Claude Fable 5 vs gpt-oss-120b
Head-to-head specifications
| Metric | Claude Fable 5 | gpt-oss-120b | Difference |
|---|---|---|---|
| Intelligence Index | 60.0 | 28.0 | +114.3% |
| Coding Index | 76.5 | 30.4 | +151.6% |
| Agentic Index | 52.8 | 13.2 | — |
| Context window | 1M tokens | 256K tokens | — |
| Blended price ($/1M tokens) | $1.68 | $0.20 | +740.0% |
| Output speed (tokens/s) | 65 | 272 | -76.1% |
| Access | Proprietary API | Open weights | — |
- Claude Fable 5 leads overall capability (Intelligence Index 60.0 vs 28.0).
- gpt-oss-120b is the cheaper model to run at $0.20/1M blended tokens — about 8.4× cheaper.
- Claude Fable 5 offers the larger context window (1M tokens), useful for long documents and codebases.
Verdict: Claude Fable 5 or gpt-oss-120b?
Claude Fable 5 advantages
- General intelligence (+53%)
- Coding ability (+60%)
- Agentic task performance (+75%)
- Context window (+74%)
gpt-oss-120b advantages
- Affordability (+88%)
- Output speed (+76%)
Which should you choose?
- Choose the Claude Fable 5 if you need the strongest overall reasoning and accuracy.
- Choose the gpt-oss-120b if you want the lowest cost per token at scale.
- Choose the Claude Fable 5 if coding and software development are your main workload.
Value for money
gpt-oss-120b offers more intelligence per dollar (3.9× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use. It is also open-weight, so self-hosting can reduce costs further at scale.
Claude Fable 5 vs gpt-oss-120b: which should you choose?
Claude Fable 5 — Anthropic multimodal model with an Intelligence Index of 60, a 1M-token context window and a blended price of $1.68/1M tokens.
gpt-oss-120b — OpenAI text model with an Intelligence Index of 28, a 256K-token context window and a blended price of $0.2/1M tokens (open weights).
Claude Fable 5 vs gpt-oss-120b: Claude Fable 5 scores higher on the Intelligence Index. Claude Fable 5 leads overall capability (Intelligence Index 60.0 vs 28.0). gpt-oss-120b is the cheaper model to run at $0.20/1M blended tokens — about 8.4× cheaper.
Capability: intelligence, coding and agentic work
On the composite Intelligence Index the Claude Fable 5 scores 60.0 versus 28.0. For software development, the Coding Index puts Claude Fable 5 ahead (76.5 vs 30.4). On agentic, multi-step tool-use tasks, Claude Fable 5 measures stronger. Composite indices summarize many evaluations, but always test on your own workload before committing.
Context window and speed
The Claude Fable 5 accepts up to 1 million tokens per request, which sets how much documentation, transcript or code it can reason over at once. In measured throughput, gpt-oss-120b generates faster (272 vs 65 tokens/s), which matters for interactive apps and high-volume pipelines.
Pricing and access
At blended per-token rates, gpt-oss-120b is the cheaper model to run ($0.20 vs $1.68 per 1M tokens). Claude Fable 5 is proprietary api and gpt-oss-120b is open weights. Open-weight models can be self-hosted, trading per-call cost for infrastructure you manage; for production also weigh rate limits, throughput and data-residency requirements.
The verdict
Both are credible choices in the ai model comparison space; the specification table above lays out every metric so you can weigh the trade-offs that matter to you. Pick the one whose strengths line up with how you will actually use it.
Frequently asked questions
Is the Claude Fable 5 better than the gpt-oss-120b?
Claude Fable 5 takes the overall edge, though gpt-oss-120b wins in specific areas worth weighing. Claude Fable 5 leads overall capability (Intelligence Index 60.0 vs 28.0).
What is the main difference between the Claude Fable 5 and the gpt-oss-120b?
Claude Fable 5 leads overall capability (Intelligence Index 60.0 vs 28.0). gpt-oss-120b is the cheaper model to run at $0.20/1M blended tokens — about 8.4× cheaper.
Which is better value?
gpt-oss-120b offers more intelligence per dollar (3.9× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use. It is also open-weight, so self-hosting can reduce costs further at scale.
Which should I choose?
Choose the Claude Fable 5 if you need the strongest overall reasoning and accuracy. Choose the gpt-oss-120b if you want the lowest cost per token at scale.
Methodology
Large language models are compared on independent leaderboard metrics: an Intelligence Index (a composite of reasoning and knowledge evaluations), Coding and Agentic indices where measured, community arena Elo, maximum context window, a blended API price per million tokens (weighted across cache-hit, input and output rates), and measured output speed in tokens per second. Where a model ships multiple reasoning-effort variants, we report its strongest variant. Benchmarks capture only part of real-world quality, which also depends on tool use, latency, safety and task fit — and this space moves quickly, so figures reflect the leaderboard snapshot on the page date.