MODEL COMPARISON

GPT-5.6VSClaude 5

Compare the current GPT and Claude families by protocol, model lifecycle, tool fit, and the cost of a successful task. There is no permanent winner for every use case.

Side-by-side checklist

Same criteria, task, and limits

Decision point	GPT-5.6	Claude 5
Current official IDs	gpt-5.6-sol / terra / luna	claude-fable-5 / opus-5 / sonnet-5
Vendor request style	Responses API and OpenAI SDK	Anthropic Messages API
Gateway path	OpenAI-compatible /v1	OpenAI-compatible route or Claude-specific console config
Published context	1.05M for the three GPT-5.6 tiers	Confirm exact Claude route and platform
Published vendor price	$0.20–$4 input; $1.20–$20 output / 1M	Check current Anthropic pricing and LLMFly route
First test	Structured output and tool schema	Long code/document task and tool loop

GPT-5.6

Run one decision test, not a demo prompt

Use 20–50 representative application cases.
Set pass conditions before seeing model output.
Keep system instructions, tools and output limits equivalent.
Record retries, latency, tokens and manual correction.
Compare cost per accepted result.

Claude 5

What should make you switch

Switch only when the second model improves a requirement that matters to the task—quality, latency, modality, context, tool reliability, or cost per successful task. A newer model name alone is not a migration reason.

Frequently asked questions

Does this page name an overall winner?

No. The table narrows the first test. Your application evaluation determines the result.

Can vendor prices be used as the LLMFly AI bill?

No. Use Model Plaza and a real usage record for platform charges.

How often should the comparison be rerun?

Rerun it when a model version, route price, prompt, tool schema or workload changes materially.

Compare two models available to your API key

Copy both model IDs from Model Plaza before running the evaluation set.

Open Model Plaza