Claude Opus 5 (Adaptive Reasoning, High Effort) vs GPT-5.6 Sol (xhigh): The Ultimate Performance & Pricing Comparison

GPT-5.6 Sol is the stronger default for coding-heavy agents, while Claude Opus 5 offers lower blended cost and a higher general intelligence index.

The supplied scorecard gives GPT-5.6 Sol a coding index of 78.3 versus Claude Opus 5 at 76.5, plus median output of 73.479 versus 54.599 tokens per second. Claude Opus 5 leads the intelligence index at 58.9 versus 57.7 and costs $10 versus $11.25 per 1M blended tokens. Data provided by https://artificialanalysis.ai/

Anthropic positions Claude Opus 5 around complex agentic coding and enterprise work, while OpenAI presents GPT-5.6 Sol as a flagship model for complex reasoning, programming, and professional work. Anthropic's announcement OpenAI's announcement

The practical choice depends on whether your application values coding throughput, broad reasoning quality, lower output cost, or a larger built-in tool surface. The available evidence supports a clear coding and speed preference for GPT-5.6 Sol, but it does not establish a universal winner for every production workload.

Claude Opus 5 is the better value for broad reasoning workflows, while GPT-5.6 Sol is the better fit for coding throughput and tool-rich execution.

Claude Opus 5 uses claude-opus-5 as its official API ID, while claude-opus-5-high is a site slug rather than the API identifier. Anthropic's model overview Anthropic's model ID guide

GPT-5.6 Sol uses gpt-5.6-sol as its fixed model ID, and gpt-5.6 as its stable alias. The xhigh label describes reasoning effort, not a separate model. GPT-5.6 Sol model page OpenAI reasoning guide

Claude Opus 5 is attractive for teams that need provider flexibility and adaptive reasoning. GPT-5.6 Sol is attractive for teams that want a Responses API workflow with function calling, structured outputs, web search, file search, code execution, hosted shell, computer use, MCP, apply patch, and skills. Anthropic's model overview GPT-5.6 Sol model page

The official catalogs currently present both models as available. That reduces immediate migration concern, but stable identifiers still matter for reproducibility, evaluation, and rollback planning. Anthropic's model overview OpenAI's model directory

GPT-5.6 Sol is faster and slightly stronger on the coding index, while Claude Opus 5 scores higher on the broader intelligence index.

GPT-5.6 Sol reaches a coding index of 78.3 versus Claude Opus 5 at 76.5. Its median output speed is 73.479 tokens per second versus 54.599 for Claude Opus 5, while the reported latency is 0.3 seconds for each model. Data provided by https://artificialanalysis.ai/

The speed difference matters most inside agent loops. A model that generates output faster can reduce the time spent waiting between tool calls, patches, test runs, and review steps. Equal reported latency means the advantage is mainly generation throughput, not necessarily a faster first response. That distinction matters for interactive coding assistants and long-running autonomous tasks.

GPT-5.6 Sol also offers a broad Responses API tool surface, including structured outputs, code execution, hosted shell, computer use, MCP, and apply patch. Those capabilities make it easier to build a single agent workflow around planning, execution, and repository changes. GPT-5.6 Sol model page

Claude Opus 5 takes a different route. Adaptive thinking is enabled by default, and effort controls can change how much reasoning the model applies. That behavior may suit difficult research, planning, and open-ended reasoning tasks, but effort is not a strict token budget. Claude Opus 5 update notes Anthropic effort guide

Official benchmark messaging does not close the comparison. Anthropic claims leading results across several agentic and professional evaluations, while OpenAI publishes its own benchmark set under its own testing conditions. The announcements do not provide a directly matched, independently reproduced comparison for these exact workloads. Anthropic's announcement OpenAI's announcement

The evidence gap is important: no supplied source establishes coding success rate, correction rate, or production reliability across a shared test set. Developers should treat the coding index as a useful directional signal, not a complete forecast of accepted patches.

Claude Opus 5 is cheaper under the supplied blended workload, while GPT-5.6 Sol can justify its premium when faster output reduces operator time.

