Anthropic's Claude model for demanding reasoning and long-horizon agentic work, released as the successor to Fable 5.1. It costs less than 5.1 on input, output and cache, at the same context window; Anthropic points most workloads to the cheaper Opus 5.5.
pick it if
Opus 5.5 at higher effort still falls short on your evals
you run Fable 5.1 today and want lower rates on the same window
you run long agent sessions; cache hits bill at 2.5% of input
skip it if
Opus 5.5 covers your workload at half the per-token price
your code forces tool use, prefills replies, sets temperature or edits earlier turns; all return errors
Gemini 4 Argon is Google's flagship reasoning model, built for complex software engineering, with a 1M-token context shared by input and output. its introductory $2 / $10 rate undercuts Gemini 3.1 Pro on output until it doubles to $4 / $20 on 2026-12-01.
pick it if
want Google's flagship reasoning model with low, medium or high thinking
need video, audio or PDF input alongside images in one context
send long prompts: no long-context surcharge and $0.10 cached input
skip it if
you plan heavy volume after 2026-12-01, when rates double to $4 / $20
Gemini 3.8 Flash at $0.75 / $3.75 already covers your workload
faq
which is cheaper, Claude Fable 5.2 or Gemini 4 Argon?
Gemini 4 Argon lists lower input and output prices. on a coding-agent session (2M tokens in, 60,000 out) Claude Fable 5.2 costs $18.40 and Gemini 4 Argon $4.60.
can i switch between Claude Fable 5.2 and Gemini 4 Argon mid-task?
yes. in an octomind session, /model octohub:claude-fable-5-2 and /model octohub:gemini-4-argon switch models without losing the conversation, so you can draft on one and review on the other.
try either model
switch between models inside the same octomind session.