Claude Opus 5
Claude Opus 5 is a flagship candidate for high-complexity text work. Kyeo AI limits each message to 20,000 characters, includes the 40 most recent submitted messages, and caps output at 4,096 tokens.
At a glance
What is this model like?
Before creation, the site reserves against a conservative input bound for the complete message history plus the maximum output. A successful response settles against reported actual credits. The model does not accept attachments, and visual or tool capabilities available through other Claude products are not treated as features here.
Key facts
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Also known as
The same model may appear under different names across documentation and community discussions; this list keeps them easy to search and compare.
Common questions
These practical questions focus on the task, input conditions, and result requirements you should confirm before choosing.
Selection guide
Use these decision points when choosing a model.
Use a representative sample to compare Opus 5 when mistakes would create significant rework or decision cost.
Start with the lower-rate Sonnet 5 and upgrade only when a measurable benefit appears.
Split the work into an outline, sections, and a final review to stay within the output limit.
Popular comparisons
Compare common alternatives on the same task to clarify differences in inputs, controls, and cost.
Model comparison
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Practical usage insights
Practical guidance based on public sources, current on-site limits, and representative tasks.
Flagship selection needs task-level evidence
Settlement evidence is part of production readiness
Capabilities
Constraint reasoning
Critical review
Professional writing
Use cases
Strategy proposals
First-pass review of high-risk documents
Research reports
Prompt tips
Define the evidence boundary
Request an opposing-case review
Start with a short sample
Why choose it
What to know first
Adjustable parameters
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Credit usage
400 credits per million input tokens and 2,000 credits per million output tokens; settlement uses the credits reported by the response.
Before batch generation, run an A/B test with the same assets across the current model and alternatives to validate quality and avoid wasting credits.
FAQ
Related models
Compare these similar candidates before deciding.
Claude Opus 4.8
Claude Opus 4.8 is designed for high-complexity text analysis and consequential writing. Kyeo AI offers text-only chat with up to 20,000 characters per message and an explicit 4,096-token maximum output.
Claude Sonnet 5
Claude Sonnet 5 is the more balanced Claude candidate in this batch for research, code explanation, and structured writing. Its maximum output on this site is 4,096 tokens.
Claude Fable 5
Claude Fable 5 is designed for demanding narrative development and creative collaboration. Kyeo AI offers text-only access with a 4,096-token maximum output and sends no tool or attachment fields.
Sources
Content is based on model documentation, feature references, and the settings available on Kyeo AI.
Claude Opus 5 is integrated through a text-only Messages contract. Requests explicitly set a 4,096-token maximum output, while standard and streaming responses use the same three-way settlement based on reported actual credits.
Records text-only Messages, the 4,096-token maximum output, rates, and actual-credit settlement.