# Claude Fable vs Opus for coding: is the top model worth it?

> Claude Fable vs Opus for coding: Fable 5.1 costs 2.5 times Opus 5.5 per token, and Anthropic says Opus matches it on most work. Fable pays on long runs.

Source: https://shuriken.sh/compare/fable-vs-opus-for-coding

For everyday coding, Opus is the better buy: Claude Fable 5.1 costs 2.5 times as much per token as Claude Opus 5.5, and Anthropic says Opus 5.5 "performs at the level of Claude Fable 5.1 on most work". Fable earns its price on long, unattended runs and the hardest problems.

By Shuriken Updated 27 October 2026 6 min read

**Contents**

We make Shuriken. We tried to be fair; corrections welcome at office@shuriken.sh.

## Quick answer #

For everyday coding, Opus is the better buy. Claude Fable 5.1 costs $10 / $50 per million tokens against $4 / $20 for Claude Opus 5.5, 2.5 times as much, and it starts at high effort where Opus 5.5 starts at medium. On a Max plan it also eats your weekly limit faster. Anthropic itself says Opus 5.5 "performs at the level of Claude Fable 5.1 on most work". Fable earns its price on long, unattended runs and the hardest problems, where Opus at a higher effort still falls short.

Every number on this page comes from Anthropic's own pages as we read them on 22 October 2026. Opus 5.5 shipped three weeks after Fable 5.1, so a price or a default here can be out of date within a month: check the dates.

## At a glance #

US dollars, API list prices per million tokens ("MTok").

| | Claude Fable 5.1 | Claude Opus 5.5 |
| --- | --- | --- |
| Released | [1 September 2026](https://platform.claude.com/docs/en/models/fable-5-1/overview) | [22 September 2026](https://platform.claude.com/docs/en/models/opus-5-5/overview) |
| What Anthropic says it's for | "Demanding reasoning and long-horizon agentic work" | "Long-running agentic coding and knowledge work" |
| Input / output | $10 / $50 | $4 / $20 |
| Cache read | $0.25 | $0.20 |
| Thinking | Adaptive, always on | Adaptive, always on |
| Default effort | high | medium |
| Latency ([Anthropic's label](https://platform.claude.com/docs/en/models/overview)) | Slower | Moderate |
| Context window / max output | 1M / 128K tokens | 1M / 128K tokens |
| Default model in Claude Code | Never: you pick it | Yes, on Pro, Max, Team, Enterprise and the API |
| On Claude Pro | Usage credits only | Included in your limits |
| On Claude Max | Included, up to 50% of weekly limits | Included |

The default-effort row is Claude Code's and the API's own default. In Claude Code you can change it per session with /effort.

## What Fable does well #

Anthropic positions Fable as the model for work that is bigger than one sitting. The [Claude Code model docs](https://code.claude.com/docs/en/model-config) describe both Fable models as "suited to tasks larger than a single sitting. They sustain long autonomous sessions, investigate before acting, and verify their work more often than smaller models."

Anthropic's [Fable 5.1 launch page](https://www.anthropic.com/claude-fable-and-mythos-5-1) quotes customers who left it running for hours unattended, with "strong verification loops". The [models overview](https://platform.claude.com/docs/en/models/overview) gives the rule in one line: start with Opus 5.5, and use Fable 5.1 "for demanding reasoning and long-horizon agentic work, or when your evals on Claude Opus 5.5 at higher effort still fall short".

Fable is worth a try when:

- a job runs for hours on its own, like a migration across a large codebase, where a wrong turn early costs more than the tokens;
- Opus has already failed at xhigh or max effort, which is Anthropic's own test and a fair one;
- the problem is hard rather than long: a race condition nobody can reproduce, an outage to debug, or a design decision with many moving parts (the Claude Code docs name root-cause investigations, outage debugging and architecture decisions as Fable work).

## Why Opus is the everyday default #

Anthropic gives three reasons of its own.

- It's close on quality. In the [Opus 5.5 announcement](https://www.anthropic.com/claude-opus-5-5), Anthropic reports 52.5% on CursorBench for Opus 5.5 at its default (medium) effort, against 51.8% for Fable 5.1 at max effort. In one long coding test on that page, Opus 5.5 "finished in 9.5 hours compared to 12 for Fable 5.1, and cost 51% less."
- It's faster. Anthropic labels Fable "Slower" and Opus "Moderate", and in a chat you're watching the difference is waiting time.
- It's the default. Claude Code's docs say Opus 5.5 is the default on Pro, Max, Team, Enterprise and the API, and that "Fable models are not the account-type default on any plan or provider."