The supplied comparison prices Claude Opus 5 at $10 versus GPT-5.6 Sol at $11.25 per 1M blended tokens. Input pricing is $5 for each model, while output pricing is $25 for Claude Opus 5 and $30 for GPT-5.6 Sol. Data provided by https://artificialanalysis.ai/

The blended figure is useful for ranking the models, but it is not a universal application bill. Output-heavy agents will feel the output price difference more strongly than retrieval-heavy applications. A workflow with repeated tool calls, long reasoning traces, retries, or human review can make a nominally cheaper model more expensive per accepted result.

Anthropic's official pricing also supports prompt caching and a Fast mode, while OpenAI exposes Standard, Batch, Flex, and Fast pricing paths. These options can change the preferred provider after traffic shape, service requirements, and cache behavior are included. Anthropic pricing Claude Opus 5 update notes OpenAI pricing

Reasoning configuration adds another cost variable. Claude's adaptive thinking consumes part of the output allowance, and GPT-5.6 Sol's xhigh setting increases reasoning time and token use. GPT documentation also warns that a low output limit can produce an incomplete response after input and reasoning tokens have already incurred charges. Anthropic thinking guide OpenAI reasoning guide

Community reports reinforce the need to measure accepted work rather than raw token price. Developers have described Claude Opus 5 as overly verbose and prone to overthinking, while GPT-5.6 Sol discussions include conflicting reports of high quality and over-engineered output. Neither discussion provides a reproducible cost-per-successful-task measurement. Claude community discussion GPT-5.6 community discussion

The supplied evidence cannot show whether retries, review time, or failed tool calls reverse the blended-price ranking. Measure cost per accepted patch, completed workflow, or resolved support case before making a final procurement decision.

GPT-5.6 Sol is the stronger first choice for autonomous coding agents, while Claude Opus 5 is the stronger value choice for general reasoning.

Choose GPT-5.6 Sol when the primary workload is repository modification, tool orchestration, or fast generation inside an agent loop. Its coding index is 78.3 versus 76.5 for Claude Opus 5, and its median output speed is 73.479 versus 54.599 tokens per second. The Responses API also exposes a broad set of tools for structured execution and computer-oriented workflows. Data provided by https://artificialanalysis.ai/ GPT-5.6 Sol model page

Choose Claude Opus 5 when general reasoning quality, lower blended cost, or provider portability matters more than coding throughput. Claude Opus 5 leads the supplied intelligence index at 58.9 versus 57.7 and costs $10 versus $11.25 per 1M blended tokens. Anthropic also documents access through the Claude API, Amazon Bedrock, Google Cloud, and Microsoft Foundry. Data provided by https://artificialanalysis.ai/ Anthropic's model overview

Treat reasoning settings as part of the product design. Claude defaults to adaptive thinking, while GPT-5.6 Sol requires deliberate reasoning configuration when using xhigh. Strict tool protocols should be tested with the selected settings because Anthropic documents tool-call formatting risks when thinking is disabled, and OpenAI documents incomplete responses when output limits are too low. Claude Opus 5 update notes Anthropic thinking guide OpenAI reasoning guide

Community evidence does not resolve the final decision. Claude reports emphasize verbosity, overthinking, and unsolicited changes, while GPT reports range from reliable execution to over-engineering and excessive code generation. The testing methods are not controlled, so neither report should define a production policy. Claude community discussion GPT-5.6 community discussion

The safest rollout is a shared acceptance suite covering patch correctness, tool-call validity, review burden, latency, and cost per accepted result. The supplied research does not provide those production measurements, so model selection should remain workload-specific.

Claude Opus 5 and GPT-5.6 Sol need different interpretation of their labels before developers compare API behavior.

Claude Opus 5 is the official model, claude-opus-5 is its API ID and stable alias, and claude-opus-5-high is a site slug. GPT-5.6 Sol is the official model, gpt-5.6-sol is the fixed ID, gpt-5.6 is the stable alias, and xhigh is a reasoning setting. Anthropic's model ID guide GPT-5.6 Sol model page OpenAI reasoning guide

The official materials establish strong capabilities and clear pricing, but they do not answer average production success rate, correction burden, or user experience distribution. Those questions require a controlled evaluation on the developer's own tasks.