functionResponse, thoughtSignature |
| Claude Messages | model, messages, max_tokens, system, output_config.effort | tool_use, tool_result, signed thinking blocks |
Keep each model's complete native history. Argon's generationConfig.thinkingConfig.thinkingLevel is distinct from Claude's output_config.effort; identical level names do not imply identical computation. Google Interactions is also a separate contract: its input and previous_interaction_id fields do not belong in GenerateContent.
Opus 5.5 rejects forced tool selection with tool_choice set to any or a specific tool; use its supported auto or none behavior. Anthropic also binds thinking blocks to the model and conversation that produced them. Check its migration guidance, the Argon API reference and the native streaming tutorial before adapting an application.
Questions before choosing
Is Gemini 4 Argon better than Opus 5.5 for coding?
The cited terminal benchmark favors Opus. That is a reason to include it in a coding evaluation, not proof it wins on your repository. Compare accepted fixes using the same task, tests, tools and spending limit.
Does a million-token context mean a million-token answer?
No. Argon's window is shared with input and thinking, and long output uses continuation. Opus has a separate documented synchronous output limit. Reserve space for the work and answer before filling either context window.
Which should I evaluate first?
Start with Gemini 4 Argon when native audio or video input is central. Start with Claude Opus 5.5 when preserving an existing Claude integration reduces the work needed to evaluate it. For Gemini 4 Argon vs Claude Opus 5.5 on text and coding, compare accepted results and total cost on a small, representative task set before committing.