All three scores are Anthropic's, measured on Anthropic's tasks, and your repository isn't one of them. [Fable 5.1 vs Opus 5.5](https://shuriken.sh/compare/models/claude-fable-5-1-vs-claude-opus-5-5) lists each score with its source, next to our session costs for both models.

Shuriken shows what every plan you hold has left in one figure, and what each turn costs as it runs.

[Download](https://shuriken.sh/download)

## Price per token and per task #

Fable 5.1 costs 2.5 times Opus 5.5 on input ($10 against $4) and on output ($50 against $20). Cache reads are closer, $0.25 against $0.20, because Fable 5.1's cache reads cost [2.5% of its input price](https://platform.claude.com/docs/en/about-claude/pricing) and Opus 5.5's cost 5%.

Per task, the gap is usually wider, for two reasons:

- Thinking is billed as output. Both models always think, and output is the expensive side. Fable defaults to high effort and Opus 5.5 to medium, so a Fable turn tends to write more thinking tokens for the same request.
- Long runs re-read a lot of context. An agent sends its whole conversation on every request (the mechanics are in [why Claude Code uses so many tokens](https://shuriken.sh/guides/why-claude-code-burns-tokens)). Most of that is cache reads, where the two are close; the new input and the output are where Fable costs 2.5 times as much.

Take one request at list prices: 100,000 tokens of context, 90,000 of them from cache, and 5,000 tokens written, thinking included. Cache writes are left out to keep it short.

| One request | Opus 5.5 | Fable 5.1 |
| --- | --- | --- |
| 10,000 new input tokens | $0.04 | $0.10 |
| 90,000 cache-read tokens | $0.018 | $0.0225 |
| 5,000 output tokens | $0.10 | $0.25 |
| Total | about $0.16 | about $0.37 |

We worked that out from the price list; nobody measured it. With the same work and the same token counts, Fable comes to about 2.4 times as much. If its high default makes it write more, the gap grows, and if it finishes in fewer requests, the gap shrinks. Anthropic's long test went the other way again: Opus finished first and cost 51% less.

## How plan limits treat each #

On a subscription, the plan decides more than the price list does. Anthropic's help page [Claude Fable models on your plan](https://support.claude.com/en/articles/15424964-claude-fable-models-on-your-plan) splits it like this:

- Free: no Fable.
- Pro, and standard Team seats: Fable models "aren't included in your plan's usage limits". They run on pay-as-you-go usage credits from the first request. Claude Code's [model docs](https://code.claude.com/docs/en/model-config) add that an interactive session asks you to confirm before a Fable request bills usage credits, and the /model picker marks the Fable row "Requires usage credits". With claude -p there is no prompt, and the credits are billed without asking.
- Max, and premium Team seats: included. "You can use up to 50% of your weekly usage limits on Fable models at no extra cost." Fable draws from your regular weekly limits and uses them "faster than other Claude models".
- Usage-based Enterprise and the API: standard API rates.

So on Max, a Fable-heavy Monday can leave you with less week than you planned. [Max 5x vs Max 20x](https://shuriken.sh/guides/claude-max-vs-max-20x) sets out how much room each tier gives.

## Using them together #

You don't have to choose once. In Claude Code:

- Switch per job: /model fable for the long, hard one, /model opus for the rest. claude --model fable starts a session on it, and Fable 5.1 needs Claude Code v2.1.257 or later.
- Know what the helpers run on. A switch with /model also reaches subagents that inherit the session's model, while a custom subagent with its own model line keeps that one ([subagent docs](https://code.claude.com/docs/en/sub-agents)). With a Claude subscription, the built-in Explore subagent runs on Opus while your session is on Fable.
- Set the effort per job. Fable supports low to max with /effort.

If you keep a Pro plan for daily work and a Max plan for heavy weeks, Shuriken can put both in one place and move a chat to the account with the most room when the one in use reaches your switch point (99% by default). A Fable chat that hits "needs usage credits" or its Fable limit moves to another of your accounts with Fable room; if none has any, it carries on with Opus 5.5, and the chat shows a card such as "Switched to Opus 5.5 · Fable 5.1 needs usage credits". Only add accounts you own and are entitled to use; providers' terms may not allow sharing a subscription sign-in. Our [Pro vs Max guide](https://shuriken.sh/guides/claude-pro-vs-max-for-claude-code) helps size the plans first, and [source switching](https://shuriken.sh/features/source-switching) explains the moves.

