Reasonix vs. Claude Code vs. DeepSeek TUI: Three Coding Agents, One Task, Three Very Different Bills

Three Terminal Agents, One Question: How Much Per Day?

All three tools are CLI-based AI coding agents that read your codebase, write code, and execute commands. But they use fundamentally different models and pricing structures, which means the same day of work produces wildly different bills. Here's the breakdown.

The Three Agents

• DeepSeek Reasonix — Open-source CLI agent (npm: reasonix) built specifically for DeepSeek's API. Engineered for maximum prefix cache hit rates. Uses DeepSeek V4 Flash.
• Claude Code — Anthropic's official CLI agent. Uses Claude Opus 4.7/4.8 (default) or Sonnet 4.6. API-billed per token with prompt caching.
• DeepSeek TUI — A community terminal UI for DeepSeek models. Standard DeepSeek API integration without specialized cache optimization. Uses DeepSeek V4 Flash or V4 Pro.

Model Pricing Reference

Scenario: A Full Day of Feature Development

We model a realistic day: 6 hours of active AI-assisted coding, building a medium-complexity feature (API endpoints, database schema, frontend components, tests). Approximately 150M input tokens processed and 3M output tokens generated across the full session.

Cost Breakdown: Same Workload, Three Bills

With Claude Code on Opus (Heavy Usage)

If you use Claude Code with Opus 4.8 (the default for complex tasks), the numbers escalate further:

• Input cost (150M tokens, 70% cached): 45M × $15/M + 105M × $3.75/M = $675 + $394 = ~$1,069/day
• Output cost (3M tokens): 3M × $75/M = $225/day
• Total: ~$1,294/day or ~$28,000/month

This is why most Claude Code users limit their sessions or use Sonnet for routine tasks and reserve Opus for complex reasoning.

Why the Gap Is So Large

The 100×–1000× cost difference comes from two compounding factors:

• Model pricing tier: Claude Opus output costs $75/M vs. DeepSeek V4 Flash at $0.28/M — a 268× base price gap. Even Sonnet at $15/M is 54× more expensive for output.
• Cache efficiency: Reasonix achieves 99% cache hits via engineered prompt stability. Claude Code achieves ~70% with standard prompt caching. DeepSeek TUI without optimization gets 40–60%. On DeepSeek's pricing, cache hits are 50× cheaper than misses.

Quality vs. Cost Tradeoff

Cheaper is not automatically better. The price gap reflects real capability differences:

Claude Code's Opus model is widely considered the strongest coding model available. You pay a premium for that capability. For tasks requiring deep architectural reasoning, cross-file dependency tracking, and complex debugging, Opus often solves problems in fewer iterations — which partially offsets the per-token cost advantage of cheaper models.

The Smart Hybrid Approach

Many developers are adopting a tiered strategy:

• Routine coding (70% of tasks): Reasonix or DeepSeek TUI — boilerplate, simple features, test writing. Cost: ~$1–$10/day.
• Complex tasks (30% of tasks): Claude Code with Sonnet or Opus — architecture decisions, difficult bugs, multi-system refactors. Cost: ~$20–$100/day for those sessions.

This blended approach yields a monthly cost of roughly $150–$500 depending on how often you need frontier reasoning — far less than using Claude Code exclusively, but with access to its capabilities when you need them.

Bottom Line

If cost is the primary constraint and your tasks are standard development work, Reasonix is unbeatable at ~$28/month for heavy daily use. If you need the most capable reasoning model and money is not the primary concern, Claude Code with Opus delivers the highest quality output. DeepSeek TUI sits in the middle — same model as Reasonix but without the cache optimization, costing roughly 8× more for the same workload.

For a personalized estimate based on your project size and tooling preferences, use the AI Cost Estimator.