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Cost per coding-agent request

Is Claude Fable 5.1 or GPT-6 Luna cheaper for coding agents?

For coding agents, Claude Fable 5.1 costs 58x as much as GPT-6 Luna per request ($0.24 vs $0.0041 on our measured traffic), because Claude Fable 5.1 lists at $10 input, $0.25 cached input and $50 output per million tokens against $0.10, $0.01 and $0.50 for GPT-6 Luna, and GPT-6 Luna charges more for prompts over 272K tokens.

List prices: Anthropic pricing, OpenAI API pricing, checked 2026-10-13. Request costs: Standard Compute gateway data, 79,301 coding-agent requests from 75 users, Sep 13 to Oct 12, 2026. How we compute this

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Cost per coding-agent request, side by side

Cost at list priceGPT-6 LunaFable 5.1
Prompt under 100K tokens50% of requests, 87% of input cached$0.0015$0.12
Prompt of 100K to 272K39% of requests, 88% of input cached$0.0039$0.28
Prompt over 272K tokens11% of requests, 86% of input cached$0.017$0.63
Average request$0.0041$0.24
100 requests$0.41$23.76
Median session16 requests; a session ends after 10 idle minutes$0.045$3.26
A month of regular usemedian of 20 users active on 5+ days$5.83$332

Each logged request priced at the vendor’s list rates for its own token counts, including cache reads and any higher rate for long prompts. Average output: 698 tokens per request.

Benchmarks, speed and latency, side by side

Artificial AnalysisGPT-6 LunaFable 5.1
Intelligence Index10 evaluations, 0 to 1003853
Terminal-Bench 4.0agentic coding in a terminal12.6%52.0%
Output speedmedian136 tokens/s71 tokens/s
Time to first answer tokenincludes thinking time101 s4.0 min

Source: Artificial Analysis (artificialanalysis.ai). Measured variants: GPT-6 Luna (Max), speed on OpenAI; Claude Fable 5.1 (Max, Default Fallback), speed on Anthropic. Fetched October 13, 2026. Artificial Analysis runs Terminal-Bench 4.0 in its own setup, so its scores differ from the tbench.ai leaderboard.

What to watch for

Claude Fable 5.1 scores clearly higher on the benchmarks above, so it may finish hard tasks in fewer steps.

FAQ

Is GPT-6 Luna cheaper than Claude Fable 5.1 for coding agents?
Yes, at list prices. 100 average coding-agent requests cost $0.41 on GPT-6 Luna and $23.76 on Claude Fable 5.1. A median 16-request session costs $0.045 vs $3.26. Measured on 79,301 real coding-agent requests (Sep 13 to Oct 12, 2026).
How much does a month of Fable 5.1 vs GPT-6 Luna cost?
For the median regular user in our data (1,478 requests in 30 days), about $332 on Claude Fable 5.1 and $5.83 on GPT-6 Luna at list price. Heavier users pay proportionally more.
Claude Fable 5.1 vs GPT-6 Luna: which is better for agents?
Claude Fable 5.1 scores higher on output quality (9.4/10 vs 7.5/10), while GPT-6 Luna is the cheaper option. Claude Fable 5.1 is best for teams already standardized on Fable that want the newest premium Claude; GPT-6 Luna is best for cheap, fast subtasks, routing and subagents in OpenAI-based stacks. Live community votes on this page show what people actually prefer.
Can I switch between Claude Fable 5.1 and GPT-6 Luna in the same agent?
Yes. Model-agnostic agents (Cline, Aider, OpenClaw, Hermes Agent, Kilo Code, OpenCode, Continue) let you swap models per task. Many people route hard tasks to the stronger model and routine work to the cheaper one.

Community vote

Pick a winner in each dimension. You can change your vote any time.

Output Quality
Correctness and depth of what it produces
Agentic Ability
Tool calls, instruction-following, and multi-step tasks
Speed
Tokens per second and time-to-first-token
Value for money
How much capability you get per dollar
Reliability
Consistent results: fewer refusals, loops and format breaks

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