Claude Mythos 5 wins on coding (98 vs 90) and writing quality and context window (1M vs 272K). GPT-5.4 wins on price ($2.5 vs $10/1M input). For most workflows, Claude Mythos 5 is the stronger default — superseded by mythos 5.1 — same model as fable 5, safeguards lifted, partner-only.
The safest Claude Mythos 5 vs GPT-5.4 default, the cheaper option worth trying first, and the specialist pick — before you read the detail below.
Claude Mythos 5 is the strongest answer here for Claude Mythos 5 vs GPT-5.4 — pick it when quality of output matters more than the $10.00/1M/1M input you pay for it.
GPT-5.4 handles the same job for about 71% less per token. Start here and only move up if the output is not good enough.
GPT-5.4 is the fastest of these for Claude Mythos 5 vs GPT-5.4 — worth it when latency is what the reader notices, not the last few points of reasoning depth.
Claude Mythos 5 leads on coding with a score of 98 vs 90 for GPT-5.4.
Claude Mythos 5 has the larger context window: 1M vs 272K for GPT-5.4.
GPT-5.4 is cheaper at $2.5/1M input tokens vs $10/1M for Claude Mythos 5.
Go with Claude Mythos 5 if you want one model to handle coding and research — it targets frontier cybersecurity research, autonomous vulnerability discovery, and the absolute capability ceiling.
Choose GPT-5.4 when your work is mostly agentic workflows and desktop automation — that is the workload it was tuned for.
GPT-5.4 is the more cost-efficient option at $2.5/1M input — Claude Mythos 5 costs 4x more per input token, so the gap is worth taking seriously wherever token volume rather than peak quality drives the bill.
Switch the scoring lens to see whether the Claude Mythos 5 vs GPT-5.4 answer changes when cost, speed, or long-document depth leads the decision.
Anthropic / Premium / Sep 1, 2026
Superseded by Mythos 5.1 — same model as Fable 5, safeguards lifted, partner-only.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
You don't have vetted-partner access or don't need lifted safeguards — Fable 5 is the same model, generally available, at the same price.
Where the Claude Mythos 5 vs GPT-5.4 recommendation shifts once you weigh price or latency differently.
Superseded by Mythos 5.1 — same model as Fable 5, safeguards lifted, partner-only.
Best for agentic automation and desktop control workflows.
List prices and published scores — the numbers this page's pick is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| Claude Mythos 5Anthropic | $10.00/1M | $50.00/1M | $200 | 1M tokens | Deliberate | 98 | 97 | 99 |
| GPT-5.4OpenAI | $2.50/1M | $15.00/1M | $55 | 272k tokens | Balanced | 90 | 88 | 88 |
Scores out of 100 — how we evaluate models. “Est. month” is 10M in / 2M out at list price: a ceiling, no discounts.
Why each one is on the shortlist for Claude Mythos 5 vs GPT-5.4, what it is genuinely good at, and where we would steer you away from it.
Ranked first here for Claude Mythos 5 vs GPT-5.4: 98/100 on coding, with the widest margin of anything in this line-up.
Anthropic's most powerful frontier model — the same underlying model as Fable 5 with safeguards lifted in some areas, restricted to vetted enterprise and research partners. The capability ceiling of mid-2026.
You don't have vetted-partner access or don't need lifted safeguards — Fable 5 is the same model, generally available, at the same price.
The most capable model Anthropic has ever shipped — but access is gated to vetted partners because its safeguards are lifted in high-risk areas. For everyone else, Fable 5 is the same model at the same price with standard safety controls. Choose Mythos 5 only if you have partner access and need its security ceiling.
Full pricing, benchmark table and release notes on the Claude Mythos 5 page.
The value option for Claude Mythos 5 vs GPT-5.4: about 71% less per token than Claude Mythos 5, at 90/100 on coding. Worth starting here and moving up only if the output disappoints.
OpenAI's March 2026 flagship with desktop-control capabilities — it can see your screen, click, and navigate apps via the API. Since followed by GPT-5.5, the GPT-5.6 family and GPT-6.
You need the highest current coding benchmark scores — Claude Opus 4.7 and GPT-5.5 are newer premium picks.
Still capable for desktop automation at its $2.50/$15 price, but superseded: GPT-6.1 Sol is stronger at $2/$10, and Claude Opus 5.5 leads coding.
Full pricing, benchmark table and release notes on the GPT-5.4 page.
UseRightAI recommendations are based on practical decision factors people actually feel in day-to-day use.
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Claude Mythos 5 wins on more of the categories we score — coding, research, long context — so it is the better default of the two. GPT-5.4 is the better pick when your work is mostly agentic workflows and desktop automation. Neither is universally "better": Claude Mythos 5 is aimed at frontier cybersecurity research and autonomous vulnerability discovery, GPT-5.4 at agentic workflows and desktop automation.
GPT-5.4 is cheaper at $2.5/1M input and $15/1M output. Claude Mythos 5 costs $10/1M input and $50/1M output.
Claude Mythos 5 has the larger context window at 1M tokens vs GPT-5.4's 272K. For large document analysis, Claude Mythos 5 is the stronger pick.
Claude Mythos 5 is better for coding with a score of 98 vs GPT-5.4's 90 (out of 100). Claude Opus 5.5 is the overall coding leader in this directory at 100/100.
GPT-5.4 is faster with a balanced speed rating (score: 3) vs Claude Mythos 5's deliberate rating (score: 2). Speed matters most for interactive and high-throughput work; for batch jobs the Claude Mythos 5 latency penalty is usually invisible.
Not generally available — limited to vetted partners after Project Glasswing's private preview. Most teams should use Fable 5, which is the same model with standard safeguards. Premium $10/$50 pricing and a deliberate, high-latency profile. Avoid it if you don't have vetted-partner access or don't need lifted safeguards — Fable 5 is the same model, generally available, at the same price. That is the main case for looking at GPT-5.4 instead.
Newer models — Claude Opus 5.5, GPT-6.1 Sol — outperform it on coding benchmarks. Smaller context window (272K) than current 1M-token models. Avoid it if you are starting new work — GPT-6.1 Sol is cheaper and stronger, and Claude Opus 5.5 leads coding. Against Claude Mythos 5 specifically, the gap shows up most on coding (98 vs 90).
Take a moderate workload of 10M input and 2M output tokens a month. Claude Mythos 5 runs $200.00 (at $10/1M in and $50/1M out); GPT-5.4 runs $55.00 (at $2.5/1M in and $15/1M out). That is a $145.00/month difference — GPT-5.4 is the cheaper of the two at this volume, and the gap scales linearly as you send more. Output tokens dominate the bill on both, so prompt length matters far less than response length.
Yes, and for most teams that beats picking one. A common split is Claude Mythos 5 for frontier cybersecurity research and autonomous vulnerability discovery, with GPT-5.4 handling agentic workflows and desktop automation. Routing high-volume, low-stakes calls to GPT-5.4 at $2.5/1M and reserving Claude Mythos 5 for the hard cases is usually the cheapest arrangement that does not cost you quality.