Try the free tool: [Claude limit reset tracker](https://shuriken.sh/tools/limit-resets/claude)

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## Sources

- [Models overview (Claude API docs)](https://platform.claude.com/docs/en/models/overview) (accessed 22 October 2026)
- [Claude Fable 5.1 (Claude API docs)](https://platform.claude.com/docs/en/models/fable-5-1/overview) (accessed 22 October 2026)
- [Claude Opus 5.5 (Claude API docs)](https://platform.claude.com/docs/en/models/opus-5-5/overview) (accessed 22 October 2026)
- [Pricing (Claude API docs)](https://platform.claude.com/docs/en/about-claude/pricing) (accessed 22 October 2026)
- [Introducing Claude Opus 5.5 (Anthropic)](https://www.anthropic.com/claude-opus-5-5) (accessed 22 October 2026)
- [Claude Fable 5.1 and Mythos 5.1 (Anthropic)](https://www.anthropic.com/claude-fable-and-mythos-5-1) (accessed 22 October 2026)
- [Claude Fable models on your plan (Claude Help Center)](https://support.claude.com/en/articles/15424964-claude-fable-models-on-your-plan) (accessed 22 October 2026)
- [Model configuration (Claude Code docs)](https://code.claude.com/docs/en/model-config) (accessed 22 October 2026)
- [Create custom subagents (Claude Code docs)](https://code.claude.com/docs/en/sub-agents) (accessed 22 October 2026)

## Frequently asked questions

**Is Claude Fable better than Opus for coding?**

Not on most everyday work. Anthropic says Opus 5.5 performs at the level of Fable 5.1 on most work, at a lower price. Fable 5.1 is meant for demanding reasoning and long-horizon agentic work, or for jobs where Opus at a higher effort still falls short.

**How much more does Fable cost than Opus?**

As of 22 October 2026, Fable 5.1 costs $10 per million input tokens and $50 per million output tokens on the API. Opus 5.5 costs $4 and $20. That is 2.5 times the price per token, before Fable's higher default effort adds thinking tokens.

**Can I use Fable on the Claude Pro plan?**

Yes, but not from your plan's limits. Anthropic's help page says Fable models run on pay-as-you-go usage credits on Pro and on standard Team seats. On Max and premium Team seats they are included, up to 50% of your weekly limits.

**How do I switch Claude Code to Fable?**

Run /model fable in a session, or start one with claude --model fable. Neither Fable model is the default on any plan, so Claude Code stays on Opus 5.5 until you pick it.

**Does Fable use my Max limits faster?**

Yes. Anthropic says Fable models draw from your plan's regular weekly limits and use them faster than other Claude models, and you can spend at most half of your weekly limits on them.

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Shuriken adds up what your subscriptions have left, one figure per provider and per limit, in the top bar.

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## Keep reading

- [Opus vs Sonnet for coding: which Claude model to use: Guide 27 Oct 2026 6 min read Opus vs Sonnet for coding: Sonnet 5.5 for well-scoped work, Opus 5.5 for long or open-ended jobs. Opus costs twice as much per token; judge it per task.](https://shuriken.sh/guides/opus-vs-sonnet-for-coding)
- [Claude's weekly limit, explained: Guide 27 Oct 2026 6 min read Paid Claude plans have a weekly limit on top of the 5-hour window. When it resets, how model limits fit in, and why parallel agents reach it in two days.](https://shuriken.sh/guides/claude-weekly-limit-explained)
- [Amp vs Claude Code: pricing, models and fit: Comparison 27 Oct 2026 9 min read Amp is free to start and bills models at API prices with no markup; Claude Code runs Claude models on a flat Pro or Max plan. Prices and terms compared.](https://shuriken.sh/compare/amp-vs-claude-code)
- [Best AI coding subscription in 2026, by how you work: Comparison 27 Oct 2026 5 min read The best AI coding subscription in 2026 depends on how you work. Claude, ChatGPT, Google, Cursor and Copilot plans compared: price, limits, who each suits.](https://shuriken.sh/compare/best-ai-coding-subscription)
- [ChatGPT Plus vs Claude Pro for coding: the $20 plans: Comparison 27 Oct 2026 7 min read ChatGPT Plus and Claude Pro both cost $20 and include a coding agent, Codex or Claude Code. Their limits, models and extras, from each vendor's own pages.](https://shuriken.sh/compare/chatgpt-plus-vs-claude-pro-for-coding)
- [Claude Max vs ChatGPT Pro for coding (2026): Comparison 27 Oct 2026 6 min read Claude Max vs ChatGPT Pro for coding: both start at $100 a month. Max has a five-hour window plus a weekly limit; Pro has no five-hour limit for now.](https://shuriken.sh/compare/claude-max-vs-chatgpt-pro-for-coding)

## Free tools

- [Claude limit reset tracker](https://shuriken.sh/tools/limit-resets/claude)
- [Codex limit reset tracker](https://shuriken.sh/tools/limit-resets/codex)