LLM Reference

Claude Opus 4.8 vs Gemini 3.1 Flash-Lite

Claude Opus 4.8 (2026) and Gemini 3.1 Flash-Lite (2026) are frontier reasoning models from Anthropic and Google DeepMind. Claude Opus 4.8 ships a 1m-token context window, while Gemini 3.1 Flash-Lite ships a 1.05m-token context window. On Google-Proof Q&A, Claude Opus 4.8 leads by 6.7 pts. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.

Gemini 3.1 Flash-Lite is ~1900% cheaper at $0.25/1M; pay for Claude Opus 4.8 only for coding workflow support.

Decision scorecard

Local evidence first
SignalClaude Opus 4.8Gemini 3.1 Flash-Lite
Best forreasoning-heavy apps, multimodal apps, and tool-calling agentsmultimodal apps, tool-calling agents, and long-context analysis
Decision fitCoding, RAG, and AgentsCoding, RAG, and Agents
Context window1m1.05m
Cheapest output$25/1M tokens$1.50/1M tokens
Provider routes6 tracked3 tracked
Shared benchmarksGoogle-Proof Q&A leader1 shared

Decision tradeoffs

Choose Claude Opus 4.8 when...
  • Claude Opus 4.8 holds a shared-benchmark lead on Google-Proof Q&A, ahead by 6.7 points.
  • Claude Opus 4.8 has broader tracked provider coverage for fallback and route flexibility.
  • Claude Opus 4.8 uniquely exposes Reasoning, Computer use, and Parallel agents in local model data.
  • Local decision data tags Claude Opus 4.8 for Coding, RAG, and Agents.
Choose Gemini 3.1 Flash-Lite when...
  • Gemini 3.1 Flash-Lite has the larger context window for long prompts, retrieval packs, or transcript analysis.
  • Gemini 3.1 Flash-Lite has the lower cheapest tracked output price at $1.50/1M tokens.
  • Local decision data tags Gemini 3.1 Flash-Lite 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.

Lower estimate Gemini 3.1 Flash-Lite

Claude Opus 4.8

$10,250

Cheapest tracked route/tier: Anthropic

Gemini 3.1 Flash-Lite

$575

Cheapest tracked route/tier: Google AI Studio

Estimated monthly gap: $9,675. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.

Switch friction

Claude Opus 4.8 -> Gemini 3.1 Flash-Lite
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • Gemini 3.1 Flash-Lite is $23.50/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
  • Check replacement coverage for Reasoning, Computer use, and Parallel agents before moving production traffic.
Gemini 3.1 Flash-Lite -> Claude Opus 4.8
  • Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
  • Claude Opus 4.8 is $23.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
  • Claude Opus 4.8 adds Reasoning, Computer use, and Parallel agents in local capability data.

Specs

Specification
Released2026-05-282026-05-07
Context window1m1.05m
Parameters——
ArchitectureDecoder OnlyDecoder Only
LicenseProprietaryProprietary
OpennessProprietaryProprietary
WeightsNot releasedNot released
CodeNot releasedUnknown
Commercial useCommercial use: conditionalCommercial use: conditional
Knowledge cutoff2026-012025-01

Pricing and availability

Pricing attributeClaude Opus 4.8Gemini 3.1 Flash-Lite
Input price$5/1M tokens$0.25/1M tokens
Output price$25/1M tokens$1.50/1M tokens
Providers
AnthropicAWS BedrockGCP Vertex AIMicrosoft FoundryOpenRouterVercel AI Gateway
Google AI StudioOpenRouterVercel AI Gateway

Capabilities

CapabilityClaude Opus 4.8Gemini 3.1 Flash-Lite
VisionYesYes
MultimodalYesYes
ReasoningYesNo
JSON / Tool useYesYes
Structured outputsYesYes
Code executionYesYes
IDE integrationNoNo
Computer useYesNo
Parallel agentsYesNo

Benchmarks

BenchmarkClaude Opus 4.8Gemini 3.1 Flash-Lite
Google-Proof Q&A93.686.9

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Model pages
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Last reviewed: 2026-07-26. Data sourced from public model cards and provider documentation.