One agent session
1M input tokens and 100K output tokens, no caching.
- Input1M x $10 = $10.00
- Output0.1M x $50 = $5.00
$15.00per session
Anthropic - Closed weights
Claude Fable 5.1 pricing and specs
Claude Fable 5.1 is a closed-weights model from Anthropic that costs $10 per 1M input tokens and $50 per 1M output tokens on the first-party API, with a 1M-token context window.
Last verified from platform.claude.com. All sources
- Input / 1M
- $10
- Output / 1M
- $50
- Context
- 1M tokens
- Weights
- Closed
Pricing per 1M tokens
| Item | Price / 1M tokens |
|---|---|
| Input | $10 |
| Output | $50 |
| Cache read | $0.25 |
| Cache write (5 minutes) | $12.50 |
| Cache write (1 hour) | $20 |
| Batch inputBatch requests | $5 |
| Batch outputBatch requests | $25 |
Note: Cache reads are 0.025x base input on Fable 5.1 (0.1x on most other Claude models).
Specs
- Context window
- 1,000,000 tokens
- Max output
- 128,000 tokens
- Release date
- Provider
- Anthropic
- API model id
claude-fable-5-1- Vercel AI Gateway id
anthropic/claude-fable-5.1- Weights
- Closed weights
What Claude Fable 5.1 costs in practice
Worked from the standard list rates above, with the math shown so you can swap in your own token counts.
A chat app
10,000 requests a day at 2K input and 500 output tokens each.
- Input20M x $10 = $200.00
- Output5M x $50 = $250.00
$450.00per day
$13,500.00 per 30-day month
The same session at a 90% cache hit
90% of the input is read from the prompt cache. The one-time cache write premium is not included.
- Cached input0.9M x $0.25 = $0.225
- Uncached input0.1M x $10 = $1.00
- Output0.1M x $50 = $5.00
$6.23per session
Compare with
| Model | Input / 1M | Output / 1M |
|---|---|---|
| Claude Fable 5.1 (this page) | $10 | $50 |
| Claude Opus 5.5Anthropic | $4 | $20 |
| Claude Sonnet 5.5Anthropic | $2 | $10 |
| GLM-5.3Z.ai | $1.40 | $4.40 |
| Claude Haiku 5.5Anthropic | $0.10 | $0.50 |
Related reading
- Claude Code Idle Compaction: What It Does and How to Turn It OffClaude Code 2.1.299 compacts sessions over 200K tokens after about 54 idle minutes. How the cache math works, the setting to turn it off, and when to keep it.
- Claude Code Desktop SneakPeek Flaw: Fixed Version and What To DoSneakPeek (CVSS 8.7) let a poisoned HTML file read SSH keys and cloud credentials via the Claude Code Desktop preview pane. Fixed in Claude Desktop 1.30096.1.
- Anthropic Self-Replicating AI Research: What Small Models Can Actually DoAnthropic's Frontier Red Team says small open models may be months from self-replicating across cheap IoT devices. What it measured and where the claim is thin.
- Reverse Engineer Anything (REA): What the MCP Server Does and Where the Line IsREA (Reverse Engineer Anything) is an MIT-licensed MCP server that lets Claude Code, Codex or Cursor inspect binaries, Electron apps and APKs. How to try it.
- Anthropic Scion: Why Anthropic Replaced Git for Agent-Scale MergesAnthropic Scion replaced git after merges grew to over 30,000 a day. What Anthropic's post says, what HN pushed back on and what to apply to your own repo.
- Claude Code Projects: Coordinator, Threads, and LimitsClaude Code Projects is open to waitlisted Pro and Max users. How the coordinator and cloud threads work, what they cost in plan limits and where it breaks.
FAQ
How much does Claude Fable 5.1 cost per million tokens?
Claude Fable 5.1 costs $10 per 1M input tokens and $50 per 1M output tokens on Anthropic's first-party API, per platform.claude.com on October 9, 2026. Per 1M tokens, cache reads cost $0.25, and the batch rate is $5 input and $25 output.
What is Claude Fable 5.1's context window?
Claude Fable 5.1 has a 1,000,000-token context window and returns up to 128,000 output tokens per response.
Are Claude Fable 5.1's weights open?
No. Claude Fable 5.1 is a closed-weights model. You call it through Anthropic's API as claude-fable-5-1 or through Vercel AI Gateway as anthropic/claude-fable-5.1.
When was Claude Fable 5.1 released?
Anthropic released Claude Fable 5.1 on September 1, 2026.
Sources
Last verified from platform.claude.com.
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